基于MaxEnt模型的不同气候情景下白蜡树中国适生区预测

白蜡树自然分布主要在中国境内，而且也是中国栽培悠久的经济树种，研究其当前和历史的地理分布格局、未来气候条件下的地理分布格局及分布区的宏观动态变化，皆有重要意义。依据采集标本记录的183个分布点和21个环境因子，利用最大熵原理，对10种气候情景下白蜡树在中国的适生分布区及分布区的几何质心进行预测。结果表明:1）最大熵模型模拟效果较高，模拟10次，AUC值=0.915 0±0.005，故可用模型计算出的潜在分布区来预测适生分布区，并基本确定白蜡树的地理分布格局。2）年均温、温度季节变化方差、暖季降雨量和未定义坡度是影响白蜡树适生分布的主导因子。3）根据模型计算出的概率值进行分级得知，白蜡树在当前气候情景下的适生分布范围大概率（0.6<P<最大阈值）位于甘肃、陕西2省交界处，西南腹地（尤其是贵州省），河北、北京、安徽、江苏、浙江的一些地区亦可能分布。4）10种气候情景下白蜡树适生分布区的几何质心皆位于湖北省境内。由适生分布区面积的变化得知，自全新世中期至今白蜡树的适生面积减少约20%，未来高排放浓度场景下其适生分布区面积较当前分布区面积减少得最多。可见，白蜡树在我国适生分布区面积可能呈现缩减趋势，应对其进行保护与合理栽植。     

南方双季稻区不同复种方式对稻田综合温室效应的影响

为明确南方双季稻区不同复种方式对稻田综合温室效应和温室气体排放强度的影响,试验设置油菜-一季中稻(R-MR)、冬季绿肥(紫云英)-早稻-晚稻(GM-ER-LR)、冬闲-早稻-晚稻(WF-ER-LR)3个处理,采用静态暗箱-气相色谱法监测周年温室气体排放,探明不同复种方式对周年作物产量、稻田全球增温潜势(GWP)、籽粒能量产出(GEY)和全球增温潜势强度(GWPI)的影响。结果表明,与R-MR相比,GM-ER-LR和WF-ER-LR显著增加了CH₄累积排放量(分别提高1.27倍和1.18倍),显著降低了N₂O累积排放总量(分别降低34.1%和49.4%),GM-ER-LR和WF-ER-LR的CH₄和N₂O累积排放量无显著差异。与R-MR相比,GM-ER-LR和 WF-ER-LR显著提高了周年GEY(分别提高28.6%和27.0%)。在100年时间尺度上,GM-ER-LR和WF-ER-LR的稻田GWP分别是R-MR的1.27倍和1.18倍,GWPI分别较R-MR提高100%和50%。因此,GM-ER-LR和WF-ER-LR有利于提高作物产量,但会增加稻田综合温室效应和温室气体排放强度。鉴于双季稻区中稻面积有增大的趋势,综合环境效益和经济效益,油菜-一季中稻减排增效效果更好。     

温度和氯化钙对多年生黑麦草种子萌发的影响

为探索石灰岩地区多年生黑麦草(Lolium perenne)对高钙生长环境的生态适应性,本研究用多年生黑麦草的种子进行萌发试验,通过设置不同温度和不同浓度的氯化钙处理,探究温度和氯化钙对黑麦草种子萌发的影响。结果表明:同一温度下,低浓度(≤1.5%)氯化钙处理的黑麦草种子发芽率、发芽势和发芽指数普遍较高,而高浓度(≥2.0%)的氯化钙对其则有显著抑制作用(P<0.05)。低浓度氯化钙处理时,温度对多年生黑麦草萌发几乎无影响,高浓度氯化钙处理时,15℃/25℃为多年生黑麦草萌发的最适温度。研究结果不仅丰富了黑麦草生态适应性方面的研究,也为石灰岩地区生态恢复、土地利用以及水土保持提供理论依据。     

生物农药在柞蚕病害防治中的应用现状分析

概述了生物农药的种类、特点及其研究现状,介绍了利用微生物防治蚕病的研究进展,分析了微生物农药在柞蚕病害防治中的应用前景。     

Effects of postharvest treatments on recovery of Xanthomonas citri subsp. citri in infected grapefruit leaves

Studies were conducted to evaluate treatments that reduce recovery of Xanthomonas citri subsp. citri (Xcc) in infected grapefruit leaves. To investigate effects of temperature (0, 10, 40, and 50 °C), disinfectant (none or Pro-San), and treatment duration (0, 2, 10, and 20 min) on survival of Xcc in vitro, a split–split plot experimental design was utilized. Recovery of Xcc in vitro in the absence of Pro-San decreased with increasing treatment duration at 50 °C but not at temperatures <50 °C. Xcc in vitro was not detected after any treatment combination involving Pro-San. Decontamination of grapefruit leaves infected with Xcc in relation to disinfectant (none or Pro-San), temperature (0, 10, 40, 45, and 50 °C), treatment duration (0, 2, 5, 10, and 20 min), and assessment time (0, 2, 7, and 14 days post treatment [dpt]) was examined using a split–split–split plot design. Reductions in Xcc recovery generally increased with increasing treatment duration and temperature, and they were greater for treatments involving Pro-San. To examine the general trend of increased Xcc recovery with increasing dpt, nonlinear mixed regression analysis was used to fit a monomolecular model to relative Xcc recovery data. Results indicated that increases in relative Xcc recovery after 14 dpt were insignificant and unsubstantial. Treatment at 45 °C for 20 min or 50 °C for ≥5 min resulted in leaf tissue damage in some instances; in two cases, tissue damage was observed on untreated leaves 14 dpt. Experiments were conducted to investigate the relationships of tissue damage with leaf age and location of tissue damage in relation to point of inoculation. Tissue damage was observed on only the youngest, most supple leaves, and its localization did not appear to be related to naturally occurring citrus canker lesions or artificial inoculation sites. Results from these studies may be useful in formulation of future regulatory policies regarding trade of citrus foliage, especially those used as condiments.     

