环境对茶树产生化感物质的影响

研究了不同生态环境、生长季节、肥培管理等因子对茶树产生化感物质的影响.结果表明,茶园土壤中积累的化感物质对茶苗的生长产生抑制作用;茶树化感物质的产生受植物本身所处的生态环境条件的影响,季节变化、光照、温度是影响茶树产生化感物质的主要环境因子.     

假臭草水浸提液化感作用研究

以小白菜(Brassica campestris L.ssp.Pekinensis(Lour.)Olsson),萝卜(Raphanus sativus L.),水稻(Oryzasativa L.),热研2号柱花草(Stylosanthes guianensis cv.Reyan No.2)作为测试植物,研究新鲜假臭草(Praxelisclematidea(Griseb.)King and Robinson)水浸提液对种子发芽,新鲜假臭草和风干假臭草水浸提液对幼苗早期生长的化感效应以及不同生长环境下的假臭草浸提液对萝卜幼苗早期生长的化感作用。结果表明:新鲜假臭草浸提液对4种测试植物的种子发芽都有抑制作用。假臭草叶和完整植株水浸提液的化感作用明显大于其它器官水浸提液化感作用,叶可能是假臭草释放化感物质的主要器官。风干和新鲜假臭草水浸提液在低浓度时抑制所有测试植物幼苗根系生长。在逆境(如干旱和养分胁迫)中,假臭草会释放更多的化感物质,从而导致其化感作用增强。     

杂草化感作用与信息互作

为了解和掌握杂草化感作用的研究进展、明确今后的研究重点,本文综述了蕨类、豆科和菊科杂草的化感作用研究现状。目前已鉴定出的化感物质主要是有机酸类、生物碱类、萜类、糖苷类、烯类和黄酮类等,这些化感物质对多种受体植物表现出不同程度的抑制或促进作用。其化感作用机理表现在各种酶活性降低、导致原生质体膜、细胞膜和叶绿体膜的破坏、对光合作用的影响、对某些激素含量水平的影响、营养元素的吸收及水分的平衡等几个方面。提出今后应加强研究杂草与作物的相互作用,杂草种、属间的化感作用与信息互作,保育生物多样性丰富、田园风光优美、动植物安全的生态系统。     

化感物质对植物生长的影响及其在茶叶生产中的应用

化感物质通过化感作用对植物的生长发育起抑制或促进作用，诱导植物产生直接抗性或间接抗性，从而对植物的生长造成影响。这种作用在茶叶生产中具有重要的现实意义和广阔的应用前景。     

薇甘菊的分布危害、生物防治及资源化利用研究现状与展望

薇甘菊作为唯一一种全国林业检疫有害植物，由于其较强的攀援、繁殖扩散能力，以及极强的化感作用，对入侵地区的林农业发展产生了极大的危害；作为一种菊科植物薇甘菊有极强的资源化利用价值，在生物农药，药物等方面都有着广泛的利用前景。此文对薇甘菊的生物学特性、分布、适生区及危害进行介绍，对国内外薇甘菊生物防治及资源化利用的研究现状进行综述。     

红树植物化感作用对中肋骨条藻生长的影响

到目前为此,尚未见红树林区发生赤潮的报道:红树林不发生或极少发生赤潮的原因尚未完全清楚.红树林对污水具有净化功能,同时对其它植物存在化感作用.比较了几种红树植物粉对中肋骨条藻生长的效应,研究了红树粉及其水浸液、红树根系分泌物(无土栽培营养液)对中肋骨条藻生长的影响.结果表明:红树粉、红树粉水浸液、红树根系分泌物对中肋骨条藻生长均有明显的抑制作用:红树植物对中肋骨条藻生长存在化感作用,化感作用的强弱与红树总酚的含量不成正比,可能存在其它化感物质同时起作用.提示某些红树植物中存在抑藻物质,并能分泌到植物体外(主要通过根分泌),抑制赤潮藻类大量繁殖,对赤潮有一定的防治作用.     

