培养基成分对沙打旺组培根生长及分泌物的影响研究

研究表明培养基成分可影响沙打旺组培根生长和根分泌物的产生。适宜沙打旺组培根生长的改良B5培养基组分为(以1L标准B5培养基为基础调节,下同)KNO32660.5mg、(NH4)2SO484.1mg、CaCl2.2H2O75.0mg、MgSO4.7H2O125.0mg、FeSO4.7H2O13.9mg、MnSO4.4H2O5.0mg和萘乙酸(NAA)0.6mg。组培根分泌物对沙打旺和小麦胚根生长抑制作用最强的培养基组分为KNO34565.9mg、(NH4)2SO448.1mg、MnSO4.4H2O5.0mg、肌醇150.0mg、烟酸1.5mg、盐酸吡哆辛1.5mg、盐酸硫胺15.0mg、NAA0.8mg和蔗糖50.0g。     

化感作用在设施黄瓜连作中的应用研究

简述了设施黄瓜栽培中化感作用的研究现状、化感物质的作用方式、途径、机理及其与设施生态系统环境的相互作用关系,概括了化感作用在黄瓜设施栽培中的意义并分析其发展前景。     

杉木经几种源植物水浸液处理后叶绿素、质膜透性及气孔的变化研究

用8种源植物及杉木枝叶不同浓度水浸液和清水浇灌盆栽杉木幼苗试验观测结果表明,经几种源植物水浸液处理后杉木叶绿素含量、叶片气孔孔径及其大小均比对照明显提高,叶片质膜透性则明显降低,但气孔频数无显著影响,其中木荷对提高叶绿素含量和降低质膜透性效果最佳,与杉木对照(CK_Ⅰ)和清水(CK_Ⅱ)处理相比,木荷1:6水浸液处理的杉木叶绿素含量分别提高49.3％和52.5％,而质膜透性分别下降30.6％和26.3％。檵木对提高杉木叶片气孔孔径及其大小效果最佳,与清水(CK_Ⅱ)处理相比分别提高27.1％和30.3％。水浸液浓度越大,其叶绿素含量、气孔孔径及其大小越大,则质膜透性越低。     

百合地上部分水浸液的化感效应研究

通过测定百合植株地上部分水浸液对5种植物种子发芽和幼苗生长的影响，初步研究了百合的化感效应。结果表明，百合地上部分的水浸液对几种受体植物种子的萌发、幼苗苗长和根长生长均有不同程度的抑制作用；随着水浸液浓度的增加，对萝卜种子发芽、根长生长和苗鲜重，以及对莴苣根长的抑制效应增加；随着水浸液浓度的降低，抑制作用逐渐减弱、消失，甚至转变为促进作用，表现在所有受体的苗长和番茄、大葱、黄瓜的根长上；百合水浸液对番茄种子发芽也表现出同样的浓度双重效应。     

Assessment of allelopathic potential of barnyard grass (Echinochloa crus-galli) on rice (Oryza sativa L.) cultivars

Laboratory, greenhouse and field studies were conducted to assess the allelopathic potential of 44 rice cultivars (Oryza sativa L.) on barnyard grass (Echinochloa crus-galli P. Beauv. var. oryzicola Ohwi). Rice cultivars exhibited marked differences in the inhibition of barnyard grass growth and development. In the laboratory, Gin shun rice cultivar extracts exhibited the greatest activity on the weed seedling growth, reducing dry weight by 61%, while Kasarwala mundara cultivar extracts exhibited the greatest activity on seed germination, reducing germination by 23% and germination speed by 46%. In a greenhouse study of a residue mixture, the Philippine 2 cultivar showed the greatest inhibition percentage on seedling emergence (57%), total seedling length (74%) and dry weight (73%). In the field study, the Juma 10 cultivar demonstrated the most inhibitory effect by reducing barnyard grass tiller number (80%), leaf area (49%) and leaf (61%) and stem (74%) dry weight (68%). These results suggest that there are differences among the varieties for allelopathic inhibition of barnyard grass, and that the development of barnyard grass suppressive rice cultivars that have greater allelopathic potential may be possible.     

