[Objective] The countermeasure on the number of fructification of Spartina alterniflora in the period of sexual reproduction and the component of seed yielding construction was explored.[Method] The Spartina altemiflo...[Objective] The countermeasure on the number of fructification of Spartina alterniflora in the period of sexual reproduction and the component of seed yielding construction was explored.[Method] The Spartina altemiflora in Mangroves conservation zone located at Hepu of Guangxi being taken as experimental material, its morphological and quantitative characteristics, as well as the weight of 100 full seeds at maturity stage in three different growth conditions( clay, loam and sand) were studied. [ Results] The results showed that Spartina alterniflora had the best growth pattern in the loam. The morphological factors of fructification of S. altemiflora grown in sand were larger then in others. In the three growth conditions the order of quantitative characteristics of fructification of S. alterniflora was clay 〉 sand 〉 loam and the seeds in spikelet at top position were more maturity than those at the button position. [ Conclusion] In good condition, the Spartina altemiflora growth was vigor but the ratio of seed-setting was low.展开更多
[ Objective] To study the characteristics of florescence and pollen in Lagerstroemia speciosa. [ Method ] The process of flower opening and pollen tube germination of Lagerstroemia speciosa was observed and the pollen...[ Objective] To study the characteristics of florescence and pollen in Lagerstroemia speciosa. [ Method ] The process of flower opening and pollen tube germination of Lagerstroemia speciosa was observed and the pollen viability was determined through in vitro germination. [ Result] Sepals of L. speciosa started to diverge at 4:30 am, at 7: 00 am petals flatten up, anther diverged, and the stigma secreted a large number of mucus, it was the best time for artificial pollination. Boric acid and sucrose had a great effect on in vitro pollen germination of L. speciosa, the combination which made highest rate of pollen germination, was sucrose 150 g/L + boric acid 20 mg/L + CaCI2 10 mg/L. Through the fluorescence microscope, it was known that four hours after flowering, a lot of pollen grains germinated on the stigma, six hours after flowering, lots of pollen tubes entered the style and reached to 1/4 length of the style, 12 hours after flowering, pollen tubes concentrated into a beam forward, and reached to 1/2 length of the style, 24 hours after flowering, lots of pollen tubes entered the ovary in a beam and then fertilized and produced seeds. [ Conclusion] The results provide some basis for utilizing L. speciosa to breed.展开更多
Based on simulations of 18 CMIP5 models under three RCP scenarios, this article investigates changes in mean temperature and precipitation and their extremes over Asia in the context of global warming targets of 1.5-4...Based on simulations of 18 CMIP5 models under three RCP scenarios, this article investigates changes in mean temperature and precipitation and their extremes over Asia in the context of global warming targets of 1.5-4 ℃, and further compares the differences between 1.5 ℃ and 2 ℃ targets. Results show that relative to the pre-industrial era, the mean temperature over Asia increases by 2.3 ℃, 3.0 ℃, 4.6 ℃, and 6.0 ℃ at warming targets of 1.5 ℃, 2 ℃, 3 ℃, and 4 ℃, respectively, with stronger warming in high latitudes than in low latitudes. The corresponding enhancement in mean precipitation over the entire Asian region is 4.4%, 5.8%, 10.2%, and 13.0%, with significant regional differences. In addition, an increase in warm extremes, a decrease in cold extremes, and a strengthening in the variability of amounts of extreme precipitation are projected. Under the 1.5 ℃ target, compared with the climate under the 2 ℃ target, the mean temperature will be lower by 0.5-1 ℃ over Asia; the mean precipitation will be less by 5%-20% over most of Asia, but will be greater by about 10%-15% over West Asia and western South Asia; extreme high temperatures will be uniformly cooler throughout the Asian region, and the warming in extreme low temperatures will decrease significantly in high latitudes of Asia; extreme precipitation will be weaker over most of Asia but will be stronger over West Asia and western South Asia. Under the 1.5 ℃ and 2 ℃ warming targets, the probability of very hot weather (anomalies greater than 1σ, σ is standard deviation), extremely hot weather (anomalies greater than 3or), and extremely heavy precipitation (anomalies greater than 3σ) occurring will increase by at least once, 10%, and 10%, respectively, compared to the reference period (1861-1900).展开更多