植物间的他感作用及其应用

植物间的他感作用(Allelopathy)是指植物在其生长发育过程中,通过排出体外代谢产物及腐烂植株物质,改变其周围微生态环境,从而导致同一生态环境中植物与植物,植物与微生物之间相互排斥或促进的一种自然现象。此现象早在公元前370年就被发现,但此概念是由莫利什(Molisch)于1937年首次提出,随后德国的G.Grumme~r(1954)和美国的E.L.Rice(1974)先后发表了题为《他感作用》专著。他们揭示了自然界中高等植物之间普遍地存在着他感作用。近年来,该领域的研究进展迅速,成果丰硕。现根据收集的资料并结合笔者浅见对他感作用的作用物种类、释放方式、作用方式以及在生产实践中的应用作一概述。     

刚果12号桉叶片水抽提物对4种植物幼苗生长的影响

采用盆栽法研究了刚果12号桉叶片水抽提物在水分胁迫（水渍与干旱）和养分缺乏与丰足的环境条件下对4种植物生长的影响。结果表明，植物种类与盆栽基质的肥力是影响植物幼苗生长的关键因素，而桉叶水抽提物与土壤水分对植物幼苗的生长虽有影响，但与前二相比作用较小。因此，在退化的桉树人工林地重建林下植被，首先应选择耐瘠薄、耐旱性强和对化感作用不敏感的植物，如柱花草等豆科植物，既能自身固氮，又能通过循环增加土壤养分，当然应该注意豆科与禾本科搭配。结果还表明，在逆境条件下，桉树的化感作用会增强，并与其它因素互相作用，抑制林下植被生长。     

牧草化感作用抑草方式及新型除草剂研究进展

利用牧草的化感抑草作用防治田间杂草，即通过提取牧草活性物质、利用其残渣覆盖土壤或利用伴生植物生长等方式抑制杂草生长。目前已经鉴定出很多有化感抑草作用的物质，利用这些物质合成新型的除草剂，可达到生物防除杂草的目的，此方法不会造成环境污染，也不会使害虫产生抗药性。本文综述牧草化感作用的抑草方式、化感物质属性和机理研究及新型除草剂的研究进展，并提出今后牧草化感作用的发展前景。     

植物化感作用研究进展

对植物化感作用物质及其作用机制,以及化感与可持续农林生产、生态系统的关系进行了综述,并提出了化感作用研究的发展前景。     

玉米马铃薯地上部水浸提液对玉米生长的影响

采用盆栽试验,分析玉米间作马铃薯体系中两种作物不同生育时期活体植株地上部水浸提液对玉米生长发育的影响,探讨两种作物地上部水浸提液对玉米的化感效应。结果表明,马铃薯地上部水浸提液对玉米干物重的化感效应强于玉米地上部水浸提液。马铃薯地上部水浸提液对生育期内玉米的株高、茎粗、叶面积均有显著促进作用,对茎、叶干物重有先弱后强的促进作用,对根干物重有先强后弱的促进作用。玉米地上部水浸提液对灌浆期前的玉米株高、茎粗、叶面积均有显著促进作用,对茎、叶和根干物重均有不同程度的促进作用;对灌浆期后的玉米株高、茎粗、叶面积无显著影响,玉米茎和根干物重有抑制作用。马铃薯地上部水浸提液处理的玉米穗干重显著高于玉米水浸提液和水处理,在灌浆期分别高出其90.21%和144.60%,到成熟期分别高出110.98%和151.90%,表明在玉米间作马铃薯体系中,马铃薯地上部对玉米经济产量有显著影响。     

Increases in leaf artemisinin concentration in Artemisia annua in response to the application of phosphorus and boron

