苜蓿菌根对土壤中阿特拉津降解及酶活性影响

为进一步揭示丛枝菌根(AM)对土壤中阿特拉津的降解机理,建立了新型T型培养体系,并以阿特拉津敏感植物紫花苜蓿(Medicago sativa)接种摩西球囊霉(Glomus mosseae)形成的共生体系为研究对象,分别测定了苜蓿菌根对阿特拉津的降解效率及其根际土壤酶活性。当阿特拉津胁迫浓度为 20 mg/kg时,苜蓿菌根侵染率在25天时高达85.70%,阿特拉津降解率为70.22%,其中菌根贡献度为77.28%,表明苜蓿菌根对阿特拉津具有较强的降解能力。与此同时,添加阿特拉津能够提高菌根根际土壤中蔗糖酶、脲酶、过氧化氢酶和纤维素酶的活性。在接种G. mosseae和添加阿特拉津的双重作用下,4种土壤酶活性进一步增强。总之,本研究结果为应用AM真菌修复农药污染土壤提供了理论依据。     

海滨雀稗EST资源的SSR信息分析及EST-SSR标记开发

本研究探讨海滨雀稗EST序列中SSR位点的分布特征,开发EST-SSR引物分析其在草坪草种质资源遗传多样性研究中的应用。利用SSRIT软件对81220条海滨雀稗EST序列进行SSR位点搜索,分析EST-SSR的分布和特点,并利用Primer 3.0软件设计50对引物,选择10份草坪草对引物进行有效性和多态性检测。结果表明,从13705条海滨雀稗EST序列中检测到了22721个SSR位点,出现频率为16.87%。三核苷和单核苷酸重复为主要类型,所占比例分别为31.71%和29.28%。在检测到的163种基元中,出现最多的重复基元是A/T,其次是CCG/CGG和AGC/CTG。选择合成了50对EST-SSR引物,以海滨雀稗‘Adalady’基因组DNA为模板进行PCR扩增,其中37对引物能扩增出条带。利用这些引物对10份草坪草品种进行多态性检测,其中12对引物的扩增结果具有多态性。利用开发的EST-SSR标记对10份草坪草进行聚类分析,可将其分为4类。利用海滨雀稗EST序列开发SSR标记是可行的,开发的EST-SSR标记能有效用于草坪草遗传多样性研究。     

不同叶龄、秧盘及穴距对水稻产量和主要农艺性状的影响

以沈稻47为试验材料,研究不同叶龄、秧盘及穴距对水稻产量和主要农艺性状的影响。结果表明:叶龄和穴距相同条件下,最高分蘖数和有效穗数均为钵盘高于软盘,相同叶龄和秧盘条件下单位面积茎蘖数随穴距的增大而减少。4.1叶龄处理的产量显著高于5.7叶龄和2.5叶龄处理的产量。穴距20cm处理的产量最高,平均产量为11.84t/hm~2,显著高于穴距27cm处理,但与13cm穴距处理的产量差异不显著。钵盘育苗有效穗数较高,软盘育苗穗粒数、成粒率和千粒重均较高,从而更易获得高产。软盘育秧及钵盘育秧与4.1叶龄及穴距20cm的组合产量最高,分别为12.90和12.58t/hm~2。     

沟垄集雨技术研究进展及其在旱作马铃薯生产中的应用潜力

近年来,沟垄集雨技术正在逐渐成为我国旱区作物增产的重要措施。简要概述了沟垄集雨技术的概念,综合目前的研究进展,从集雨、保墒和用水三个环节总结了影响沟垄集雨技术效果的因素,分析了沟垄集雨栽培技术对作物生长发育的影响。最后,展望了沟垄集雨技术在旱作马铃薯生产中的应用潜力。     

浇筑式钢桥面铺装层推挤变形病害机理分析

以贵州省北盘江大桥钢桥面铺装层推挤变形病害为研究背景,采用凝胶渗透色谱法(GPC)和傅里叶变换红外光谱法(FTIR),从沥青分子尺度分析钢桥面铺装产生推挤变形的原因。分析结果表明:沥青老化并不是造成钢桥面铺装层推挤变形的主要原因;从现场调查可知,第2层粘层粘结能力的降低是造成钢桥面铺装层推挤变形病害的次要原因;通过级配分析发现,造成钢桥面铺装层推挤变形的主要原因是浇筑式沥青混合料(GA)级配偏细以及GA中集料颗粒的棱角性较差所致。     