Studying the relationship between climate factors and soil organic carbon (SOC) is vitally important. However, how SOC responses to climate (temperature and precipitation) at cohesive extents is poorly studied. Tw...Studying the relationship between climate factors and soil organic carbon (SOC) is vitally important. However, how SOC responses to climate (temperature and precipitation) at cohesive extents is poorly studied. Two transects of approximately the same length (transect P and transect T) were selected to examine the variation of SOC content in relation to mean annual temperature (MAT) and mean annual precipitation (MAP). The coefficients of partial correlation between SOC density and MAT (Rt) and MAP (Rp) were determined to quantify the relationships between SOC density and the two climate factors. The results indicated that for transect T, Rt was statistically significant once the extent level was greater than or equal to two fundamental extent units, while for transect P, Rp showed statistical significance only at extent levels which were greater than two fundamental extent traits. At the same extent levels but in different transects, Rts exhibited no zonal difference, but Rps did once the extent level was greater than two fundamental extent units. Therefore, to study the relationship between SOC density and different climate factors, different minimum extent levels should be ex- amined. The results of this paper could deepen the understanding of the impacts that SOC pool has on terrestrial ecosystem and global carbon cycling.展开更多
The purpose of this paper is to apply "LARS-WG (Long Ashton Research Station--Weather Generator)" model to simulate the climate change scenarios for Phu Luong watershed in northem Viet Nam. Results indicated that ...The purpose of this paper is to apply "LARS-WG (Long Ashton Research Station--Weather Generator)" model to simulate the climate change scenarios for Phu Luong watershed in northem Viet Nam. Results indicated that LARS-WG adequately predicted precipitation and temperature with R2 = 0.80 and 0.73, respectively. Likewise, p-value of F test = 0.062 and p-value of t test = 0.885 for precipitation, meanwhile, for temperature are 0.092 and 0.564 at 0.05 level of significance, respectively. Moreover, results also stated that mean annual precipitation increases 1.62%, 2.17% and 3.96% and mean annual temperature increases 0.6 ℃, 0.8 ℃ and 1.05 ℃ in 2020, 2030 and 2040, respectively, with respect to those from baseline periods. This study also showed that LARS-WG model was used successfully for Viet Nam's watershed conditions.展开更多
Based on the observations from 239 meteorological stations located in Central China (Henan, Hubei and Hunan provinces), this paper focuses on the climate change facts during 1961- 2010. There was a significant incre...Based on the observations from 239 meteorological stations located in Central China (Henan, Hubei and Hunan provinces), this paper focuses on the climate change facts during 1961- 2010. There was a significant increasing trend in annual mean temperature for Central China during 1961 -2010. The increasing rate was 0.15℃ per decade, which was lower than the national trend. Since the mid-1980s, temperature increasing was obvious. Large increasing rate was observed in the mid-eastern part of Central China. For the four seasons, the increasing rate in winter was the largest (0.27℃ per decade). The increasing rate in the annual mean minimum temperature was larger than that in the annual mean maximum temperature from 1961 to 2010. As a result, the diurnal range of temperature decreased at the rate of -0.10℃ per decade. The extreme high temperature events were increasing while the extreme low temperature events were significantly decreasing. There was no obvious trend in annual precipitation for Central China during 1961-2010. Precipitation in summer and winter significantly increased; change of precipitation in spring was not obvious; precipitation in autumn was decreasing. The decreasing rate of annual rainy days was -3.4 d per decade. The precipitation intensity increased at the rate of 0.25 mm d-1 per decade. Heavy-rain days significantly increased. Spring and summer started earlier while autumn and winter started later. As a result, spring and summer duration was expanding whereas autumn and winter duration shortened.展开更多