Malaria resurgence particularly in the third world is considerable and exacerbated by the development of multi-drug resistances to chemicals such as chloroquinone. Drug therapies, as recommended by WHO include the use of antimalarial compounds derived from Artemisia annua L., i.e. artemisinin-based therapies. This work aims to determine how A. annua plant dry matter can be enhanced while maximising artemisinin concentration from understanding the plant's mineral requirements for P and B. Experiments with differing of P, from 5 to 120 mg L⁻¹ and B from 0.1 to 0.9 mg L⁻¹ were undertaken. Mineral nutrients were supplied in irrigation water to potted plants and after a period of growth, dry matter production and leaf artemisinin concentration were determined. Increases in P application enhanced plant growth and total dry matter production. An optimal application rate, with respect to dry matter, was apparent around 30 mg P L⁻¹. Despite increases in P application having no influence on leaf artemisinin concentration, optimal yields of artemisinin, on a per plant basis, were again achieved at supply rate around 30-60 mg L⁻¹. Increasing B application rate had little influence on dry matter production despite increases in B leaf tissue concentration promoting the total amount of B per plant. Leaf artemisinin concentration significantly increased with B application rate up to 0.6 mg B L⁻¹. The higher artemisinin concentrations when multiplied by total leaf dry matter at the higher B application rates produced an increase in total artemisinin production per plant. There was however no further significant effect on leaf artemisinin concentration when B supply concentrations increased further (0.9 mg L⁻¹). Artemisinin production varied between the two experiments to a greater extent than plant dry matter production and the reasons for this are discussed in relation to growing environments and their possible impacts on artemisinin biosynthesis.     

Crop Allelopathy and Its Role in Ecological Agriculture

Summary

A number of crops exhibit allelopathic interactions that play a significant role in the complex environment of agroecosystems. Several studies have shown that allelopathic crops reduce growth, development and yield of other crops growing simultaneously or subsequently in the fields. Another aspect of interest regarding crop allelopathy is that allelochemicals may exhibit inhibitory effect on the same crop which is commonly called as crop autotoxicity. It is predominantly common in fields where sole cropping under reduced or no-tillage system is practiced. Though any crop part can be allelopathic, including even the pollens, but decomposing crop residues exhibit more influence on other plants. Furthermore, the extent of allelopathy by a crop plant varies with age, part and type of cultivar being used. Nowadays allelo-pathic crops are being used as an important tool in managing weeds and harmful pests under sustainable pest management programs. In this context several cover/smother and green manure crops with allelopathic nature hold a good promise as well as challenge for the future as they have a potential to suppress noxious weeds. Likewise, the decomposing residues of such crops can also be used for managing harmful weeds and pests vis-à-vis maintaining the sustainability of the system. The traditional practice of crop rotation which declined with the discovery of synthetic herbicides can also be revived, if allelopathic potential of rotational crops is well understood. Selection of cultivars with high allelopathic potential/high competitiveness is another possible way by which crop allelopathy can be better utilized for weed control and yield enhancement. Crops with less allelopathic potential can be genetically improved by incorporating desired genes encoding the synthesis of allelochemicals. Pure allelochemicals extracted and identified from some crop plants can also be used as bioherbicides.     

Weed Allelopathy,Its Ecological Impacts and Future Prospects

Summary

The importance, characteristics, positive and negative impacts, and future role of weeds as an integral part of the natural and agroecosystems are evaluated and discussed. Interference between plants in nature and the importance of differentiating between competition and allelopathy are interpreted. Allelopathy as one component of weed/crop interference, allelochemicals from weed species and their possible mechanism of action are listed and discussed. Weed species with inhibitory action against cultivated crops, other weed species, and plant pathogens, as well as self-inhibitory (autopathic) species are reviewed. Stimulatory or inhibitory allelopathic effects of different crop plants, trapping and catching species, and the potential of allelopathic weeds in inhibiting or stimulating certain parasitic weed species are discussed and evaluated. Allelopathy as a mechanism and future strategy for agricultural pest control and farm management and the potential use and development of some allelochemicals as natural pesticides or plant growth regulators are also considered and discussed.     

圆叶牵牛对小麦种子的化感作用研究

为了给入侵杂草圆叶牵牛的综合治理提供参考依据,采用生物测定法研究了圆叶牵牛水浸提液对三个小麦品种种子萌发和幼苗生长的影响。结果表明,圆叶牵牛内存在化感物质,浸提液处理降低了三个供试小麦品种的发芽率、根长、苗高、活力指数,抑制作用随浓度的升高而增强。小麦幼苗生长对浸提液反应更为敏感,浸提液对幼苗生长的抑制作用大于对种子萌发的抑制作用。相同浓度的浸提液对三个小麦品种的影响程度存在差异,石麦18抗性较强。     