Expression and role of TRPM2 in H9N2 swine influenza virus infection-induced mouse pulmonary microvascular endothelial cell damage

AIM: To investigate the expression and role of transient receptor potential cation channel M2 (TRPM2) in H9N2 swine influenza virus (H9N2-SIV) infection-induced mouse pulmonary microvascular endothelial cell (PMEVC) damage. METHODS: At 24 h and 48 h after PMEVC (3 parallel test in each group) was infected by H9N2-SIV, the superoxide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) activity, reactive oxygen species (ROS) level and nitric oxide synthase (NOS) activity were measured according to the manufacturer's instructions. The ultrastructural changes of PMVEC were observed under electron microscope. Transendothelial electrical resistance (TEER) and the percentage of horse radish peroxidase (HRP) influx was measure by Transwell culture. The expression of TRPM2 at mRNA and protein levels was determined by real-time PCR and Western blot. The apoptosis of PMVEC was observed with Annexin V/PI staining. RESULTS: The SOD and GSH levels were decreased significantly in H9N2-SIV-infected PMEVC as compared with control group(P<0.05). However, NOS activity and ROS level were increased dramatically (P<0.01). The organelles of PMVEC infected by H9N2-SIV were decreased sharply, and vacuolization in mitochondria and apoptosis were also observed under electron microscope. The value of TEER was decreased significantly and the percentage of HRP influx was increased dramatically with the H9N2-SIV infection (P<0.01). The expression of TRPM2 at mRNA and protein levels in H9N2-SIV-infected PMVEC was increased dramatically at 24 h and 48 h as compared with control group (P<0.01). Annexin V/PI double staining showed that the cytomembrane was stained by great green fluorescence and some nuclei were stained by red fluorescence in H9N2-SIV-infected PMVEC. However, less fluorescence stained PMVEC were found in control group. CONCLUSION: The expression of TRPM2 at mRNA and protein levels is increased significantly, which is involved in cell damage and apoptosis induced by oxidative stress of H9N2-SIV infection.     

农业气象条件对温州蜜柑果实膨大的影响

根据怀化2010~2015年连续6 a无灌溉条件下温州蜜柑的气象、作物平行观测资料,分析了温州蜜柑果实逐旬膨大量与日照、气温、湿润指数的相关关系,率先改进和建立了蜜柑膨大旬气候生产潜力模型,分析了果实异常膨大的气象原因。结果发现:温州蜜柑多年逐旬平均膨大量呈抛物线变化趋势,和日照、气温、湿润指数为显著的类抛物线多项式关系,和气候潜力呈显著的指数关系。影响果实异常膨大的主要气象因素是干旱、暴雨等异常供水情况,其次为寡照及高温天气。     

不同处理方法对马缨杜鹃种子萌发和生长的影响

为探究马缨杜鹃种子萌发生长的最佳处理条件,应用不同方法处理种子.结果表明:马缨杜鹃种子用常温蒸馏水浸泡48 h萌发率最高,迟91.00%,发芽势达54.00%,是最佳处理方法;2.5%KNO3溶液处理,能促进种子萌发后胚根、胚芽的生长;70℃温水、硫酸、H2O2、CuSO4等处理种子萌发率低于50%,幼苗生长差.     

Characteristics of Dormancy of June-Bearing Strawberry(Fragaria Xananassa Duch. cv. Elsanta)

Abstract

The development of Fragaria xananassa Duch. cv. Elsanta was analyzed during summer and fall in order to define the sequence of growth alteration and dormancy with regard to inflorescence initiation. The leaf growth as well as the initiation of the inflorescence buds were followed in the fall by conditions imposed in a climate chamber, with plants then being transfered to conditions favorable for growth. Results pointed to clear changes in leaf growth characteristics over the late summer-early fall (September-October) period while the leaf emergence rate remained constant up to mid-October when it stopped. The first sign of inflorescence initiation started in early October, and the differentiation of the terminal flower reached the stamen initiation stage within 2 weeks. From early November, the terminal flower had initiated the carpel primordia and no further differentiation was detected later on. The plant growth potential, expressed by the size, at full growth, of the leaf or inflorescence axis emerging from the terminal bud, decreased progressively from early September and reached a minimum between October and November. By mid-December, the growth capacity of the plant was restored to a situation similar to that described for early September.     

Effect of glucagon-like peptide-1(7-36)NH2 on insulin secretion and membrane potentials of pancreatic islet β-cells

AIM: To observe pathomorphological changes in cerebral cortex and hippocampus in the mouse with synthetic vascular dementia. METHODS: The synthetic vascular dementia model was produced in the mouse. Animals were killed 7 d, 15 d, and 30 d after the operation, brain tissues were removed and embedded in paraffin. Section of 8μm thickness were stained with hematoxylin-eosin(HE) and Nissl methods, and observed with light microscope. RESULTS: The cerebral cortex in the mouse became thinner on the seventh day, karyopyknosis in partial nervous cells was formed, the number of local neurons was reduced, sieve structure was observed, and glial cells proliferated, with the similar results 15 d and 30 d after operation. Model mouses hippocampal cells in CA₁ area were reduced and almost disappeared 30 d after operation. At the same time, glial cells were abundantly proliferated, tubercles were formed. Cells in CA₂, CA₃ area were also reduced and hippocampal sclerosis occurred. CONCLUSION: Delayed necrosis of hippocampal pyramidal cells may be the pathological basis of ischemia cerebral vascular dementia.