基于茎直径微变化的梨枣灌溉指标的初步研究  

Rational Indicators for Irrigation Scheduling of Pear-jujube Based on Microchanges of Stem Diameter

作　　者：韩立新[1,2] 汪有科[1,3] 李晓彬[1,2] 

机构地区：[1]国科学院水利部水土保持研究所,陕西杨凌712100 [2]中国科学院研究生院,北京100049 [3]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《园艺学报》2012年第3期552-560,共9页Acta Horticulturae Sinica

基　　金：国家科技支撑计划项目(2011BAD29B04);陕西省科技统筹创新工程项目(2011KTCL02-02)

摘　　要：研究了4年生酸枣砧梨枣(Ziziphus jujuba Mill.)植株主干茎直径微变化指标对土壤水势(SWP)变化的响应规律,以及与气象要素的关系。结果表明:土壤水势降低引起茎直径日最大收缩量(MDS)增大,日生长量(DG)、生长速率(TGR)和日最大值(MXTD)降低。在水分亏缺发展阶段和水分亏缺维持阶段,MDS和TGR的噪声信号(变异系数)较小,信号强度与噪声信号的比值较大,表明其对土壤水势变化反映敏感。此外,MDS、TGR与潜在蒸散量(ET0)、正午水汽压亏缺(VPDmd)等气象因子的相关性显著,均能反映大气的干旱程度,因此TGR和MDS可作为梨枣水分亏缺的诊断指标。Banana fusarium wilt was caused by Fusarium oxysporum f. sp. cubense race 4（Foc 4）. The changes of pathogenic activity of Foc 4 crude toxin after the treatments of autoclave,different pH values,ultraviolet irradiation and methanol precipitation were determined so as to understand the basic physicochemical properties of the toxin. The results showed that the toxin had a strong thermal stability, and still had a strong pathogenic activity after autoclave for 20 min;The pathogenic activity of the toxin would be reduced under both acidic（pH 3–6）and alkaline（pH 8–10）conditions;The supernatant rather than precipitation had the pathogenic activity after methanol precipitation treatment;The ultraviolet radiation could reduce the toxicity of the toxin. The above mentioned findings suggested that the toxin belongs to a small molecule,non-protein compound with higher polarity. Furthermore,effects of the toxin on seed germination and plantule growth of different plant species were determined so as to understand the host specificity of the toxin,and the results indicated that the toxin had different inhibitions on the seed germination and plantule growth of different plant species,indicating that the toxin was a non-host specific toxin.

关 键 词：梨枣 茎直径微变化 土壤水势 信号强度 水分亏缺 

分 类 号：S665.1[农业科学—果树学]