山药化感物质对山药和玉米种子萌发及幼苗生长的影响

本研究以山药零余子和玉米种子为受体材料,采用生物测试方法,以发芽率、发芽势、发芽指数、根长、茎长和干重为种子萌发和幼苗生长参数,研究山药植株腐解液、根系分泌物和根际土浸提液对受体材料的化感效应,旨在探明山药化感物质的释放途径,探索山药化感物质对不同受体材料的化感作用,为揭示山药连作障碍的机理奠定基础。结果表明：山药植株腐解液和根系分泌物对山药和玉米均有强烈的化感抑制作用,根际土浸提液的化感作用较微弱,化感作用强度为根系分泌物˃植株腐解液˃根际土浸提液,山药根系分泌物和植株腐解液含有丰富的化感物质,可能是山药自毒物质的主要来源之一,是山药化感物质研究的可靠基础材料;在试验设置的浓度范围内,山药化感物质对受体材料的抑制作用与其质量浓度呈正比,3种浸提液对受试材料的化感作用存在低促高抑的浓度效应,低于100 mg/mL时有微弱的促进作用,大于等于100 mg/mL就会产生强烈的抑制作用,随着浓度升高,化感抑制作用强度越大;山药的化感物质对玉米幼苗生长抑制强度大于种子萌发期,山药则相反;结合种子萌发和幼苗生长的综合化感效应指数,2种受试作物对山药化感作用的敏感程度为自毒作用强于他感作用。     

扦插时期、光照与密度等条件在马铃薯微型薯生产中的影响

在马铃薯微型薯生产过程中,扦插时期不同,使马铃薯植株不同物候期所处的环境条件不同,严重影响植株生物学性状及微型薯产量。试管苗扦插生根主要受温度影响,光照通过影响温、湿度对生根起作用。密度不同,植株生长受到影响,微型薯数量与产量均不同。     

Allelopathy and Its Implications in Agroecosystems

Summary

Allelopathy includes both positive and negative effects of one plant on the other through environment, though most of the studies seem to focus on its deleterious impacts. It plays a key role in both natural and managed ecosystems. In agroecosystems, several weeds, crops, agroforestry trees and fruit trees have been shown to exert allelopathic influence on the crops, thus, affecting their germination and growth adversely. Some of the agricultural and horticultural crops affect their own seedlings grown in succession which is commonly known as replant problem/syndrome. Available studies indicate that allelochemicals act via bringing certain changes in physiological functions like respiration, photosynthesis and ion uptake. These, in turn, result in visible changes in seed germination, further growth reduction and overall performance of the target plants. The studies on interplant interactions assume significance in agroforestry programmes for selecting the types of crops complementary to the selective tree species. In the recent past, however, scientific attention has also been drawn to exploit the positive significant roles this phenomenon can play in enhancing crop productivity. In this context, we discuss the tremendous scope of allelopathy towards weed and pest management, apart from nitrogen conservation, and synthesis of novel agrochemicals based on natural product chemistry. The use of natural products of plant or microbial origin as pesticides/herbicides have gained much attention of the scientists as they offer many advantages over synthetic chemicals. The production of such chemicals should be enhanced by devising suitable protocols based on biotechnological procedures for their widespread utilization.     

青蒿素对小麦种子萌发及幼苗生长的影响

为了解青蒿素对小麦种子萌发和幼苗生长的影响,运用室内培养皿法,分析了不同浓度的青蒿素溶液浸种后小麦种子发芽率及幼苗高度、根长、整株鲜重、根和茎鲜重及干重、根系活力等指标的变化。结果表明,青蒿素对小麦种子萌发及幼苗生长有抑制作用,且浓度越高,抑制作用越显著。与无菌水对照相比,青蒿素浸种处理显著降低了小麦的种子发芽率、苗高、根长、根鲜重和茎的鲜、干重,增加了根干重和根冠比。小麦的根系活力和可溶性蛋白含量随青蒿素浓度的增加而递减,可溶性糖含量则随之递增,叶绿素含量则呈先升高后降低的趋势,以20mg·L-1处理含量最高。此外,青蒿素浸种处理对小麦幼苗各项指标的影响与15mg·L-1多效唑相似。