The agricultural soil carbon pool plays an important role in mitigating greenhouse gas emission ana unaerstanamg the son orgamc carbon-climate-soil texture relationship is of great significance for estimating cropland...The agricultural soil carbon pool plays an important role in mitigating greenhouse gas emission ana unaerstanamg the son orgamc carbon-climate-soil texture relationship is of great significance for estimating cropland soil carbon pool responses to climate change. Using data from 900 soil profiles, obtained from the Second National Soil Survey of China, we investigated the soil organic carbon (SOC) depth distribution in relation to climate and soil texture under various climate regimes of the cold northeast region (NER) and the warmer Huang-Huai-Hai region (HHHR) of China. The results demonstrated that the SOC content was higher in NER than in HHHR. For both regions, the SOC content at all soil depths had significant negative relationships with mean annual temperature (MAT), but was related to mean annual precipitation (MAP) just at the surface 0-20 cm. The climate effect on SOC content was more pronounced in NER than in HHHR. Regional differences in the effect of soil texture on SOC content were not found. However, the dominant texture factors were different. The effect of sand content on SOC was more pronounced than that of clay content in NER. Conversely, the effect of clay on SOC was more pronounced than sand in HHHR. Climate and soil texture jointly explained the greatest SOC variability of 49.0% (0-20 cm) and 33.5% (20-30 cm) in NER and HHHR, respectively. Moreover, regional differences occurred in the importance of climate vs. soil texture in explaining SOC variability. In NER, the SOC content of the shallow layers (0-30 cm) was mainly determined by climate factor, specifically MAT, but the SOC content of the deeper soil layers (30-100 cm) was more affected by texture factor, specifically sand content. In HHHR, all the SOC variability in all soil layers was predominantly best explained by clay content. Therefore, when temperature was colder, the climate effect became stronger and this trend was restricted by soil depth. The regional differences and soil depth influence underscored the importance of explicitly considering them in modeling long-term soil responses to climate change and predicting potential soil carbon sequestration.展开更多
基金Supported by the National Natural Science Foundation of China(30660036 )the Natural Science Foundation of Guangxi Province(0728096) Project of Graduate Student Education Innovation ofGuangxi (2008106020907M266)~~
文摘[Objective] The countermeasure on the number of fructification of Spartina alterniflora in the period of sexual reproduction and the component of seed yielding construction was explored.[Method] The Spartina altemiflora in Mangroves conservation zone located at Hepu of Guangxi being taken as experimental material, its morphological and quantitative characteristics, as well as the weight of 100 full seeds at maturity stage in three different growth conditions( clay, loam and sand) were studied. [ Results] The results showed that Spartina alterniflora had the best growth pattern in the loam. The morphological factors of fructification of S. altemiflora grown in sand were larger then in others. In the three growth conditions the order of quantitative characteristics of fructification of S. alterniflora was clay 〉 sand 〉 loam and the seeds in spikelet at top position were more maturity than those at the button position. [ Conclusion] In good condition, the Spartina altemiflora growth was vigor but the ratio of seed-setting was low.
基金Supported by the National Key Technology R&D Program in EleventhFive-Year Plan of China(2006BAD01A18)the Program fromMinistry of Environmental Protection of China(Species09-2-3-1)~~
文摘[ Objective] To study the characteristics of florescence and pollen in Lagerstroemia speciosa. [ Method ] The process of flower opening and pollen tube germination of Lagerstroemia speciosa was observed and the pollen viability was determined through in vitro germination. [ Result] Sepals of L. speciosa started to diverge at 4:30 am, at 7: 00 am petals flatten up, anther diverged, and the stigma secreted a large number of mucus, it was the best time for artificial pollination. Boric acid and sucrose had a great effect on in vitro pollen germination of L. speciosa, the combination which made highest rate of pollen germination, was sucrose 150 g/L + boric acid 20 mg/L + CaCI2 10 mg/L. Through the fluorescence microscope, it was known that four hours after flowering, a lot of pollen grains germinated on the stigma, six hours after flowering, lots of pollen tubes entered the style and reached to 1/4 length of the style, 12 hours after flowering, pollen tubes concentrated into a beam forward, and reached to 1/2 length of the style, 24 hours after flowering, lots of pollen tubes entered the ovary in a beam and then fertilized and produced seeds. [ Conclusion] The results provide some basis for utilizing L. speciosa to breed.
