The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around...The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around the rotation axis of the spinning Earth during the growth of the core the rotation should have been accelerated. Controversially the tidal dissipation by the Moon, which is mainly dependent on the availability of open shallow seas and the kind of Moon escape from a nearby position, acts towards a deceleration of the rotating Earth. Measurements of LOD for Phanerozoic and Precambrian times open ways to solve questions concerning the geodynamical history of the Earth. These measurements encompass investigations of growth patterns in fossils and depositional patterns in sediments (Cyclostratigraphy, Tidalites, Stromatolites, Rhythmites). These patterns contain information on the LOD and on the changing distance between Earth and Moon and can be used as well for a discussion about the growth of the Earth’s core. By updating an older paper with its simple approach as well as incorporating newly published results provided by the geoscientific community, a moderate to fast growth of the core in a hot early Earth will be favored controversially to the assumption of a delayed development of the core in an originally cold Earth. Core development with acceleration of Earth’s rotation and the contemporaneous slowing down due to tidal dissipation during the filling of the ocean may significantly interrelate.展开更多
Scientists pay great attention to different-time-scale signals in the lengllh of day (LOD) variations △LOD, which provide signatures of the Earth's interior structure, couplings among different layers, and potenti...Scientists pay great attention to different-time-scale signals in the lengllh of day (LOD) variations △LOD, which provide signatures of the Earth's interior structure, couplings among different layers, and potential excitations of ocean and atmosphere. In this study, based on the ensemble empirical mode decomposition (EEMD), we analyzed the latest time series of △LOD data spanning from January 1962 to March 2015. We observed the signals with periods and amplitudes of about 0.5 month and 0.19 ms, 1.0 month and 0.19 ms, 0.5 yr and 0.22 ms, 1.0 yr and 0.18 ms, 2.28 yr and 0.03 ms, 5.48 yr and 0.05 ms, respectively, in coincidence with the results of predecessors. In addition, some signals that were previously not definitely observed by predecessors were detected in this study, with periods and amplitudes of 9.13 d and 0.12 ms, 13.69 yr and 0.10 ms, respectively. The mechanisms of the LOD fluctuations of these two signals are still open.展开更多
The plant-pollinator‘arms race’model posits that a major driver of the evolution of elongated corollas in flowers is reciprocal selection for‘morphological fit’between pollinator-tongue length and access distance ...The plant-pollinator‘arms race’model posits that a major driver of the evolution of elongated corollas in flowers is reciprocal selection for‘morphological fit’between pollinator-tongue length and access distance to nectar(usually corolla-tube length).Evidence for the pollinator-mediated selection on tube length and evolution of multiple,correlated floral traits remains inconclusive.To gain possible insights into the strength of stabilizing selection by assessing standing phenotypic variation,we measured a series of functionally important floral traits,including corolla tube length and‘effective’tube depth and degree of style coiling.We then calculated coefficients of variation(CV)for these traits in three field populations of R.schneideriana.Unlike in most long-tubed flowers,the bottom part of the corolla tube is completely occupied by the style,with no room for nectar.The length of this portion of the corolla tube was more variable(higher CV)than the upper part of the corolla tube,suggesting that functional tube depth was under stronger stabilizing selection.The degree of style coiling was negatively related to the corolla-tube length in all three populations of R.schneideriana,suggesting that there may be conflicting selection acting on style length and corolla-tube length,which are otherwise usually tightly correlated.Given the lack of nectar in the flowers of this species,the long corolla tubes and long styles may represent morphological holdovers from ancestors that were pollinated by long-tongued pollinators,as is still seen in related species in the western Himalayas.展开更多
The frequent occurrence of dry and hot(DH)days in South China in summer has a negative impact on social development and human health.This study explored the variation characteristics of DH days and the possible reason...The frequent occurrence of dry and hot(DH)days in South China in summer has a negative impact on social development and human health.This study explored the variation characteristics of DH days and the possible reasons for this knotty problem.The findings revealed a notable increase in the number of DH days across most stations,indicating a significant upward trend.Additionally,DH events were observed to occur frequently.The number of DH days increased during 1970-1990,decreased from 1991 to 1997,and stayed stable after 1997.The key climate factors affecting the interannual variability of the number of DH days were the Indian Ocean Basin warming(IOBW)in spring and the East Asian Summer Monsoon(EASM).Compared with the negative phase of IOBW,in the positive phase of IOBW,500 hPa and 850 hPa geopotential height enhanced,the West Pacific subtropical high strengthened and extended abnormally to the west,more solar radiation reached the surface,surface outgoing longwave radiation increased,and there was an anomalous anticyclone in eastern South China.The atmospheric circulation characteristics of the positive and negative phases of ESAM were opposite to those of IOBW,and the abnormal circulation of the positive(negative)phases of ESAM was unfavorable(favorable)for the increase in the number of DH days.A long-term prediction model for the number of summer DH days was established using multiple linear regression,incorporating the key climate factors.The correlation coefficient between the observed and predicted number of DH days was 0.65,and the root-mean-square error was 2.8.In addition,independent forecasts for 2019 showed a deviation of just 1 day.The results of the independent recovery test confirmed the stability of the model,providing evidence that climatic factors did have an impact on DH days in South China.展开更多
[ Objective] The research aimed to analyze temporal-spatial variation characteristics of the extreme precipitation days over South China from 1961 to 2010. [ Method] Based on the daily precipitation data in meteorolog...[ Objective] The research aimed to analyze temporal-spatial variation characteristics of the extreme precipitation days over South China from 1961 to 2010. [ Method] Based on the daily precipitation data in meteorological stations over South China, extreme precipitation thresholds were determined according to the percentiles distribution for different stations. Temporal-spatial variation characteristics of the extreme precipitation days over South China were studied by the methods of fuzzy clustering, trend coefficient, wavelet analysis and cross spectrum analysis, etc. [ Re- suit] Four sub-regions were identified over South China. They were respectively Nanling area, west Guangxi area, Coast area and Hainan area. Occurrence seasons of the extreme precipitations in each sub-region were significantly different. Extreme precipitation clays in four sub-regions all had increase trends, and those of Nanling area and Coast area were significant. From wavelet analysis and cress spectrum analysis, there were significant periodic variation characteristics. Extreme precipitation days in each sub-region all had significant same-phase evolution trends at the peri- od of 2 -5 years, but backward time length was different. [ Conclusion] The research provided background materials for forecast and influence as- sessment of the extremely heavy precipitation over South China.展开更多
The effect of day length and temperature on the pollen fertility of five photoperiod-sensitive genic male-sterile japonica rice lines (PGMSR) and three temperature-sensitive genic malesterile indica rice lines (TGMSR)...The effect of day length and temperature on the pollen fertility of five photoperiod-sensitive genic male-sterile japonica rice lines (PGMSR) and three temperature-sensitive genic malesterile indica rice lines (TGMSR) were investigated in phytotron. The light source used for illumination was xenon lamp, and the light intensity which plant accepted on the leaf surface was 300—350μmol photons ms. The results indicated that pollens of PGMSR 7001S and E47S aborted completely whereas a little part of 31116S pollens appeared normal under long day photoperiod (LD,25℃,15h) (Table 1). High temperature (HT, 30℃, 12h) and lower temperature (LT,展开更多
