Irrigation Water Management for Efficient Water Use in Mulched Onion

Caused by the necessarily imperfect seed placement accuracy of sowing machines and, additionally, caused by many other biotic and abiotic factors, the resulting plant stands exhibit nonregular spatial distributions of its plants. Based on several simplifying assumptions, a stochastic approach is developed which allows an estimation of the effects of nonregular spatial patterns on yield per area. In this approach, two random variables are attached to each plant: single plant yield E and individual space A . The latter is estimated by the area of Thiessen polygons. Yield per area, calculated by the expectation of the ratio E/A , can be approximately expressed dependent on the means ( Ē and Ā ) and coefficients of variation ( v _E and v _A ) of E and A and their correlation ( r _EA ). In relation to the commonly used estimate Ē/Ā for yield per area, one obtains yield decreases if v _A / v _E  <  r _EA . This inequality, however, will be usually valid in the field of applications. The theoretical approaches and results were applied to three experimental data sets for drilled seeds of winter oilseed rape ( Brassica napus L.) (plant density: 60 plants m⁻², row distance: 10 cm). These data sets are characterized by different accuracies of longitudinal distributions within rows (58 %, 101 %, 150 %): yield depression increases with an increasing variability of plant distances within rows.     

柚矮化病的品种感病性调查

以特征性症状春梢叶片扭曲畸形和枝条茎陷点为诊断依据，调查结果表明，５５个柚类品种中有２２个发病，占调查品种数的４０％；２８个沙田柚砧穗组合中有２２个发病，占调查砧穗组合数的７８．５％。以沙田柚实生苗和酸柚实生苗作指示植物，对温州蜜柑上的类似矮化病的叶片扭曲症状进行鉴定的结果，指示植物上表现出与接种沙田柚矮化病病原的指示植物相似的春梢叶片扭曲及茎陷点症状。     

浅谈药用植物在现代园林中的独特应用

通过对药用植物的独特性能及其代表植物的介绍,提出了其独特的园林应用优势,并就其在园林绿化景观中的应用形式和配置方法进行阐述。     

高等植物小孢子胚胎发生的细胞和分子生化机制研究进展

小孢子胚胎发生的细胞学研究已取得了显著进展,并分离鉴定出一些小孢子胚胎发生表达的胚胎专一基因,但小孢子胚胎发生的机理尚未完全明确。综述了高等植物小孢子胚胎发生的细胞学以及分子和生物化学方面的最新研究进展,旨为进一步揭示小孢子的胚胎发生机理提供十分有用的信息。     

兰州市立交桥桥体绿化试验

针对兰州市立交桥施工设计未包括桥体绿化工程的现状和桥体绿化各部位的环境条件,选择出了合适的植物栽培品种和合理的配植形式,总结了施工过程中的经验教训和当年能收到较好的绿化效果的土壤处理、牵引、理藤、修剪等施工养护管理技术。     

沉水植物在水环境治理中的应用研究

淡水是人类生存不可或缺的珍贵资源，然而随着近年工业快速发展及人口大幅增加，水环境污染问题日益突出，进一步加剧了水资源短缺的矛盾。沉水植物因其各部分均可吸收养料且通气组织特别发达，常被用作水环境治理的先锋种，其具有去除氮磷、提高透明度、固定底泥、抑制蓝藻、微生物协同等重要作用。本文就沉水植物及其设计原则、作用原理展开阐述，并分析应用中存在的问题，展望未来研究方向，以期为沉水植物今后的应用与研究提供参考。     

无机盐、蔗糖、活性炭对阴生观叶花木试管苗生根的影响

对影响珍稀阴生观叶花木试管苗生根的几个因子－无机盐、蔗糖、活性炭的浓度进行了试验。结果表明：随着矿物元素、蔗糖与活性炭浓度的增加，试管苗生根率也增加，但当其浓度增加到一定数值后，生根率则开始呈下降趋势，生根阶段，所需大量元素与蔗糖的量较低，但应增加矢量的活性炭，三者最适浓度分别为１／２ＭＳ，２０ｇ／Ｌ，２ｇ／Ｌ。     

Over-expression of the citrus gene CtNH1 confers resistance to bacterial canker disease

Citrus canker is a devastating disease, caused by Xanthomonas axonopodis pv. citri (Xac). It is well established that the NPR1 gene plays a pivotal role in systemic acquired resistance (SAR) in Arabidopsis. In this study, we report the isolation and characterization of an NPR1 homolog from citrus, namely Citrus NPR1 homolog 1 (CtNH1). Sequence alignment and phylogenetic analysis indicate that CtNH1 is closely-related to the Arabidopsis NPR1 gene and its orthologs from rice, grapevine, and cacao. When over-expressed in citrus, CtNH1 confers resistance to Xac and leads to constitutive expression of the pathogenesis-related (PR) gene chitinase 1 (Chi1), suggesting that CtNH1 is orthologous to NPR1.     

对朗乡林业局野生经济植物的调查

分析论述了朗乡林区野生经济植物的种类、蕴藏数量以及开发保护利用意见。     

石柱县莼菜大田植物多样性调查与分析

调查重庆市石柱县野生莼菜大田的植物多样性。共发现植物244种,隶属于74科200属。其中菊科26属30种,禾本科19属21种,荨麻科8属12种,唇形科10属11种；外来入侵植物有34科63属69种,菊科、禾本科物种数最多；本土危害物种9科10属12种,危害能力极强。此外,还发现国家二级保护植物金荞麦(Fagopyrum dibotrys),重庆市省级重点保护野生植物瓶尔小草(Ophioglossum vulgatum)。区系分析、植被类型、植物组成分析显示,该地植物区系丰富,属于热带和温带气候带之间,且物种多样性相对丰富,湿地植物数量相对较高,危害植物干扰严重。