一个水稻三倍体×二倍体杂交F2群体的微卫星杂合性丧失     

谢兆辉 《安徽农业科学》2007,35(11):3163-3164,3166

DB102为一田间发现的三倍体水稻,利用它做母本与二倍体水稻中作59杂交,得到一个早世代(F2)稳定群体,通过微卫星分析发现,该群体中有一些微卫星位点发生了杂合性丧失,且至少6条染色体上发生微卫星位点杂合性丧失(loss of heterzygoisity LOH)可能有DNA序列变化。而微卫星位点的杂合性丧失又可能与该杂交组合早世代稳定有关。  相似文献   

农田氮磷流失与农业非点源污染及其防治   总被引：9，自引：2，他引：9  

彭畅  朱平  牛红红  李强  张玉龙 《土壤通报》2010,(2)

农田氮、磷的流失,不仅造成化肥利用率的降低,还会引起农业非点源污染。通过分析国内外由于农田氮磷流失而引起的农业非点源污染现状和流失途径,提出加强污染源监控预警,综合运用管理措施和生态工程等,控制和减少农田氮磷流失对水体环境的污染。  相似文献   

1976-2015年中国主要农业气象灾害的变化特征   总被引：1，自引：0，他引：1  

刘笑  何学敏  游松财 《中国农业气象》2017,(8):481-487

根据1976-2015年受灾、成灾和绝收面积等统计数据,计算中国主要农业气象灾害包括洪涝、干旱、风雹和低温灾害的受灾率、成灾率、绝收率和损失率,并对其变化趋势、灾害损失和灾害等级的变化特征进行分析.结果表明:(1)总体上,1976-2015年中国主要农业气象灾害的受灾率呈显著减小的趋势,而成灾率和绝收率变化趋势则不显著.干旱与农业气象灾害总体变化趋势相一致;洪涝受灾率、成灾率和绝收率存在阶段性的变化特征,1986-2005年各项均值最大;风雹灾害下降趋势显著,受灾率、成灾率均显著减小;而低温灾害各项指标的年代均值逐渐增加.(2)研究期内四大灾害总体损失率的上下限呈先增加后减小的趋势,平均灾害损失率为7.1％～15.7％.洪涝和干旱灾害损失率的上下限变化趋势与农业气象灾害总体一致,其平均损失率分别为2.0％～4.2％、3.8％～8.6％;而风雹灾害损失率的上下限呈减小的趋势,平均损失率为0.8％～1.7％;低温灾害损失率的上下限呈增加趋势,平均损失率为0.5％～1.1％.(3)研究期间洪涝重灾发生次数最多,为突发性灾害;干旱、风雹中灾和重灾发生次数之和最多,为常态性灾害.  相似文献   

不同下垫面条件下土壤养分流失研究概况   总被引：1，自引：0，他引：1  

赵旭珍  李纯乾 《中国农学通报》2016,32(21):129-133

中国的土壤侵蚀十分严重,而随着土壤侵蚀的发生发展将导致土壤养分流失、土壤贫瘠、土地生产力降低等多种问题。影响土壤侵蚀和土壤养分流失的主要因素包括降雨、下垫面条件和人为因素。通过总结多年来对不同下垫面条件下土壤养分流失情况的研究结果,分析下垫面条件中地表植被、坡度、坡长、土壤含水量、土壤颗粒等因素对土壤养分流失的影响,总结目前正在试验或用于实践的各种用于控制或者减少土壤养分流失状况的措施,以期对下一步的研究工作提供参考。  相似文献   

沂蒙山区典型小流域次暴雨的氮磷输出特征     

李振炜  吴迪  于兴修  井光花 《安徽农业科学》2012,(12):7269-7270,7312

[目的]揭示暴雨条件下沂蒙山区的氮磷流失特征。[方法]以沂蒙山区沂河上游的孟良崮小流域为例,对2010年8月12日一场暴雨的径流及氮磷流失动态过程进行了监测分析。[结果]暴雨条件下产流迅速,降雨强度峰值出现于流量峰值之前;铵态氮(AN)和总氮(TN)浓度先变大后趋于稳定,硝态氮(NN)降雨初期无明显变化,后期逐渐变大并趋于稳定;水溶性无机磷(DOP)浓度呈锯齿状变化,水溶性有机磷(DIP)、水溶性全磷(DP)、颗粒态全磷(PP)和全磷(TP)浓度先变大后趋于稳定,浓度峰值出现于流量峰值之前;TN和TP输出浓度较大,远超过水体富营养化的标准。[结论]该研究可为沂蒙山区农业非点源污染的合理治理提供科学依据。  相似文献   