Air temperature and photoperiod play an important role in the seedling development for tropical forest species.Both variables are sensitive to climate,and so evaluating thermal and photoperiodic effects on seedling de...Air temperature and photoperiod play an important role in the seedling development for tropical forest species.Both variables are sensitive to climate,and so evaluating thermal and photoperiodic effects on seedling development is fundamental,especially for climate change studies.Methods to quantify thermal time and the energy required for plants to reach a development stage include air temperature and cardinal temperatures.The photoperiod will also affect physiological reactions of a plant and thus its development.Here we evaluated the six thermal time methods widely used to compute thermal requirement,and identified the influence of the photoperiod from the 2015 and2016 growing seasons and 12 sowing dates in Itajubá,Minas Gerais state,Brazil,on seedling development of three native tropical forest species Psidium guajava L.(Myrtaceae),Citharexylum myrianthum Cham.(Verbenaceae),and Bixa orellana L.(Bixaceae).The method used to quantify thermal time influenced the analytical results of seedling development;the one that considered three cardinal temperatures and compared them with the mean air temperature(Method5)performed better in computing thermal requirements.The influence of photoperiod on seedling development was inconclusive for the three species,but all three developed better in mild temperatures(between 13.3℃and 26.9℃)with a photoperiod shorter than 13 h.展开更多
By using the observational snow data of more than 700 weather stations,the interannual temporal and spatial characteristics of seasonal snow cover in China were analyzed.The results show that northern Xinjiang,northea...By using the observational snow data of more than 700 weather stations,the interannual temporal and spatial characteristics of seasonal snow cover in China were analyzed.The results show that northern Xinjiang,northeastern China–Inner Mongolia,and the southwestern and southern portions of Tibetan Plateau are three regions in China with high seasonal snow cover and also an interannual anomaly of snow cover.According to the trend of both the snow depth and snow cover days,there are three changing patterns for the seasonal snow cover:The first type is that both snow depth and snow cover days simultaneously increase or decrease;this includes northern Xinjiang,middle and eastern Inner Mongolia,and so on.The second is that snow depth increases but snow cover days decrease;this type mainly locates in the eastern parts of the northeastern plain of China and the upper reaches of the Yangtze River.The last type is that snow depth decreases but snow cover days increase at the same time such as that in middle parts of Tibetan Plateau.Snow cover in China appears to have been having a slow increasing trend during the last 40 years.On the decadal scale,snow depth and snow cover days slightly increased in the 1960s and then decreased in the 1970s;they again turn to increasing in the 1980s and persist into 1990s.展开更多
Using the data of 545 meteorological stations in 1961-2015,according to the rainfall intensity classification standard issued by the China Meteorological Administration,the rainfall events were divided into six intens...Using the data of 545 meteorological stations in 1961-2015,according to the rainfall intensity classification standard issued by the China Meteorological Administration,the rainfall events were divided into six intensities: light rain,moderate rain,heavy rain,torrential rain,downpour and heavy downpour. The latter three were recorded as total torrential rain,and all the six were recorded as the total rainfall. In terms of the interannual rainfall and rainy days,the whole China was regarded as an object. Firstly,the annual rainfall and rainy day of different intensity of rainfalls of 545 stations in 1961-2015 were calculated. Then,the variation trend of rainfall and rainy days was calculated. Finally,the variation trend of contribution of different intensity of rainfalls and rainy days to total rainfall and rainy days were diagnosed. It obtained the following results.( i) The light rain in China was declining from 1961 to 2015,and the trend values of light rain and rainy days were-411. 44 mm/yr and-136. 99 d/yr,respectively. Heavy rain and total heavy rainfall showed an increasing trend,with rainfall and rainy day trends of 127. 02 and 463. 94 mm/yr and 7. 93 and 4. 24 d/yr,respectively. The total rainfall showed a ' hockey' phenomenon of ' first rise,then decline',and the trend values of rainfall and rainy days were 204. 29 mm/yr and-95. 81 d/yr,respectively. Except the northern region,the rainfall in most parts of China was dominated by increasing trends and was moving towards extremes.( ii) In terms of rainfall contribution rate,the contribution of light rain to total rainfall showed a declining trend,and the trend values of rainfall and rainy day contribution were both-0. 11%/yr. The contribution of other intensity rainfalls to total rainfall showed an increasing trend. The contribution of torrential rain to the total torrential rain showed a declining trend. The contribution trends of rainfall and rainy days were-0. 06% and-0. 03%/yr,respectively. The contribution of downpour and heavy downpour to total torrential rain showed an increasing trend,indicating the intensity of torrential rain in China is increasing. Although the contribution rate of different intensity of rainfalls to total rainfall was different in different areas of China,the contribution rate of heavy rainfall to total rainfall in most areas showed an increasing trend.( iii) Through comparing the rainfall and rainy days of six different intensity of rainfalls,it can be found that China’s heavy rainfall events are increasing and the rainfall intensity is developing towards extremes.展开更多
Based on data of hail days at 2 481 stations during 1961-2016,the temporal and spatial distribution characteristics and periodic variation of gale days in China and seven geographical regions were analyzed by using a ...Based on data of hail days at 2 481 stations during 1961-2016,the temporal and spatial distribution characteristics and periodic variation of gale days in China and seven geographical regions were analyzed by using a variety of statistical methods. The results showed that: in time,the gale days in China and the seven geographical areas all showed a decreasing trend from 1961 to 2016. In the Tibet( Southeast China and Southwest China) region,the annual number of single-station gale days was the most( least),but the decrease ratio was the least( most). In the significance oscillation period,it was 14 years in the whole country,60 years in Northeastern China,Northern China and east part of Northwestern China,7,14 and 60 years in the west of Northwestern China,Southwestern China and Southeastern China,7 and 60 years in the Tibet region. The mutation of gale days generally occurred in 1991,1993,1989,1997,1986,1997,1992 and 1984 in the whole country,Northeastern China,Northern China,east part of Northwestern China,west part of Northwestern China,Tibet,Southwestern China and Southeastern China,but only the east of Northwestern China and Tibet region passed 0. 05 of significance test. In space,the annual average gale days showed the pattern of southeast low and northwest high in China from 1961 to 2016. The annual average gale days were more abundant in the central and western Tibet,the southern Qinghai,eastern Xinjiang,western Sichuan,northern Inner Mongolia and northern Gansu. These regions were dominated by positive anomaly in the 1970 s and the 1980 s,but negative in other decades. Annual gale days in most regions of China showed a decreasing trend during 1961-2016,and fluctuation presented high in east region and low in west region beside " Hu Huanyong line".展开更多
