基于微米级液滴的低温等离子体水基固氮与雾培应用

针对氮肥的生产问题,提出了一种新型人工固氮方案,该方案基于纳秒脉冲等离子体技术,微米级雾滴在通过空气等离子体的过程中,形成了含有NH_(4)^(+)、NO_(3)^(-)、NO_(2)^(-)和其他活性物质的等离子体活化雾(PAM)。该系统采用自制的纳秒脉冲电源供电,可由功率为200 W的太阳能电池板驱动,在此条件下,产出以NO_(3)^(-)为主的液相固氮产物,其固氮能耗仅为48.67 MJ/mol。为验证该系统的固氮效果,将其与自主设计的雾培系统相结合,将含氮营养物质直接输送到植物的根部。结果显示,该方案使豆芽的叶片生叶率显著提高,叶片面积增加了30%以上。相比于传统实验室规模的等离子体反应器,该装置在时间尺度上具有更高的能量密度,在空间尺度上具有更大的反应面积,这大大降低了固氮的能耗。新型人工固氮方案具有低能耗、可扩展、可接入清洁可再生能源的特点,有望实现可持续生产和分布式应用。

ABT1号生根粉对藤稔葡萄扦插成苗的影响

不同含量ABT 1号生根粉处理藤稔葡萄插条的扦插试验结果表明 ,5 0～ 1 5 0mg/kg的ABT 1号生根粉对插条生根长叶均有促进作用。其中 1 0 0mg/kg处理的生根率和生叶率最高 ,分别为 88%和 80 % ;1 2 5mg/kg处理的插条其生根数和生叶数最多 ,分别为 2 1 .1 4条和 3.5 6片。另外 ,1 2 5mg/kg处理的单株根鲜重、叶鲜重分别为 0 .845 2 g和 1 .5 71 0 g ,均极显著高于对照。

Stem Respiration of a Larch (Larix gmelini) Plantation in Northeast China

Stem respiration is an important part of the activity of a tree and is an important source of CO2 evolution from a forest ecosystem. Presently, no standard methods are available for the accurate estimation of total stem CO2 efflux from a forest. In the current study, a 33-year-old (by the year 2001) larch (Larix gmelini Rupr.) plantation was measured throughout 2001-2002 to analyze its monthly and seasonal patterns of stem respiration. Stem respiration rate was also measured at different heights, at different daily intervals and any variation in the larch plantation was recorded. The relationship between stem temperature, growth status and respiration rate was analyzed. Higher respiration rates were recorded in upper reaches of the larch tree throughout the season and these were affected partially by temperature difference. Midday depression was found in the diurnal changes in stem respiration. In the morning, but not in the afternoon, stem respiration was positively correlated with stem temperature. The reason for this variation may be attributed to water deficit, which was stronger in the afternoon. In the larch plantation, a maximum 7-fold variation in stem respiration was found. The growth status (such as mean growth rate of stem and canopy projection area) instead of stem temperature difference was positively correlated with this large variation. An S-model (sigmoid curve) or Power model shows the greatest regression of the field data. In the courses of seasonal and annual changes of stem respiration, peak values were observed in July of both years, but substantial interannual differences in magnitude were observed. An exponential model can clearly show this regression of the temperature-respiration relationship. In our results, Q(10) values ranged from 2.22 in 2001 to 3.53 in 2002. Therefore, estimation of total stem CO2 efflux only by a constant Q(10) value may give biased results. More parameters of growth status and water status should be considered for more accurate estimation.