中性纤维素酶整理牛仔布的工艺优化   总被引：1，自引：0，他引：1  

蔡金涛  焦聪  崔琰  杨佳颖  陈红漫  阚国仕 《辽宁农业科学》2011,(3):12-15

根据芽孢杆菌M01-ZL-110所产纤维素酶的酶系组成及酶学性质特点,将该菌株发酵所产纤维素酶酶液应用于牛仔布的整理工艺。以减量率为试验评价指标,通过正交试验对加酶量、温度、整理时间及pH值等参数进行优化。试验结果表明由芽孢杆菌M01-ZL-110制备的中性纤维素酶对牛仔布酶洗整理的最佳条件为：30 m l的溶液体系中酶液加入量为20 m l,pH为6,温度为60℃,整理时间是60 m in,并且对牛仔布表面进行了酶洗前后扫描电镜观察比较。  相似文献   

论鄂尔多斯东北部的资源开发与环境整治   总被引：3，自引：0，他引：3  

郭绍礼 《干旱区资源与环境》1994,8(1):29-43

本文是从资源开发条件的评价入手，揭示所出现的环境问题，并提出建立人工高效开发－整治型的综合模式结构，以便持续稳定地协调好资源开发与环境整治的关系，促进这里的经济发展。  相似文献   

Relationship between genetic instability of nm23H1 gene and clinical pathological characteristic in hepatocellular carcinoma     

LU Hai-ying  LI Ji-cheng  LIANG Xiao-yue  ZHANG Ling 《园艺学报》2007,23(9):1732-1736

AIM: The aim of this study was to examine the microstatellite instability (MSI) and loss of heterozygosity(LOH) of locus D17S396 on chromosome 17 and their influence on the expression of nm23H1 in hepatocellular carcinoma (HCC),which may provide experimental evidence for the mechanism of nm23H1 gene and tumor metastasis.METHODS: Techniques such as DNA extraction from formalin-fixed paraffin-embedded tissues,PCR-SSCP,ordinary silver stain were used to study MSI and LOH of locus D17S396.Envision immunohistochemistry and Leica-Qwin computer imaging techniques were used to assess the expression of nm23H1.RESULTS: ① The frequency of heredity instability of HCCs was 35.42%.The frequency of LOH in the cases with lymph node or distant organs metastasis or not and with intrahepatic metastasis or embolus of portal vein or not was significantly different (P<0.01),it was higher in stage TNM Ⅲ than that in stageⅠ and Ⅱ.Moreover,it was higher in high tendency to invasion or metastasis cases than that in the low tendency cases (P<0.01).② The expression of nm23H1 was 56.25%.It was significantly different in Edmondson grade,TNM stage and in lymph node or distant organ metastasis cases (P<0.01).The cases with high tendency of invasion or metastasis exhibited lower nm23H1 expression compared with low tendency cases (P<0.01).③ The positive rate of nm23H1 protein in LOH positive group was lower than that in LOH negative group (P<0.05).CONCLUSION: The results indicate that both MSI and LOH of nm23H1 gene control the development of HCC independently in different pathways.LOH inhibits the expression of nm23H1,which endows it with high aggressive and poor prognosis.Increase in the amount of nm23H1 protein expression effectively restrains the tendency to invasion or metastasis of HCCs and improves prognosis of patients.  相似文献   

Rust control and EBDC residues in green beans sprayed with mancozeb and sulphur     

D. A. Fontem  H. Bouda 《国际虫害防治杂志》2013,59(4):211-214

Rust control and ethylenebisdithiocarbamate (EBDC) residues in green beans ( Phaseolus vulgaris L. 'Morgan') were evaluated in two seasons of 1993 in Dschang, Cameroon. Four weekly applications of mancozeb (2.8 kg ha- 1), sulphur (2.24 kg ha- 1), or mancozeb+sulphur (1.4+1.12 kg ha- 1) were initiated from initial rust symptoms. In both seasons, treatments with mancozeb alone resulted in a low area under pustule count progress curve (AUPPC) and a significant increase in leaf area index, and pod and green fodder yields. Pod yields were negatively correlated with AUPPC. Pod yield loss was estimated at 61% and 32% in the early and late seasons, respectively, while losses in green fodder yields were 57% and 24% respectively. EBDC residue levels decreased significantly with a delay in pod harvestand when pods were washed in running tap water. Residue levels were high in the late season, possibly due to low rainfall. Pods exposed to the combined fungicidal treatments accumulated higher levels of residues than those sprayed with mancozeb alone, suggesting a potential risk of EBDC accumulation on pods when EBDCs are mixed with sulphur.  相似文献   

森林火灾损失评估方法体系研究综述     

杨光  舒立福  邸雪颖  蔡慧颖 《安徽农业科学》2014,(31):10961-10964

通过借鉴国外森林火灾损失评估方法和评估系统,重点剖析了现阶段我国森林火灾损失评估工作中存在的问题,并针对制定适用于我国的森林火灾损失评估体系,探讨了构建我国森林火灾损失评估体系关键技术问题,提出了未来森林火灾损失评估研究需加强的研究方向。  相似文献