[Objective] The aim was to study the variation characteristics of longest continuous rainfall days in Shenyang in recent 48 years. [Method] Based on the data of longest continuous rainfall days in Shenyang from May to...[Objective] The aim was to study the variation characteristics of longest continuous rainfall days in Shenyang in recent 48 years. [Method] Based on the data of longest continuous rainfall days in Shenyang from May to September in 1961-2008, the variation characteristics of longest continuous rainfall days in Shenyang in recent 48 years was analyzed by means of one-dimensional linear trend estimation and wavelet analysis method. [Result] In recent 48 years, the longest continuous rainfall days in Shenyang showed decrease trend from May to September except for June in which it showed increased; the total longest continuous rainfall days showed decrease trend, and the maximum value appeared in 1986, while the minimum value could be found in 1997; from periodic variation, the total longest continuous rainfall days had the period of 2-3 years, and there also existed the period of 5-7 years after 1980; the total longest continuous rainfall days were more from the beginning of 1960s to the middle of 1990s and less thereafter. [Conclusion] The study could provide theoretical foundation for the deep research on climate change in Shenyang.展开更多
The tropical storm day(TSD)is a combined measure of genesis and lifespan.It reflects tropical cyclone(TC)overall activity,yet its variability has rarely been studied,especially globally.Here we show that the global to...The tropical storm day(TSD)is a combined measure of genesis and lifespan.It reflects tropical cyclone(TC)overall activity,yet its variability has rarely been studied,especially globally.Here we show that the global total TSDs exhibit pronounced interannual(3-6 years)and decadal(10 years)variations over the past five-to-six decades without a significant trend.The leading modes of the interannual and decadal variability of global TSD feature similar patterns in the western Pacific and Atlantic,but different patterns in the Eastern Pacific and the Southern Indian Ocean.The interannual and decadal leading modes are primarily linked to El Ni?o-Southern Oscillation(ENSO)and Pacific Decadal Oscillation(PDO),respectively.The TSDs-ENSO relationship has been steady during the entire 55-year period,but the TSDs-PDO relationship has experienced a breakdown in the 1980 s.We find that the decadal variation of TSD in the Pacific is associated with the PDO sea surface temperature(SST)anomalies in the tropical eastern Pacific(PDO-E),while that in the Atlantic and the Indian Ocean is associated with the PDO SST anomalies in the western Pacific(PDO-W).However,the PDO-E and PDO-W SST anomalies are poorly coupled in the 1980 s,and this"destructive PDO"pattern results in a breakdown of the TSDs-PDO relationship.The results here have an important implication for seasonal to decadal predictions of global TSD.展开更多
The present paper deals with within ramet radial, intra- and inter-clonal variations in the wood element’s dimensions and specific gravity of 10 clones of Populus deltoides Bartr. ex Marsh. The growth parameters name...The present paper deals with within ramet radial, intra- and inter-clonal variations in the wood element’s dimensions and specific gravity of 10 clones of Populus deltoides Bartr. ex Marsh. The growth parameters namely ramet height and DBH were also considered for the study. Study material was collected from the 10 clones of Populus deltoids raised by WIMCO Plantations Ltd. at Rudrapur (Udhamsingh Nagar), India. Three clones were parent viz. G48, S7C8 (female) and G3 (male). Other clones represent hybrids of F1 generation. Inter- and intra-clonal variations were significant for all the wood traits except vessel element length for intra-clonal variations. Within ramet variations due to radial location were significant for fiber length and specific gravity with increasing trend from pith to periphery. Interaction of clone*replication was also significant for all the wood traits. Variations were significant for the DBH for the clones. Fiber length and specific gravity was significantly higher in female while wall thickness and vessel element length was in male clones (P < 0.01). Female parents (G48 and S7C8) showed higher fiber length and specific gravity than of the male parent (G3) while vessel element diameter and wall thickness was higher in male parent (G3). Fiber length was higher in offspring than the parent clones which may be the reflection of hybrid vigor for the trait. The clones of F1 offspring followed the similar patterns for the other wood traits as in the parent clones. Hierarchical cluster analysis showed that W/A 39 (male) and W 39 (female) clones of F1 generation were highly divergent than of the other clones.展开更多
The performance and variability patterns in the wood element’s dimensions, specific gravity and growth parameters namely ramet height and GBH were evaluated in 16 clones of parents, F1 and F2 hybrids of Populus delto...The performance and variability patterns in the wood element’s dimensions, specific gravity and growth parameters namely ramet height and GBH were evaluated in 16 clones of parents, F1 and F2 hybrids of Populus deltoides Bartr. ex Marsh. Ramet radial variations were nonsignificant, while inter-clonal variations due to interaction of clone/replication were significant for all the wood traits except vessel element length. Inter-clonal variations were significant only for fiber length and fiber wall thickness. Fiber length and specific gravity were significantly higher in female, while wall thickness and vessel element length were higher in male clones. Female parents (G48 and S7C8) showed higher fiber length and specific gravity than of the male parent (G3), while vessel diameter and wall thickness were higher in male par- ent (G3). There is not much difference in fiber length and vessel element’s dimensions among the parents, F1 and F2 generation hybrid clones. Specific gravity did not showed any trend for parents, F1 and F2 generations. Generally female clones showed higher growth rate. Broad sense heritability for wood traits ranged from 0.143 (fiber length) to 0.505 (fiber wall thickness), while for growth traits it was 0.374 (GBH) and 0.418 (height). Genetic gain for all the wood and growth traits was positive for most of the wood traits. The highly divergent male clone (78) and female clones (S7C8, G48, W/A 49) in number of combinations could be used for developing new hybrids of desired wood traits to develop new clones.展开更多
The size distribution of airborne dust particles is an important parameter in the measurement of dust emissions due to wind erosion,and a quantitative and accurate description is necessary.Observations regarding the s...The size distribution of airborne dust particles is an important parameter in the measurement of dust emissions due to wind erosion,and a quantitative and accurate description is necessary.Observations regarding the size distribution of airborne dust particles are currently lacking in Tibetan Plateau(TP).This study aims to obtain a dust particle size distribution and compare the difference in spatial distribution at a field site(FS)and two urban observation sites(Minfeng and Hetian),in the north of the TP,under the condition of the dust-days and clear-days.The observation data was collected from 5 July to 4 August,2019.The mass concentration of dust(PM20)was measured with a 10-stage quartz crystal microbalance cascade impactor.The results suggested that 91.9%of the particles were less than 1.4μm on clear-days,and particles of d≥1.4μm increased to 27.2%with the occurrence of the dust events.More than 80%of the airborne dust particles were less than 1.4μm for each friction velocity.The proportion of d<0.7μm was the greatest at 3.0 m(above the surface,similarly hereinafter)on dust-days,while the proportion of d>0.7μm was the greatest at 0.5 m on clear-days.During urban observation,with the occurrence of dust events,the concentration of a particle size greater than 2.5μm increased most significantly in Minfeng,while the concentration of a particle size less than 0.7μm increased most significantly in Hetian.Moreover,the proportion of particles with d<0.7μm had the smallest difference,while the proportion of particles with d>1.4μm had the most obvious difference among these three sites.展开更多