Response of seedlings of different tree species to elevated CO_2 in Changbai Mountain

Eco-physiological responses of seedlings of eight species, Pinus koraiensis, Picea koraiensis, Larix olgensis, Populus ussuriensis, Betula platyphylla, Tilia amurensis, Traxinus mandshurica and Acer mono from broadleaved/Korean pine forest, to elevated CO2 were studied by using open-top chambers under natural sunlight in Changbai Mountain, China in two growing seasons (1998-1999). Two concentrations of CO2 were designed: elevated CO2 (700 祄olmol-1) and ambient CO2 (400 祄olmol-1). The study results showed that the height growth of the tree seedlings grown at elevated CO2 increased by about 10%-40% compared to those grown at ambient CO2. And the water using efficiency of seedlings also followed the same tendency. However, the responses of seedlings in transpiration and chlorophyll content to elevated CO2 varied with tree species. The broad-leaf tree species were more sensitive to the elevated CO2 than conifer tree species. All seedlings showed a photosynthetic acclimation to long-term elevated CO2.

Effect of microbial inoculants on Albizia saman germination and seedling growth

Microbial Inoculants as Effective Microorganisms （EM） were applied to find out their effects on germination and seedling growth of Albizia saman in the nursery. The seedlings were grown in a mixture of sandy soils and cow dung （3：1） kept in polybags. The EM solution at different concentrations （0.1%, 0.5%, 1%, 2%, 5% and 10%） was incorporated before and after a week of sowing seeds. Germination and physical growth parameters, including shoot and root length, vigor index, collar diameter, leaf number, fresh and dry weight of shoot and root and total biomass increment over the control were measured. The nodulation status influenced by EM was also observed along with the estimation of chemical parameters like chlorophyll a, chlorophyll b and carotenoid. Both germination and the measured physical growth parameters were found significantly （P〈0.05） higher in seedlings treated with different concentrations of EM solution in comparison to the control. Maximum growth was found at 2% followed by 1% EM solution. Nodulation was higher at 0.1% concentration but it normally decreased with the increase of concentrations. Although there were a higher amount of pigments in leaves of the treated seedlings than of the control, the variations recorded with respect to chlorophyll a, b and carotenoid were not significantly higher in most of the treatments. Treated seedlings showed variable results along with the increment of EM applications and most of the parameters showed best results at the medium range of concentrations. The study indicates that the Microbial Inoculant （EM） technology might be useful to improve the growth of seedlings in the nursery. This also indicates that the associated beneficial organisms along with the polybag soils might be of value in improving the degraded soil or poor field soil for better nutrient and water uptake during the initial growth of transplanted seedlings.

Effects of salinity and nutrients on the growth and chlorophyll fluorescence of Caulerpa lentillifera

Caulerpa lentillifera is a green algae that distributes worldwide and is cultivated for food. We assessed vegetative propagation of C. lentillifera by measuring the specific growth rate （SGR） and chlorophyll fluorescence of the green algae cultured at different salinities and nutrient levels. The results indicated that C. lentillifera can survive in salinities ranging from 20 to 50, and can develop at salinities of 30 to 40. The maximum SGR for C. lentillifera occurred at a salinity of 35. Both chlorophyll content and the ratio of variable to maximum fluorescence （F_v/F_m） were also at a maximum at a salinity of 35. Photosynthesis was inhibited in salinities greater than 45 and less than 25. Both the maximum SGR and maximum chlorophyll content were found in algae treated with a concentration of 0.5 mmol/L of NO3-N and 0.1 mmol/L of PO_4-P. The photosynthetic capacity of photosystem Ⅱ （PSⅡ） was inhibited in cultures of C. lentillifera at high nutrient levels. This occurred when NO_3-N concentrations were greater than 1.0 mmol/L and when PO4-P concentrations were at 0.4 mmol/L. As there is strong need for large-scale cultivation of C. lentillifera, these data contribute important information to ensure optimal results.