Two potent allelopathic substances in cucumber plants

Since cucumber plants are mostly discarded as large waste after crop harvesting, allelopathy of cucumber plants was investigated for possible weed management options and utilization of the waste. Two potent growth inhibitory substances were isolated from an aqueous methanol extract of cucumber (Cucumis sativus L. cv. Phung Tuong) plants. These substances were determined as 9-hydroxy-4,7-megastigmadien-9-one (HMO) and (6S,7E,9S)-6,9,10-trihydroxy-4,7-megastigmadien-3-one (THMO) by the analysis of MS, ¹H NMR spectra and optical rotation. HMO inhibited the growth of cress (Lepidium sativum L.) and Echinochloa crus-galli (L.) Beauv seedlings at concentrations greater than 0.3 and 1 μM, respectively. THMO inhibited the growth of cress and E. crus-galli seedlings at concentrations greater than 1 and 3 μM, respectively. The concentrations required for 50% growth inhibition on roots and shoots of cress and E. crus-galli were 2.4–29.3 μM for HMO and 8.1–52.2 μM for THMO. The endogenous levels of HMO and THMO in cucumber plants were 31.8 and 43.5 μg g⁻¹ dry weight, respectively. These results suggest that HMO and THMO may be the causal factors for the growth inhibitory effect of cucumber plants. Therefore, cucumber plants may be potentially useful for weed management options in an agricultural setting, such as a cover crop and soil admixture, which should be investigated further in the field.     

西瓜化感作用及其化感物质成分分析

以早佳84-24为试材,研究了西瓜根、茎叶以及根系分泌物的化感效应,并对西瓜根、茎叶和根系分泌物中的化感物质进行了GC-MS检测。结果表明：西瓜根、茎叶水浸提液浓度为2.5 g?L-1时,促进西瓜种子发芽和幼苗生长|在浓度大于5.0 g?L-1时,表现为抑制作用,且随着浓度的增加,抑制作用增强|同一浓度时,西瓜茎叶水浸提液对西瓜种子发芽和幼苗生长的抑制作用大于根系水浸提液。西瓜根系分泌物浓度在2.5 μL?L-1时,促进西瓜种子发芽和幼苗生长|浓度为5.0 μL?L-1时,也开始表现为抑制作用。表明西瓜根、茎叶和根系分泌物对西瓜种子发芽和幼苗生长均呈现出低促高抑的规律。在西瓜根、茎叶和根系分泌物中共检测出32种化学物质,其中酯类化学物质最多,有14种|在西瓜根中检测到14种化学物质,茎叶中检测到19种,根系分泌物中检测到22种,其中一些曾被报道为化感物质,说明西瓜不同组织中化感物质的种类与含量不同,化感作用强度也不同。     

辣椒化感作用优势组分评价及GC-MS鉴定

应用隶属函数值法,分析评价了3种方法收集到的辣椒化感物质经3种不同洗脱剂的浓缩提取液对辣椒种子萌发的化感作用,确定了化感优势组分,并对优势组分进行了GC-MS鉴定。结果表明,连作6 a的辣椒种植地的土壤溶液经土壤原位收集法收集,并用甲醇洗脱所得的提取液（A2B3-6）为化感作用的优势组分,其化感隶属函数值为0.150。A2B3-6组分的GC-MS检测试验共检测到烷烃、芳香烃、醇、烯酸酯、芳香酸酯和含N化合物等多种物质,其中邻苯二甲酸二异丁酯的相对质量分数最大（47.67%）、匹配度（86%）较高,其可能对辣椒的连作障碍起着重要作用。     

秸秆还田的生化他感效应研究初报

盆栽试验结果表明 :蚕豆秸秆对小麦和大豆幼苗生长都有明显的他感相克作用 ,使其生物量分别减少 5 0 .4%和 5 8.2 % ;大豆秸秆对小麦幼苗生长有他感相克作用 ,而对大豆幼苗生长有自感相生作用 ,使其生物产量增加 1 9.8% ;玉米秸秆对小麦幼苗的相克作用最强 ,生物产量减产 60 .8% ,但对大豆幼苗生长的他感和玉米幼苗的自感相生作用显著 ,生物产量依次增加 1 8.7%和 1 0 .3% ;小麦秸秆对小麦、玉米和大豆幼苗生长都有相克作用 ,使其生物量分别减少 5 0 .8%、5 .1 %和 2 4.9%。秸秆对作物的他感效应 ,随着时间的推移而减弱。施用蚕豆秸秆 ,既能增大土壤养分贮量 ,又能提高土壤养分供应水平 ,玉米秸秆和小麦秸秆培肥土壤的作用居中 ,施用大豆秸秆虽能增大土壤养分贮量和供氮水平 ,但提高幅度不大。种植作物对秸秆培肥和供肥作用的发挥都有显著的促进作用     

麦冬水提液对莴苣等3种植物化感作用的初步研究

通过麦冬水提液对莴苣、黄瓜、萝卜3种不同植物的化感作用试验研究,结果表明:麦冬地下和地上部分水提液对供试种子黄瓜、萝卜的萌发表现显著的抑制作用,但对莴苣的抑制作用不明显;麦冬水提液对供试植物主根的生长产生抑制作用,而对黄瓜茎的生长表现促进作用。