Using foggy days and mean temperature and relative humidity data of 602 stations from January to December in the period 1961-2003 in China, the relationship between variations of foggy days and temperature and its pos...Using foggy days and mean temperature and relative humidity data of 602 stations from January to December in the period 1961-2003 in China, the relationship between variations of foggy days and temperature and its possible reason for the 43 years were analyzed by regression, correlation and contrastive analysis methods. The results show that the higher (lower) the mean temperature and the lower (higher) the relative humidity correspond to less (more) foggy days, the relationship is the best in the western, northern and eastern Sichuan, Yunnan-Guizhon Plateau, and southeast highland in China. This induces a decrease in relative humidity when the climate becomes warmer, and eventually brings about a decrease in foggy days in China.展开更多
Earth's variable rotation is mainly produced by the variability of the AAM(atmospheric angular momentum). In particular, the axial AAM component X_3, which undergoes especially strong variations,induces changes in ...Earth's variable rotation is mainly produced by the variability of the AAM(atmospheric angular momentum). In particular, the axial AAM component X_3, which undergoes especially strong variations,induces changes in the Earth's rotation rate. In this study we analysed maps of regional input into the effective axial AAM from 1948 through 2011 from NCEP/NCAR reanalysis. Global zonal circulation patterns related to the LOD(length of day) were described. We applied MSSA(Multichannel Singular Spectrum Analysis) jointly to the mass and motion components of AAM, which allowed us to extract annual, semiannual, 4-mo nth, quasi-biennial, 5-year, and low-frequency oscillations. PCs(Principal components) strongly related to ENSO(El Nino southern oscillation) were released. They can be used to study ENSO-induced changes in pressure and wind fields and their coupling to LOD. The PCs describing the trends have captured slow atmospheric circulation changes possibly related to climate variability.展开更多
We studied radial and inter-progeny variations in the dimen- sions of the wood elements and specific gravity of 21 half sib progenies of Populus deltoides Bartr. ex Marsh. The female parents of half sib progenies were...We studied radial and inter-progeny variations in the dimen- sions of the wood elements and specific gravity of 21 half sib progenies of Populus deltoides Bartr. ex Marsh. The female parents of half sib progenies were G48 and $7C13 clones. Variance ratio (F) test indicated that inter-progeny variations in the dimensions of wood elements and specific gravity were significant for all wood traits while variations were significant for radial location for specific gravity only. Hierarchical clus- ter analysis was done by Squared Euclidean Distance for all of 21 proge- nies considering six wood traits. 21 progenies were grouped into 4 clus- ters. Cluster 1 was the largest cluster with 11 progenies, whereas cluster 3 had only one progeny. Selected progenies in clusters 3 (progeny 155, male) and 4 (progeny 108, 196, both female) were highly divergent from the other progenies so they were used in combinations as parents of hybrids to develop new clones with desired characters. Progeny 155 showed higher growth, fiber dimensions, and specific gravity, thus, should be used for the development of new clones.展开更多
The induction of biofilm formation has been explored as a means of harvesting microalgae for bioprocessing applications. Environmental stressors have been implicated in the induction of biofilm formation;however, it i...The induction of biofilm formation has been explored as a means of harvesting microalgae for bioprocessing applications. Environmental stressors have been implicated in the induction of biofilm formation;however, it is unclear whether all stressors, or a select few, are responsible. This study aimed to investigate the effects of three stressors, nitrogen depletion, reduced or elongated day lengths, and increased culture turbulence on bio-film formation of Parachlorella kessleri. We also examined corresponding effects on growth and production of reactive oxygen species. Turbulence induced the greatest response in which a significant decrease in growth plus an increase in superoxide production and flocculation efficiency were seen for the 300-rpm treatment. For varying day lengths, stress response was not observed, however, a significant increase in EPS secretion was measured in both shorter and longer days. Nitrogen depletion induced a low-level stress response, in which superoxide production increased for the highest concentrations, while growth was not impacted. In contrast to previous studies on nitrogen depletion, a significant increase in EPS secretion was not observed. Results indicate that stress response varies according to type and magnitude. EPS production and thus biofilm formation are not linked to the stress indicators investigated. P. kessleri uses small quantities of EPS to contribute to cell stickiness, but not necessarily to the full formation of a biofilm;however, cell stickiness served as a mechanism for substrate adherence and cellular aggregation none the less.展开更多
The objective of the present study was to determine the optimum sowing time of three quinoa ecotypes (Altipllano, sea level, and valley) for high seed yields in south Kanto, Japan. Pot experiments were conducted in th...The objective of the present study was to determine the optimum sowing time of three quinoa ecotypes (Altipllano, sea level, and valley) for high seed yields in south Kanto, Japan. Pot experiments were conducted in the experimental field at Nihon University during 2011, 2012, 2013, and 2014. In this experiment, the following quinoa varieties were used NL-6, Baer Cajon and Cauquenes (sea-level type), Amarilla de Marangani, Blanca de Junin, CICA-127, ECU-420, ECU-525, Ingapirica, and Narino (valley type), 94R and Isluga (Altiplano type). The quinoa seeds were sown on March 29, June 17 and September 22, 2011;March 27, June 17 and August 28, 2012;March 26, June 15 and 5 September 5, 2013;and March 27, June 17 and August 28, 2014. When the sea-level type and Altiplano type seeds were sowed from March to September, the seeds could be gained in all sowing plots. However, the seed weights of all varieties were the highest in the sowing plots of March. And the seed weights in the sowing plot of March were significantly higher than that in the other sowing plots. The sea-level type and Altiplano type quinoa had almost the same seed growth reaction for day length and day temperature. Thus, to gain a high seed yield of the sea-level and Altiplano type quinoa, March was the optimum sowing time in south Kanto, Japan. When the valley-type seeds were sowed from March to June, the seeds could not be gained, except in 2012. In 2012, the seed weights and seed numbers in sowing plots of March and June were significantly lower than those in the sowing plot of September. Thus, to obtain a high seed yield of the valley type quinoa, the optimum sowing time in south Kanto, Japan was from August to September.展开更多
文摘The rotation of the Earth and the related length of the day (LOD) are predominantly affected by tidal dissipation through the Moon and the growth of the Earth’s core. Due to the increased concentration of mass around the rotation axis of the spinning Earth during the growth of the core the rotation should have been accelerated. Controversially the tidal dissipation by the Moon, which is mainly dependent on the availability of open shallow seas and the kind of Moon escape from a nearby position, acts towards a deceleration of the rotating Earth. Measurements of LOD for Phanerozoic and Precambrian times open ways to solve questions concerning the geodynamical history of the Earth. These measurements encompass investigations of growth patterns in fossils and depositional patterns in sediments (Cyclostratigraphy, Tidalites, Stromatolites, Rhythmites). These patterns contain information on the LOD and on the changing distance between Earth and Moon and can be used as well for a discussion about the growth of the Earth’s core. By updating an older paper with its simple approach as well as incorporating newly published results provided by the geoscientific community, a moderate to fast growth of the core in a hot early Earth will be favored controversially to the assumption of a delayed development of the core in an originally cold Earth. Core development with acceleration of Earth’s rotation and the contemporaneous slowing down due to tidal dissipation during the filling of the ocean may significantly interrelate.