有机栽培水肥一体化系统设计与试验

A water and fertilizer integrated system for organic cultivation was designed. The system integrated functions of preparing and compounding organic liquid as well as automatical irrigation. Through different subroutines of the system, the aerobic fermentation of organic materials, liquid filtration, compounding and dilution of stock solution, and decision and execution of irrigation strategy can be conducted. Thus, the integration of preparation and management of nutrient solution in organic cultivation, as well as high efficiency and fine management in water and fertilizer could be achieved. In order to verify the reliability and applicability of the system, coconut chaff was selected as organic matrix and non soil and organic cultivation experiment of cucumber was carried out in the solar greenhouse. The results showed that the system was operated stably in preparation of organic liquid and management of water and fertilizer was good in cucumber cultivation. The mechanization and automation of organic fertilizer and water management was implemented. The yield of cucumber was up to 48165kg/hm2, the content of total soluble sugar, vitamin C and titratable acidity were 2.7%, 99.2mg/kg and 008%, respectively. The development and application of this system would break through the bottleneck that existed in water and fertilizer management in organic cultivation, and it had important realistic significances.     

Effects of water and nitrogen addition on vegetation carbon pools in a semi-arid temperate steppe

Global change will lead to increases in regional precipitation and nitrogen(N) deposition in the semi-arid grasslands of northern China. We investigated the responses of vegetation carbon(C) pools to simulated precipitation and N deposition increases through field experiments in a typical steppe in Inner Mongolia. The treatments included NH_4NO_3 addition at concentrations of 0(CK), 5(LN, low nitrogen), 10(middle nitrogen, MN), and 20(HN,high nitrogen)(g m~(-2)a~(-1)) with and without water. After three consecutive years of treatment, from 2010 to 2012,water addition did not significantly change the size of the total vegetation C pools, but it significantly decreased the ratio of root:shoot(R:S)(P = 0.05) relative to controls. By contrast, N addition significantly increased the total vegetation C pools. The C pools in the LN, MN and HN treatments increased by 22, 39 and 44 %, respectively. MN produced the largest effect among the N concentrations,although differences between N-added treatments were not significant(P [ 0.05). N addition significantly reduced the ratio of root:shoot(R:S)(P = 0.03). However, there were no significant interactive effects of water and N addition on the vegetation C pools.     

Property Rights Effects on Farmers’ Management Investment in Forestry Projects: The Case of Camellia in Jiangxi,China

China’s central government has carried out a series of collectivization and de-collectivization attempts of forest tenure over time, which have led to multiple forest tenure arrangements within provinces. This paper investigates the motivation of farmers to maintain forestry under various forest tenure regimes. First, the paper provides a qualitative analysis of the different forest tenure regimes using the New Property Rights Theory. Second, an econometric analysis based on data from camellia projects in Jiangxi province is carried out. Camellia projects are long-term projects for the production of non-timber forest products which are important for rural income generation. Qualitative results of the research show that a multitude of different tenure regimes exist across forestry projects. Community-based or collective forest management regimes are the most important tenure regimes in forest management in Jiangxi province. Village communities and farmers are the main actors in forest resource management and investment in camellia projects in Jiangxi province. The results of the econometric analysis show that higher degrees of tenure security and residual claimancy for farm households lead to a higher use of household labor and capital within camellia forestry projects. Uncertainty about the future forestland distribution is an obstacle for household investments in forestry.     

种间关系对中条山油松人工林天然更新及群落稳定性的影响

[目的]为了揭示种间关系对中条山油松人工林天然更新及群落稳定性的影响,为油松人工林经营管理提供理论依据.[方法]基于中条山油松人工林群落样地调查数据,分析油松人工林下主要植物的种间关联性、生态位重叠及群落稳定性,并在此基础上探讨种间关联和生态位理论在油松人工林天然更新障碍及群落稳定性形成机制中的作用.[结果]中条山油松...