Effect of climate change on seasonal water use efficiency in subalpine Abies fabri

Abies fabri is a typical subalpine dark coniferous forest in southwestern China. Air temperature increases more at high elevation areas than that at low elevation areas in mountainous regions,and climate change ratio is also uneven in different seasons. Carbon gain and the response of water use efficiency(WUE) to annual and seasonal increases in temperature with or without CO_2 fertilization were simulated in Abies fabri using the atmospheric-vegetation interaction model(AVIM2). Four future climate scenarios(RCP2.6,RCP4.5,RCP6.0 and RCP8.5) from the Coupled Model Intercomparison Project Phase 5(CMIP5) were selectively investigated. The results showed that warmer temperatures have negative effects on gross primary production(GPP) and net primary production(NPP) in growing seasons and positive effects in dormant seasons due to the variation in the leaf area index. Warmer temperatures tend to generate lower canopy WUE and higher ecosystem WUE in Abies fabri. However,warmer temperature together with rising CO_2 concentrations significantlyincrease the GPP and NPP in both growing and dormant seasons and enhance WUE in annual and dormant seasons because of the higher leaf area index(LAI) and soil temperature. The comparison of the simulated results with and without CO_2 fertilization shows that CO_2 has the potential to partially alleviate the adverse effects of climate warming on carbon gain and WUE in subalpine coniferous forests.

Bayesian mapping of neural tube defects prevalence in Heshun County, Shanxi Province, China during 1998～2001

Objective: To estimate the prevalence rates of neural tube defects (NTDs) in Heshun County, Shanxi Province, China by Bayesian smoothing technique. Methods: A total of 80 infants in the study area who were diagnosed with NTDs were analyzed. Two mapping techniques were then used. Firstly, the GIS software ArcGIS was used to map the crude prevalence rates. Secondly, the data were smoothed by the method of empirical Bayes estimation. Results: The classical statistical approach produced an extremely dishomogeneous map, while the Bayesian map was much smoother and more interpretable. The maps produced by the Bayesian technique indicate the tendency of villages in the southeastern region to produce higher prevalence or risk values. Conclusions: The Bayesian smoothing technique addresses the issue of heterogeneity in the population at risk and it is therefore recommended for use in explorative mapping of birth defects. This approach provides procedures to identify spatial health risk levels and assists in generating hypothesis that will be investigated in further detail.

Adjuvant chemoradiotherapy versus surgery alone for gastric adenocarcinoma

Objective:Despite resection with curative intent,a majority of patients with gastric cancer will develop disease recurrence.Postoperative adjuvant chemo-radiotherapy increase the curability of surgery,prevent local recurrence and improve survival.Methods:Between December 2005 and February 2010,33 patients were eligible for the study,17 patients were randomly assigned for chemo-radiotherapy (GI) and 16 patients with surgery alone (GII).Patients in GI received chemotherapy (fluorouracil,425 mg/m 2/day,and leucovorin,20 mg/m 2/day,for 5 days) was initiated on day 1 and was followed by chemo-radiotherapy beginning 28 days after the start of the initial cycle of chemotherapy.Chemo-radiotherapy consisted of 4500 cGy of radiation at 180 cGy/day,five days/week for five weeks,with fluorouracil (400 mg/m 2/day) and leucovorin (20 mg/m 2/day) on the first four and the last four days of radiotherapy.One month after the completion of radiotherapy,two five-day cycles of fluorouracil (425 mg/m 2/day) plus leucovorin (20 mg/m 2/day) were given one month apart.Results:Grade 3 gastrointestinal toxicity was more common (23.2%) while grade 3 hematological toxicity were (5.8%).Both 3-year survival (53%) and disease free survival (41%) rates were higher in GI than in GII in which they were 43.7% and 31% respectively.Relapse rate was higher in GII (56.3%) than in GI (35.3%).Conclusion:The present study revealed that chemo-radiotherapy after gastric resection in patients with gastric adenocarcinoma improves survival and relapse rates with manageable toxicities.However,studies with larger number of patients are recommended to confirm our results.