基金supported by National 973 Project China (2013CB733305)National Natural Science Foundation of China (NSFCs) (41174011,41429401,41210006,41128003,41021061)
文摘Scientists pay great attention to different-time-scale signals in the lengllh of day (LOD) variations △LOD, which provide signatures of the Earth's interior structure, couplings among different layers, and potential excitations of ocean and atmosphere. In this study, based on the ensemble empirical mode decomposition (EEMD), we analyzed the latest time series of △LOD data spanning from January 1962 to March 2015. We observed the signals with periods and amplitudes of about 0.5 month and 0.19 ms, 1.0 month and 0.19 ms, 0.5 yr and 0.22 ms, 1.0 yr and 0.18 ms, 2.28 yr and 0.03 ms, 5.48 yr and 0.05 ms, respectively, in coincidence with the results of predecessors. In addition, some signals that were previously not definitely observed by predecessors were detected in this study, with periods and amplitudes of 9.13 d and 0.12 ms, 13.69 yr and 0.10 ms, respectively. The mechanisms of the LOD fluctuations of these two signals are still open.
基金This work was supported by the National Natural Science Foundation of China(grant nos.31270281,32030071)to SQHNNSFC(32071671)to ZYT.
文摘The plant-pollinator‘arms race’model posits that a major driver of the evolution of elongated corollas in flowers is reciprocal selection for‘morphological fit’between pollinator-tongue length and access distance to nectar(usually corolla-tube length).Evidence for the pollinator-mediated selection on tube length and evolution of multiple,correlated floral traits remains inconclusive.To gain possible insights into the strength of stabilizing selection by assessing standing phenotypic variation,we measured a series of functionally important floral traits,including corolla tube length and‘effective’tube depth and degree of style coiling.We then calculated coefficients of variation(CV)for these traits in three field populations of R.schneideriana.Unlike in most long-tubed flowers,the bottom part of the corolla tube is completely occupied by the style,with no room for nectar.The length of this portion of the corolla tube was more variable(higher CV)than the upper part of the corolla tube,suggesting that functional tube depth was under stronger stabilizing selection.The degree of style coiling was negatively related to the corolla-tube length in all three populations of R.schneideriana,suggesting that there may be conflicting selection acting on style length and corolla-tube length,which are otherwise usually tightly correlated.Given the lack of nectar in the flowers of this species,the long corolla tubes and long styles may represent morphological holdovers from ancestors that were pollinated by long-tongued pollinators,as is still seen in related species in the western Himalayas.
基金National Natural Science Foundation of China(92044302,41805115)Guangzhou Municipal Science and Technology Project(202002020065)。
文摘The frequent occurrence of dry and hot(DH)days in South China in summer has a negative impact on social development and human health.This study explored the variation characteristics of DH days and the possible reasons for this knotty problem.The findings revealed a notable increase in the number of DH days across most stations,indicating a significant upward trend.Additionally,DH events were observed to occur frequently.The number of DH days increased during 1970-1990,decreased from 1991 to 1997,and stayed stable after 1997.The key climate factors affecting the interannual variability of the number of DH days were the Indian Ocean Basin warming(IOBW)in spring and the East Asian Summer Monsoon(EASM).Compared with the negative phase of IOBW,in the positive phase of IOBW,500 hPa and 850 hPa geopotential height enhanced,the West Pacific subtropical high strengthened and extended abnormally to the west,more solar radiation reached the surface,surface outgoing longwave radiation increased,and there was an anomalous anticyclone in eastern South China.The atmospheric circulation characteristics of the positive and negative phases of ESAM were opposite to those of IOBW,and the abnormal circulation of the positive(negative)phases of ESAM was unfavorable(favorable)for the increase in the number of DH days.A long-term prediction model for the number of summer DH days was established using multiple linear regression,incorporating the key climate factors.The correlation coefficient between the observed and predicted number of DH days was 0.65,and the root-mean-square error was 2.8.In addition,independent forecasts for 2019 showed a deviation of just 1 day.The results of the independent recovery test confirmed the stability of the model,providing evidence that climatic factors did have an impact on DH days in South China.
文摘[ Objective] The research aimed to analyze temporal-spatial variation characteristics of the extreme precipitation days over South China from 1961 to 2010. [ Method] Based on the daily precipitation data in meteorological stations over South China, extreme precipitation thresholds were determined according to the percentiles distribution for different stations. Temporal-spatial variation characteristics of the extreme precipitation days over South China were studied by the methods of fuzzy clustering, trend coefficient, wavelet analysis and cross spectrum analysis, etc. [ Re- suit] Four sub-regions were identified over South China. They were respectively Nanling area, west Guangxi area, Coast area and Hainan area. Occurrence seasons of the extreme precipitations in each sub-region were significantly different. Extreme precipitation clays in four sub-regions all had increase trends, and those of Nanling area and Coast area were significant. From wavelet analysis and cress spectrum analysis, there were significant periodic variation characteristics. Extreme precipitation days in each sub-region all had significant same-phase evolution trends at the peri- od of 2 -5 years, but backward time length was different. [ Conclusion] The research provided background materials for forecast and influence as- sessment of the extremely heavy precipitation over South China.