基金Acknowledgments This research was jointly supported by the National Key Research and Development Program of China (2016YFA0600701), the National Natural Science Foundation of China (41675069), and the Climate Change Specific Fund of China (CCSF201731).
文摘Based on simulations of 18 CMIP5 models under three RCP scenarios, this article investigates changes in mean temperature and precipitation and their extremes over Asia in the context of global warming targets of 1.5-4 ℃, and further compares the differences between 1.5 ℃ and 2 ℃ targets. Results show that relative to the pre-industrial era, the mean temperature over Asia increases by 2.3 ℃, 3.0 ℃, 4.6 ℃, and 6.0 ℃ at warming targets of 1.5 ℃, 2 ℃, 3 ℃, and 4 ℃, respectively, with stronger warming in high latitudes than in low latitudes. The corresponding enhancement in mean precipitation over the entire Asian region is 4.4%, 5.8%, 10.2%, and 13.0%, with significant regional differences. In addition, an increase in warm extremes, a decrease in cold extremes, and a strengthening in the variability of amounts of extreme precipitation are projected. Under the 1.5 ℃ target, compared with the climate under the 2 ℃ target, the mean temperature will be lower by 0.5-1 ℃ over Asia; the mean precipitation will be less by 5%-20% over most of Asia, but will be greater by about 10%-15% over West Asia and western South Asia; extreme high temperatures will be uniformly cooler throughout the Asian region, and the warming in extreme low temperatures will decrease significantly in high latitudes of Asia; extreme precipitation will be weaker over most of Asia but will be stronger over West Asia and western South Asia. Under the 1.5 ℃ and 2 ℃ warming targets, the probability of very hot weather (anomalies greater than 1σ, σ is standard deviation), extremely hot weather (anomalies greater than 3or), and extremely heavy precipitation (anomalies greater than 3σ) occurring will increase by at least once, 10%, and 10%, respectively, compared to the reference period (1861-1900).
基金Under the auspices of Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues of Chinese Academy of Sciences(No.XDA05050503)National Key Technology Research and Development Program of China(No.2013BAD11B00)National Natural Science Foundation of China(No.41301242)
文摘Studying the relationship between climate factors and soil organic carbon (SOC) is vitally important. However, how SOC responses to climate (temperature and precipitation) at cohesive extents is poorly studied. Two transects of approximately the same length (transect P and transect T) were selected to examine the variation of SOC content in relation to mean annual temperature (MAT) and mean annual precipitation (MAP). The coefficients of partial correlation between SOC density and MAT (Rt) and MAP (Rp) were determined to quantify the relationships between SOC density and the two climate factors. The results indicated that for transect T, Rt was statistically significant once the extent level was greater than or equal to two fundamental extent units, while for transect P, Rp showed statistical significance only at extent levels which were greater than two fundamental extent traits. At the same extent levels but in different transects, Rts exhibited no zonal difference, but Rps did once the extent level was greater than two fundamental extent units. Therefore, to study the relationship between SOC density and different climate factors, different minimum extent levels should be ex- amined. The results of this paper could deepen the understanding of the impacts that SOC pool has on terrestrial ecosystem and global carbon cycling.