Reduction in Fertility by Nerium indicum Leaves Extract in Adults of Red Flour Beetle, Tribofium castaneum （Coleoptera： Tenebrionidae） Compared with Coopex （Bioallethrin： Permethrin）

Recent trend for the control of insect pests has been towards the use of substances of plant origin. Reductionin fertility was determined in red flour beetle, Tribolium castaneum （Herbst.） by Nerium indicum Millleaves extract compared with coopex applied by contact method under laboratory condition. When adults were placed on filter paper treated With 7.86, 9.43, 11.01, 12.58 and 14.15 μL/cm2 doses of N. indicum leaves extract, fertility was 154 ± 15.2, 139 ± 15.0, 126 ± 6.0, 89 ± 12.2 and 72 ± 13.6 larvae/pair, compared with untreated and controls fertility （233 ± 16.0 and 190 ± 15.1 larvae/pair, respectively）. However, the reduction in fertility was 33.2 ± 6.4%, 39.7 ± 3.7%, 45.7 ± 2.9%, 58.0 ± 4.4% and 66.3 ± 5.1% by the same doses ofN. indicum extract. Moreover, adults treated with the same doses of coopex with the same method, fertility was 160 ± 14.6, 154 ± 9.3, 140 ± 11.2, 113 ± 7.5 and 71 ±- 4.8 larvae/pair, compared with controls fertility （211 ± 8.5 larvae/pair）, respectively. Furthermore, reduction in fertility was 24.3 ± 5.2%, 30.2 ± 6.4%, 37.2 ± 8.0%, 51.3 ± 1.4% and 58.8 ± 4.7% by the same doses of coopex. Minimum fertility was found in August and maximum was in July in both, N. indicum extract and coopex treated batches. The trend of reduction in fertility was the same in both N. indicum leaves extract and coopex, i.e., it was increased gradually from lower to higher doses. Nerium indicum leaves extract reduced fertility significantly compared with coopex.

Quantifying biochemical variables of corn by hyperspectral reflectance at leaf scale

To further develop the methods to remotely sense the biochemical content of plant canopies,we report the results of an experiment to estimate the concentrations of three biochemical variables of corn,i.e.,nitrogen(N),crude fat(EE) and crude fiber(CF) concentrations,by spectral reflectance and the first derivative reflectance at fresh leaf scale. The correlations between spectral reflectance and the first derivative transformation and three biochemical variables were analyzed,and a set of estimation models were established using curve-fitting analyses. Coefficient of determination(R2),root mean square error(RMSE) and relative error of prediction(REP) of estimation models were calculated for the model quality evaluations,and the possible opti-mum estimation models of three biochemical variables were proposed,with R2 being 0.891,0.698 and 0.480 for the estimation models of N,EE and CF concentrations,respectively. The results also indicate that using the first derivative reflectance was better than using raw spectral reflectance for all three biochemical variables estimation,and that the first derivative reflectances at 759 nm,1954 nm and 2370 nm were most suitable to develop the estimation models of N,EE and CF concentrations,respectively. In addition,the high correlation coefficients of the theoretical and the measured biochemical parameters were obtained,especially for nitrogen(r=0.948).

A field study on the conversion ratio of phytoplankton biomass carbon to chlorophyll-a in Jiaozhou Bay,China

A one-year field study was conducted to determine the conversion ratio of phytoplankton biomass carbon （Phyto-C） to chlorophyll-a （Chl-a） in Jiaozhou Bay, China. We measured suspended particulate organic carbon （POC） and phytoplankton Chl-a samples collected in surface water monthly from March 2005 to February 2006. The temporal and spatial variations of Chl-a and POC concentrations were observed in the bay. Based on the field measurements, a linear regression model Ⅱwas used to generate the conversion ratio of Phyto-C to Chl-a. In most cases, a good linear correlation was found between the observed POC and Chl-a concentrations, and the calculated conversion ratios ranged from 26 to 250 with a mean value of 56 μg ·μl^-1. The conversion ratio in the fall was higher than that in the winter and spring months, and had the lowest values in the summer. The ratios also exhibited spatial variations, generally with low values in the near shore regions and relatively high values in offshore waters. Our study suggests that temperature was likely to be the main factor influencing the observed seasonal variations of conversion ratios while nutrient supply and light penetration played important roles in controlling the spatial variations.