文摘The effect of day length and temperature on the pollen fertility of five photoperiod-sensitive genic male-sterile japonica rice lines (PGMSR) and three temperature-sensitive genic malesterile indica rice lines (TGMSR) were investigated in phytotron. The light source used for illumination was xenon lamp, and the light intensity which plant accepted on the leaf surface was 300—350μmol photons ms. The results indicated that pollens of PGMSR 7001S and E47S aborted completely whereas a little part of 31116S pollens appeared normal under long day photoperiod (LD,25℃,15h) (Table 1). High temperature (HT, 30℃, 12h) and lower temperature (LT,
基金the Minas Gerais Research Support Foundation(FAPEMIG,APQ-01392-13 and APQ 01258-17)the Coordination for the Improvement of Higher Education Personnel(Capes,process numbers 88887.613734/2021-00,and 1827878)+1 种基金the FAPEMIG(process number ID 14029)National Council for Scientific and Technological Development(CNPq,process number306845/2021-0)。
文摘Air temperature and photoperiod play an important role in the seedling development for tropical forest species.Both variables are sensitive to climate,and so evaluating thermal and photoperiodic effects on seedling development is fundamental,especially for climate change studies.Methods to quantify thermal time and the energy required for plants to reach a development stage include air temperature and cardinal temperatures.The photoperiod will also affect physiological reactions of a plant and thus its development.Here we evaluated the six thermal time methods widely used to compute thermal requirement,and identified the influence of the photoperiod from the 2015 and2016 growing seasons and 12 sowing dates in Itajubá,Minas Gerais state,Brazil,on seedling development of three native tropical forest species Psidium guajava L.(Myrtaceae),Citharexylum myrianthum Cham.(Verbenaceae),and Bixa orellana L.(Bixaceae).The method used to quantify thermal time influenced the analytical results of seedling development;the one that considered three cardinal temperatures and compared them with the mean air temperature(Method5)performed better in computing thermal requirements.The influence of photoperiod on seedling development was inconclusive for the three species,but all three developed better in mild temperatures(between 13.3℃and 26.9℃)with a photoperiod shorter than 13 h.
文摘By using the observational snow data of more than 700 weather stations,the interannual temporal and spatial characteristics of seasonal snow cover in China were analyzed.The results show that northern Xinjiang,northeastern China–Inner Mongolia,and the southwestern and southern portions of Tibetan Plateau are three regions in China with high seasonal snow cover and also an interannual anomaly of snow cover.According to the trend of both the snow depth and snow cover days,there are three changing patterns for the seasonal snow cover:The first type is that both snow depth and snow cover days simultaneously increase or decrease;this includes northern Xinjiang,middle and eastern Inner Mongolia,and so on.The second is that snow depth increases but snow cover days decrease;this type mainly locates in the eastern parts of the northeastern plain of China and the upper reaches of the Yangtze River.The last type is that snow depth decreases but snow cover days increase at the same time such as that in middle parts of Tibetan Plateau.Snow cover in China appears to have been having a slow increasing trend during the last 40 years.On the decadal scale,snow depth and snow cover days slightly increased in the 1960s and then decreased in the 1970s;they again turn to increasing in the 1980s and persist into 1990s.
基金Supported by Project of National Natural Science Foundation of China(41801064)China Postdoctoral Science Foundation(2019T120114+1 种基金 2019M650756)Central Asian Atmospheric Science Research Fund(CAAS201804)
文摘Using the data of 545 meteorological stations in 1961-2015,according to the rainfall intensity classification standard issued by the China Meteorological Administration,the rainfall events were divided into six intensities: light rain,moderate rain,heavy rain,torrential rain,downpour and heavy downpour. The latter three were recorded as total torrential rain,and all the six were recorded as the total rainfall. In terms of the interannual rainfall and rainy days,the whole China was regarded as an object. Firstly,the annual rainfall and rainy day of different intensity of rainfalls of 545 stations in 1961-2015 were calculated. Then,the variation trend of rainfall and rainy days was calculated. Finally,the variation trend of contribution of different intensity of rainfalls and rainy days to total rainfall and rainy days were diagnosed. It obtained the following results.( i) The light rain in China was declining from 1961 to 2015,and the trend values of light rain and rainy days were-411. 44 mm/yr and-136. 99 d/yr,respectively. Heavy rain and total heavy rainfall showed an increasing trend,with rainfall and rainy day trends of 127. 02 and 463. 94 mm/yr and 7. 93 and 4. 24 d/yr,respectively. The total rainfall showed a ' hockey' phenomenon of ' first rise,then decline',and the trend values of rainfall and rainy days were 204. 29 mm/yr and-95. 81 d/yr,respectively. Except the northern region,the rainfall in most parts of China was dominated by increasing trends and was moving towards extremes.( ii) In terms of rainfall contribution rate,the contribution of light rain to total rainfall showed a declining trend,and the trend values of rainfall and rainy day contribution were both-0. 11%/yr. The contribution of other intensity rainfalls to total rainfall showed an increasing trend. The contribution of torrential rain to the total torrential rain showed a declining trend. The contribution trends of rainfall and rainy days were-0. 06% and-0. 03%/yr,respectively. The contribution of downpour and heavy downpour to total torrential rain showed an increasing trend,indicating the intensity of torrential rain in China is increasing. Although the contribution rate of different intensity of rainfalls to total rainfall was different in different areas of China,the contribution rate of heavy rainfall to total rainfall in most areas showed an increasing trend.( iii) Through comparing the rainfall and rainy days of six different intensity of rainfalls,it can be found that China’s heavy rainfall events are increasing and the rainfall intensity is developing towards extremes.