文摘The purpose of this paper is to apply "LARS-WG (Long Ashton Research Station--Weather Generator)" model to simulate the climate change scenarios for Phu Luong watershed in northem Viet Nam. Results indicated that LARS-WG adequately predicted precipitation and temperature with R2 = 0.80 and 0.73, respectively. Likewise, p-value of F test = 0.062 and p-value of t test = 0.885 for precipitation, meanwhile, for temperature are 0.092 and 0.564 at 0.05 level of significance, respectively. Moreover, results also stated that mean annual precipitation increases 1.62%, 2.17% and 3.96% and mean annual temperature increases 0.6 ℃, 0.8 ℃ and 1.05 ℃ in 2020, 2030 and 2040, respectively, with respect to those from baseline periods. This study also showed that LARS-WG model was used successfully for Viet Nam's watershed conditions.
基金supported by the Climate Change Special Project of China Meteorological Administration:The Assessment Report Preparation of the Climate Change of Central China (No. CCSF-10-04)
文摘Based on the observations from 239 meteorological stations located in Central China (Henan, Hubei and Hunan provinces), this paper focuses on the climate change facts during 1961- 2010. There was a significant increasing trend in annual mean temperature for Central China during 1961 -2010. The increasing rate was 0.15℃ per decade, which was lower than the national trend. Since the mid-1980s, temperature increasing was obvious. Large increasing rate was observed in the mid-eastern part of Central China. For the four seasons, the increasing rate in winter was the largest (0.27℃ per decade). The increasing rate in the annual mean minimum temperature was larger than that in the annual mean maximum temperature from 1961 to 2010. As a result, the diurnal range of temperature decreased at the rate of -0.10℃ per decade. The extreme high temperature events were increasing while the extreme low temperature events were significantly decreasing. There was no obvious trend in annual precipitation for Central China during 1961-2010. Precipitation in summer and winter significantly increased; change of precipitation in spring was not obvious; precipitation in autumn was decreasing. The decreasing rate of annual rainy days was -3.4 d per decade. The precipitation intensity increased at the rate of 0.25 mm d-1 per decade. Heavy-rain days significantly increased. Spring and summer started earlier while autumn and winter started later. As a result, spring and summer duration was expanding whereas autumn and winter duration shortened.
基金Supported by the National Natural Science Foundation of China(No.40921061)the"Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues"of Chinese Academy of Sciences(No.XDA05050509)the National Basic Research Program(973 Program)of China(No.2010CB950702)
文摘The agricultural soil carbon pool plays an important role in mitigating greenhouse gas emission ana unaerstanamg the son orgamc carbon-climate-soil texture relationship is of great significance for estimating cropland soil carbon pool responses to climate change. Using data from 900 soil profiles, obtained from the Second National Soil Survey of China, we investigated the soil organic carbon (SOC) depth distribution in relation to climate and soil texture under various climate regimes of the cold northeast region (NER) and the warmer Huang-Huai-Hai region (HHHR) of China. The results demonstrated that the SOC content was higher in NER than in HHHR. For both regions, the SOC content at all soil depths had significant negative relationships with mean annual temperature (MAT), but was related to mean annual precipitation (MAP) just at the surface 0-20 cm. The climate effect on SOC content was more pronounced in NER than in HHHR. Regional differences in the effect of soil texture on SOC content were not found. However, the dominant texture factors were different. The effect of sand content on SOC was more pronounced than that of clay content in NER. Conversely, the effect of clay on SOC was more pronounced than sand in HHHR. Climate and soil texture jointly explained the greatest SOC variability of 49.0% (0-20 cm) and 33.5% (20-30 cm) in NER and HHHR, respectively. Moreover, regional differences occurred in the importance of climate vs. soil texture in explaining SOC variability. In NER, the SOC content of the shallow layers (0-30 cm) was mainly determined by climate factor, specifically MAT, but the SOC content of the deeper soil layers (30-100 cm) was more affected by texture factor, specifically sand content. In HHHR, all the SOC variability in all soil layers was predominantly best explained by clay content. Therefore, when temperature was colder, the climate effect became stronger and this trend was restricted by soil depth. The regional differences and soil depth influence underscored the importance of explicitly considering them in modeling long-term soil responses to climate change and predicting potential soil carbon sequestration.