Preliminary Investigation on Somatic Embryogenesis from Immature Cotyledon Explants of Shea （Vitellaria paradoxa G,）

Long juvenile phase and lack of effective protocols for large scale vegetative propagation are limitations to domestication and improvement of the shea tree. The present study seeks to develop a protocol for plant regeneration of shea （Vitellaria paradoxa） from immature cotyledon explants. Embryogenic callus cultures were induced on Murashige and Skoog medium （MS） containing 3% sucrose, 0.24% Phytagel, and various concentrations of 2,4-Dichlorophenoxyacetic acid （2,4-D） after four weeks of culture in darkness. Rates of embryogenic callus induction were significantly affected by the addition of 2, 4-D to the medium. Within 28 days of culture, the highest percentage of embyogenic calli （77.61%） occurred on MS media containing 0.45 ~tM of 2,4-D in the dark. Somatic embryos were obtained by culturing embryogenic callus （in the dark） on MS medium fortified with 3% sucrose, 0.24% phytagel and devoid of growth regulators. Culturing at 16 h photoperiod restricted both the induction of embryogenic calli cultures and somatic embryos. Somatic embryos germinated, developed shoots and rooted vigorously on MS medium devoid of growth regulators. Germinated plantlets were acclimatized, successfully.

Relative position of seeds driven the seedling growth are mediated by root-leaf traits

Variations in plant traits are indicative of plant adaptations to forest environments,and studying their relationships with tree growth provides valuable insights into forest regeneration.The spatial arrangement of plant seeds within the forest litter or soil critically infuences the variations of root-leaf traits,thereby affecting the adaptive strategies of emerging seedlings.However,our current understanding of the impacts of individual root-leaf traits on seedling growth in different relative position,and whether these traits together affect growth,remains limited.This study focuses on the dominant tree species,Castanopsis kawakamii,within the Sanming C.kawakamii Nature Reserve of China.The present experiment aimed to examine the variations in root-leaf traits of seedling,focus on the relative positions of seeds within different layers:beneath or above the litter layer,or within the bare soil layer(without litter).Our fndings provided evidence supporting a coordinated relationship between root and leaf traits,wherein leaf traits varied in conjunction with root traits in the relative positions of seeds.Specifcally,we observed that seedlings exhibited higher values for specifc leaf area and average root diameter,while displaying lower root tissue density.The mixed model explained 86.1%of the variation in root-leaf traits,surpassing the variation explained by the relative positions.Furthermore,soil nitrogen acted as a mediator,regulating the relationship between seedling growth and root-leaf traits,specifcally leaf dry matter content and root tissue density.Therefore,future studies should consider artifcially manipulating tree species diversity based on root-leaf traits characteristics to promote forest recovery.

Assessment and analysis of microwave emissivity and transmissivity of a deciduous forest towards the estimate of vegetation biomass

Forests play an important role in the global carbon cycle and have a potential impact on global climatic change.Monitoring forest biomass is of considerable importance in understanding the hydrological cycle.Because of the problem of dense forest cover,no reliable method with which to retrieve soil moisture in forest areas from the microwave emission signature has been established.All of these issues relate to the microwave emissivity and transmissivity characteristics of a forest.The microwave emission contribution received by a sensor above a forest canopy comes from both the soil surface and the vegetation layer.To analyze the relationship of forest biomass and forest emission and transmissivity,a high-order emission model,the matrix-doubling model,which consists of both soil and vegetation models,was developed and then validated for a young deciduous forest stand in a field experiment.To simulate the emissivity and transmissivity of a deciduous forest in the L and X bands using the matrix-doubling model,the parameters of components of deciduous trees when the leaf area index varies from 1 to10 were generated by an L-system and a forest growth model.The emissivity and transmissivity of a forest and the relationships of these parameters to forest biomass are presented and analyzed in this paper.Emissivity in the L band when the leaf area index is less than 6 and at viewing angles less than 40°,and transmissivity in the L band are the most sensitive parameters in deciduous forest biomass estimation.