基金Supported by the National Natural Science Foundation of China(41801064,71790611)the Climate Change Project of China Meteorological Administration(CCSF201843,CCSF201844)the Central Asia Atmospheric Science Research Fund(CAAS201804)
文摘Based on data of hail days at 2 481 stations during 1961-2016,the temporal and spatial distribution characteristics and periodic variation of gale days in China and seven geographical regions were analyzed by using a variety of statistical methods. The results showed that: in time,the gale days in China and the seven geographical areas all showed a decreasing trend from 1961 to 2016. In the Tibet( Southeast China and Southwest China) region,the annual number of single-station gale days was the most( least),but the decrease ratio was the least( most). In the significance oscillation period,it was 14 years in the whole country,60 years in Northeastern China,Northern China and east part of Northwestern China,7,14 and 60 years in the west of Northwestern China,Southwestern China and Southeastern China,7 and 60 years in the Tibet region. The mutation of gale days generally occurred in 1991,1993,1989,1997,1986,1997,1992 and 1984 in the whole country,Northeastern China,Northern China,east part of Northwestern China,west part of Northwestern China,Tibet,Southwestern China and Southeastern China,but only the east of Northwestern China and Tibet region passed 0. 05 of significance test. In space,the annual average gale days showed the pattern of southeast low and northwest high in China from 1961 to 2016. The annual average gale days were more abundant in the central and western Tibet,the southern Qinghai,eastern Xinjiang,western Sichuan,northern Inner Mongolia and northern Gansu. These regions were dominated by positive anomaly in the 1970 s and the 1980 s,but negative in other decades. Annual gale days in most regions of China showed a decreasing trend during 1961-2016,and fluctuation presented high in east region and low in west region beside " Hu Huanyong line".
文摘[Objective] The aim was to study the variation characteristics of longest continuous rainfall days in Shenyang in recent 48 years. [Method] Based on the data of longest continuous rainfall days in Shenyang from May to September in 1961-2008, the variation characteristics of longest continuous rainfall days in Shenyang in recent 48 years was analyzed by means of one-dimensional linear trend estimation and wavelet analysis method. [Result] In recent 48 years, the longest continuous rainfall days in Shenyang showed decrease trend from May to September except for June in which it showed increased; the total longest continuous rainfall days showed decrease trend, and the maximum value appeared in 1986, while the minimum value could be found in 1997; from periodic variation, the total longest continuous rainfall days had the period of 2-3 years, and there also existed the period of 5-7 years after 1980; the total longest continuous rainfall days were more from the beginning of 1960s to the middle of 1990s and less thereafter. [Conclusion] The study could provide theoretical foundation for the deep research on climate change in Shenyang.
基金supported by the National Science Foundation(Climate Dynamics Division)Award#NSF 2025057the National Natural Science Foundation of China(Grant No.91437218)the High-Performance Computing Center of Nanjing University of Information Science&Technology for their support of this work。
文摘The tropical storm day(TSD)is a combined measure of genesis and lifespan.It reflects tropical cyclone(TC)overall activity,yet its variability has rarely been studied,especially globally.Here we show that the global total TSDs exhibit pronounced interannual(3-6 years)and decadal(10 years)variations over the past five-to-six decades without a significant trend.The leading modes of the interannual and decadal variability of global TSD feature similar patterns in the western Pacific and Atlantic,but different patterns in the Eastern Pacific and the Southern Indian Ocean.The interannual and decadal leading modes are primarily linked to El Ni?o-Southern Oscillation(ENSO)and Pacific Decadal Oscillation(PDO),respectively.The TSDs-ENSO relationship has been steady during the entire 55-year period,but the TSDs-PDO relationship has experienced a breakdown in the 1980 s.We find that the decadal variation of TSD in the Pacific is associated with the PDO sea surface temperature(SST)anomalies in the tropical eastern Pacific(PDO-E),while that in the Atlantic and the Indian Ocean is associated with the PDO SST anomalies in the western Pacific(PDO-W).However,the PDO-E and PDO-W SST anomalies are poorly coupled in the 1980 s,and this"destructive PDO"pattern results in a breakdown of the TSDs-PDO relationship.The results here have an important implication for seasonal to decadal predictions of global TSD.
文摘The present paper deals with within ramet radial, intra- and inter-clonal variations in the wood element’s dimensions and specific gravity of 10 clones of Populus deltoides Bartr. ex Marsh. The growth parameters namely ramet height and DBH were also considered for the study. Study material was collected from the 10 clones of Populus deltoids raised by WIMCO Plantations Ltd. at Rudrapur (Udhamsingh Nagar), India. Three clones were parent viz. G48, S7C8 (female) and G3 (male). Other clones represent hybrids of F1 generation. Inter- and intra-clonal variations were significant for all the wood traits except vessel element length for intra-clonal variations. Within ramet variations due to radial location were significant for fiber length and specific gravity with increasing trend from pith to periphery. Interaction of clone*replication was also significant for all the wood traits. Variations were significant for the DBH for the clones. Fiber length and specific gravity was significantly higher in female while wall thickness and vessel element length was in male clones (P < 0.01). Female parents (G48 and S7C8) showed higher fiber length and specific gravity than of the male parent (G3) while vessel element diameter and wall thickness was higher in male parent (G3). Fiber length was higher in offspring than the parent clones which may be the reflection of hybrid vigor for the trait. The clones of F1 offspring followed the similar patterns for the other wood traits as in the parent clones. Hierarchical cluster analysis showed that W/A 39 (male) and W 39 (female) clones of F1 generation were highly divergent than of the other clones.
文摘The performance and variability patterns in the wood element’s dimensions, specific gravity and growth parameters namely ramet height and GBH were evaluated in 16 clones of parents, F1 and F2 hybrids of Populus deltoides Bartr. ex Marsh. Ramet radial variations were nonsignificant, while inter-clonal variations due to interaction of clone/replication were significant for all the wood traits except vessel element length. Inter-clonal variations were significant only for fiber length and fiber wall thickness. Fiber length and specific gravity were significantly higher in female, while wall thickness and vessel element length were higher in male clones. Female parents (G48 and S7C8) showed higher fiber length and specific gravity than of the male parent (G3), while vessel diameter and wall thickness were higher in male par- ent (G3). There is not much difference in fiber length and vessel element’s dimensions among the parents, F1 and F2 generation hybrid clones. Specific gravity did not showed any trend for parents, F1 and F2 generations. Generally female clones showed higher growth rate. Broad sense heritability for wood traits ranged from 0.143 (fiber length) to 0.505 (fiber wall thickness), while for growth traits it was 0.374 (GBH) and 0.418 (height). Genetic gain for all the wood and growth traits was positive for most of the wood traits. The highly divergent male clone (78) and female clones (S7C8, G48, W/A 49) in number of combinations could be used for developing new hybrids of desired wood traits to develop new clones.
