核桃坚果水浸液对4种植物种子萌发及生长的影响

为探究核桃果实不同部位水浸液对植物种子萌发及生长的影响,本试验以莴笋、萝卜、马蹄金、野牛草4种种子为试材,对其进行核桃种子、种仁及种皮的水浸液浸泡处理,进而研究核桃果实不同部位水浸液的化感作用,旨在探讨核桃水浸液对4种植物种子萌发及生长的影响。结果表明,在特定浓度下,核桃种子的水浸液对莴笋、萝卜、马蹄金、野牛草种子萌发均起到抑制作用,对萝卜幼苗生长的抑制作用大于莴笋幼苗的生长,对马蹄金和野牛草种子生长的抑制作用大于莴笋和萝卜。核桃种仁的水浸液对幼苗生长的抑制作用大于其余2个部位的影响,表现为:核桃种仁大于核桃种壳和核桃种子。本研究探索了核桃种子水浸液的化感作用及抑制植物种子萌发的物质,为农作物间作套种、化感抗害提供了依据和指导。     

油菜根系分泌物的GC-MS检测方法研究

为筛选建立BP-5MS毛细管柱检测油菜根系分泌物的方法,本文采用水培试验,利用CH2Cl2提取油菜幼苗的根系分泌物,通过GC-MS检测分离鉴定。结果表明,根据待测物质组分性质,采用合适的溶剂延迟,分阶段细化升温程序,检测出来的特征峰较多且分布密集,特征峰分离相对比较好。从检测结果看,油菜苗期根系分泌物主要包括烃类、醇类、酯类和酸类化合物,且烃类和醇类化合物的相对含量较高,这些物质大多数具有化感作用,对植物在逆境环境中的生长和发育有一定的影响。     

不同化感型杉木无性系根际土壤微生物数量季节动态

以杉木化感忍耐型和化感敏感型无性系为材料,杉木1代林、连栽2代林、连栽3代林以及阔叶林土壤为培养基质,采用盆栽方式,测定不同化感型杉木无性系根际土壤细菌、真菌和放线菌数量的季节动态。研究表明,相同培养基质及测试时间下,杉木忍耐型无性系根际土壤微生物总数及细菌、放线菌和真菌数量均高于敏感型无性系,且随着培养时间延长,增加幅度逐渐变大。同一培养基质下,不同化感型杉木无性系根际土壤微生物总数及细菌数量表现为2011年9月最高,2011年12月最低;真菌及放线菌则表现为2011年6月最高,2011年12月最低。相同测试时间下,随着连栽代数的增加,不同化感型杉木无性系根际土壤微生物总数及细菌、真菌和放线菌数量均呈逐渐下降趋势。     

Differences in ecological and allelopathic traits among Alternanthera philoxeroides populations

Based on a field investigation and laboratory trials, this study compared the invasive ecology of aquatic and terrestrial alligator weed (Alternanthera philoxeroides G.) ecotypes. The aquatic ecotype showed a stronger eco‐adaptation than the terrestrial ecotype. Alligator weed performed well in wetland and riparian habitats, where it was so competitive that only one‐to‐three other plant types grew successfully in its company. In contrast, it exhibited poor growth in upland fields and parks, where the terrestrial ecotype was dominated by 6–11 other alien plant species. The aquatic ecotype exhibited significantly greater growth inhibition of Microcystis aeruginosa. The ecotypes differed in their pattern of allelopathic inhibition of water blooms. The allelopathic effect of the aquatic ecotype persisted for a period exceeding 20 days, whereas the terrestrial ecotype's allelopathic effect subsided in <5 days. The aquatic ecotype had higher levels of antioxidant compounds, including soluble protein and flavones, and the activity of protective enzymes was also higher, which included superoxidase dismutase, peroxidase and catalase. Alligator weed's unique characteristics derive mainly from its strong allelopathic potential and tolerance of eutrophication in aquatic habitats.     