基金funded by the National Natural Science Foundation of China(41875019&41905009)Basic Business Expenses(IDM2019002&IDM2016005)+1 种基金Chinese Desert Meteorological Science Research Found(Sqj2018019)Flexible Talents Introducing Project of Xinjiang(2018)。
文摘The size distribution of airborne dust particles is an important parameter in the measurement of dust emissions due to wind erosion,and a quantitative and accurate description is necessary.Observations regarding the size distribution of airborne dust particles are currently lacking in Tibetan Plateau(TP).This study aims to obtain a dust particle size distribution and compare the difference in spatial distribution at a field site(FS)and two urban observation sites(Minfeng and Hetian),in the north of the TP,under the condition of the dust-days and clear-days.The observation data was collected from 5 July to 4 August,2019.The mass concentration of dust(PM20)was measured with a 10-stage quartz crystal microbalance cascade impactor.The results suggested that 91.9%of the particles were less than 1.4μm on clear-days,and particles of d≥1.4μm increased to 27.2%with the occurrence of the dust events.More than 80%of the airborne dust particles were less than 1.4μm for each friction velocity.The proportion of d<0.7μm was the greatest at 3.0 m(above the surface,similarly hereinafter)on dust-days,while the proportion of d>0.7μm was the greatest at 0.5 m on clear-days.During urban observation,with the occurrence of dust events,the concentration of a particle size greater than 2.5μm increased most significantly in Minfeng,while the concentration of a particle size less than 0.7μm increased most significantly in Hetian.Moreover,the proportion of particles with d<0.7μm had the smallest difference,while the proportion of particles with d>1.4μm had the most obvious difference among these three sites.
基金The key project of the Ministry of Science and Technology of China, No.2004DKA20170-02
文摘Using foggy days and mean temperature and relative humidity data of 602 stations from January to December in the period 1961-2003 in China, the relationship between variations of foggy days and temperature and its possible reason for the 43 years were analyzed by regression, correlation and contrastive analysis methods. The results show that the higher (lower) the mean temperature and the lower (higher) the relative humidity correspond to less (more) foggy days, the relationship is the best in the western, northern and eastern Sichuan, Yunnan-Guizhon Plateau, and southeast highland in China. This induces a decrease in relative humidity when the climate becomes warmer, and eventually brings about a decrease in foggy days in China.
基金supported by Russian Foundation for Basic Research grants No. 17-05-00989, No. 16-05-00753,NRU HSE and visiting grants positions at Paris observatory and Wuhan university for the first authorpartially supported by grants by NSF/IGFA Belmont Forum Project (Grant No. ICER-1342644)the Chinese Academy of Sciences/SAFEA International Partnership Program for Creative Research Teams(Grant No. KZZD-EW-TZ-05)
文摘Earth's variable rotation is mainly produced by the variability of the AAM(atmospheric angular momentum). In particular, the axial AAM component X_3, which undergoes especially strong variations,induces changes in the Earth's rotation rate. In this study we analysed maps of regional input into the effective axial AAM from 1948 through 2011 from NCEP/NCAR reanalysis. Global zonal circulation patterns related to the LOD(length of day) were described. We applied MSSA(Multichannel Singular Spectrum Analysis) jointly to the mass and motion components of AAM, which allowed us to extract annual, semiannual, 4-mo nth, quasi-biennial, 5-year, and low-frequency oscillations. PCs(Principal components) strongly related to ENSO(El Nino southern oscillation) were released. They can be used to study ENSO-induced changes in pressure and wind fields and their coupling to LOD. The PCs describing the trends have captured slow atmospheric circulation changes possibly related to climate variability.
文摘We studied radial and inter-progeny variations in the dimen- sions of the wood elements and specific gravity of 21 half sib progenies of Populus deltoides Bartr. ex Marsh. The female parents of half sib progenies were G48 and $7C13 clones. Variance ratio (F) test indicated that inter-progeny variations in the dimensions of wood elements and specific gravity were significant for all wood traits while variations were significant for radial location for specific gravity only. Hierarchical clus- ter analysis was done by Squared Euclidean Distance for all of 21 proge- nies considering six wood traits. 21 progenies were grouped into 4 clus- ters. Cluster 1 was the largest cluster with 11 progenies, whereas cluster 3 had only one progeny. Selected progenies in clusters 3 (progeny 155, male) and 4 (progeny 108, 196, both female) were highly divergent from the other progenies so they were used in combinations as parents of hybrids to develop new clones with desired characters. Progeny 155 showed higher growth, fiber dimensions, and specific gravity, thus, should be used for the development of new clones.
文摘The induction of biofilm formation has been explored as a means of harvesting microalgae for bioprocessing applications. Environmental stressors have been implicated in the induction of biofilm formation;however, it is unclear whether all stressors, or a select few, are responsible. This study aimed to investigate the effects of three stressors, nitrogen depletion, reduced or elongated day lengths, and increased culture turbulence on bio-film formation of Parachlorella kessleri. We also examined corresponding effects on growth and production of reactive oxygen species. Turbulence induced the greatest response in which a significant decrease in growth plus an increase in superoxide production and flocculation efficiency were seen for the 300-rpm treatment. For varying day lengths, stress response was not observed, however, a significant increase in EPS secretion was measured in both shorter and longer days. Nitrogen depletion induced a low-level stress response, in which superoxide production increased for the highest concentrations, while growth was not impacted. In contrast to previous studies on nitrogen depletion, a significant increase in EPS secretion was not observed. Results indicate that stress response varies according to type and magnitude. EPS production and thus biofilm formation are not linked to the stress indicators investigated. P. kessleri uses small quantities of EPS to contribute to cell stickiness, but not necessarily to the full formation of a biofilm;however, cell stickiness served as a mechanism for substrate adherence and cellular aggregation none the less.
文摘The objective of the present study was to determine the optimum sowing time of three quinoa ecotypes (Altipllano, sea level, and valley) for high seed yields in south Kanto, Japan. Pot experiments were conducted in the experimental field at Nihon University during 2011, 2012, 2013, and 2014. In this experiment, the following quinoa varieties were used NL-6, Baer Cajon and Cauquenes (sea-level type), Amarilla de Marangani, Blanca de Junin, CICA-127, ECU-420, ECU-525, Ingapirica, and Narino (valley type), 94R and Isluga (Altiplano type). The quinoa seeds were sown on March 29, June 17 and September 22, 2011;March 27, June 17 and August 28, 2012;March 26, June 15 and 5 September 5, 2013;and March 27, June 17 and August 28, 2014. When the sea-level type and Altiplano type seeds were sowed from March to September, the seeds could be gained in all sowing plots. However, the seed weights of all varieties were the highest in the sowing plots of March. And the seed weights in the sowing plot of March were significantly higher than that in the other sowing plots. The sea-level type and Altiplano type quinoa had almost the same seed growth reaction for day length and day temperature. Thus, to gain a high seed yield of the sea-level and Altiplano type quinoa, March was the optimum sowing time in south Kanto, Japan. When the valley-type seeds were sowed from March to June, the seeds could not be gained, except in 2012. In 2012, the seed weights and seed numbers in sowing plots of March and June were significantly lower than those in the sowing plot of September. Thus, to obtain a high seed yield of the valley type quinoa, the optimum sowing time in south Kanto, Japan was from August to September.