薇甘菊对鬼针草种子萌发和幼苗生长的化感影响

测定了薇甘菊提取液对鬼针草种子萌发和幼苗生长的化感影响。结果表明,薇甘菊提取液处理,非入侵地鬼针草种子萌发率为52%,入侵地鬼针草种子萌发率为60%,薇甘菊对非入侵地鬼针草种子萌发的化感影响大于对入侵地鬼针草种子萌发的化感影响;薇甘菊对鬼针草幼苗总叶面积、最大量子产额和冠重没有明显的抑制作用;非入侵地处理与对照鬼针草幼苗的根重分别为23.50 g和36.92 g,入侵地处理与对照鬼针草幼苗的根重分别为22.19 g和16.53 g,薇甘菊对非入侵地鬼针草幼苗的根重的影响大于对入侵地的;入侵地鬼针草种子及幼苗对薇甘菊具有一定的化感抗性。     

Screening of 170 Peruvian plant species for allelopathic activity by using the Sandwich Method

Peru is one of the 20 botanically extremely diverse countries in the world, with >17 000 flowering plants, of which 30% are endemic. So far, no systematic research has been conducted on the screening of the allelopathic plants. In this study, the allelopathic activity of 170 species from 61 families of Peruvian plants that were collected from the three main regions of Peru – the Costa (Pacific coastline), the Sierra (Andean mountains), and the Selva (Amazonian rainforest) – was evaluated. The allelopathic activity was determined by the Sandwich Method, which can evaluate the activity of leaf leachates. The species that were found to be highly inhibitory in this screening, under the criterion of >90% inhibition of the radicle of lettuce (Lactuca sativa) seedlings, were Aristeguietia ballii and Diplostephium foliosissimum (Asteraceae) and Spondias mombin (Anacardiaceae). All of these species are native plants from Peru. This study gives a strong clue regarding the potential of isolating potent allelochemicals from these plants in the future.     

老参地土壤提取液对水稻种子萌发及幼苗生长的化感效应

【目的】探讨不同质量浓度老参地土壤提取液对水稻种子萌发、幼苗生长及光合作用的影响,为人参水稻轮作体系研究提供参考。【方法】采用室内生物测定法及基质盆栽试验,以去离子水为对照（CK）,研究低（10 g/mL）、中（20 g/mL）和高（40 g/mL）3种质量浓度的老参地土壤水提液,对水稻种子萌发、幼苗生物量、根系活力、叶片可溶性蛋白和叶绿素合成、电导率及净光合速率的影响。【结果】与对照相比,不同质量浓度老参地土壤提取液处理后水稻种子萌发率、苗高及幼苗生物量均有不同程度的增加,其中随着老参地土壤提取液处理质量浓度的升高,水稻种子萌发率逐渐增加,中、高质量浓度处理与CK差异显著（P<0.05）。当老参地土壤提取液质量浓度为40 g/mL时,单株鲜、干质量最大,分别为14.22和1.66 mg。各质量浓度老参地土壤提取液处理对苗高影响不显著,却明显抑制了水稻幼根的生长。中、高质量浓度老参地土壤提取液处理均显著促进了幼苗叶片可溶性蛋白合成,低质量浓度老参地土壤提取液处理明显促进了根系活力的增加,而高质量浓度老参地土壤提取液处理则降低了根系活力;不同质量浓度老参地土壤提取液处理均显著降低了水稻叶片的叶绿素含量和绝对电导率;低、中质量浓度老参地土壤提取液处理下叶片净光合速率均有增加,而高质量浓度老参地土壤提取液处理则表现出微弱的抑制作用。【结论】老参地土壤水提取液对水稻早期萌发生长有一定的促进作用,且对部分生理指标（根系活力和净光合速率）表现为“低促高抑”的剂量相关性反应。     

林下枯落物浸提液对香果树种子萌发及幼苗生长影响的化感效应

研究了香果树的落叶、树枝、果皮及竹叶等4种林下枯落物浸提液对香果树种子萌发和幼苗生长的化感效应。结果表明:香果树落叶、树枝及竹叶浸提液对香果树种子萌发具有不同程度抑制作用,并随浓度升高抑制作用增强。对香果树幼苗生长的化感效应,香果树落叶和果皮浸提液具有显著抑制作用,随浓度升高抑制作用增强;香果树树枝浸提液总体趋势具有“低促高抑”的双浓度效应;竹叶浸提液对香果树幼苗不同部位化感效应不同,具有“促茎抑叶”的化感效应。     

青蒿素对植物化感效应研究进展

青蒿素是一种由部分蒿属植物产生的倍半萜内酯,是一种有效的抗疟疾药物,对癌症、肝炎和血吸虫病等均有疗效。植物化感作用是植物(含微生物)通过释放化学物质到环境中对其它植物产生的直接或间接的有害作用。综述了青蒿素的合成、影响青蒿素化感效应的因素及释放途径、青蒿素对土壤成分及植物生长的影响等方面的研究成果,并指出了进一步的研究方向。