Cropping systems for the management of phytonematodes     

R. Rodríguez-kábana  Graciela H. Canullo 《Phytoparasitica》1992,20(3):211-224

Damage caused by nematodes is one of the limiting factors in crop production. Traditional nematode management is based on the use of crop rotations, resistant cultivars, nematicides, or combinations of these methods. For a crop like peanut (Arachis hypogaea), cultivars resistant to root-knot nematodes are not available. There are soybean (Glycine max) cultivars resistant to some of the species of root-knot nematodes (Meloidogyne spp.); however, most fields have nematode infestations composed of mixtures of species. Research at Auburn has shown that tropical crops can be used effectively in rotation to manage nematode problems. Rotations with American jointvetch (Aeschynomene americana), castor (Ricinus communis), hairy indigo (Indigofera hirsuta), partridge pea (Cassia fasciculata), sesame (Sesamum indicum), and velvetbean (Mucuna deeringiana) have resulted in good nematode control and increased yields of peanut and soybean. Some crops (castor, sesame) are considered ‘active’ in that they produce compounds that are nematicidal, whereas others (e.g. corn, sorghum) are simply non-host, that is, ‘passive’.  相似文献   

微孔草叶细胞冻害研究   总被引：5，自引：0，他引：5  

王钦  尚可政 《草业科学》1998,15(3):23-26,31

针对微孔草常因低温环境而受到冻害,造成产量下降的问题,用电导法测其渗出液的电导率,计算渗出电解质百分率即细胞伤害率并配以Ｌｏｇｉｓｔｉｃ方程求其拐点温度及半致死温度的定量范围,以确定其抗寒能力。结果表明,微孔草叶组织在０．５ｈ低温处理的半致死温度是－１０．７９℃,１．０ｈ处理是－７．０１℃,１．５ｈ处理是－１．６８℃,由此认为,微孔草是中等抗寒植物,测量渗出液的电导率是一种定量估计冻害的好方法。  相似文献   

Allelopathy in crop/weed interactions--an update     

Belz RG 《Pest management science》2007,63(4):308-326

Since varietal differences in allelopathy of crops against weeds were discovered in the 1970s, much research has documented the potential that allelopathic crops offer for integrated weed management with substantially reduced herbicide rates. Research groups worldwide have identified several crop species possessing potent allelopathic interference mediated by root exudation of allelochemicals. Rice, wheat, barley and sorghum have attracted most attention. Past research focused on germplasm screening for elite allelopathic cultivars and the identification of the allelochemicals involved. Based on this, traditional breeding efforts were initiated in rice and wheat to breed agronomically acceptable, weed-suppressive cultivars with improved allelopathic interference. Promising suppressive crosses are under investigation. Molecular approaches have elucidated the genetics of allelopathy by QTL mapping which associated the trait in rice and wheat with several chromosomes and suggested the involvement of several allelochemicals. Potentially important compounds that are constitutively secreted from roots have been identified in all crop species under investigation. Biosynthesis and exudation of these metabolites follow a distinct temporal pattern and can be induced by biotic and abiotic factors. The current state of knowledge suggests that allelopathy involves fluctuating mixtures of allelochemicals and their metabolites as regulated by genotype and developmental stage of the producing plant, environment, cultivation and signalling effects, as well as the chemical or microbial turnover of compounds in the rhizosphere. Functional genomics is being applied to identify genes involved in biosynthesis of several identified allelochemicals, providing the potential to improve allelopathy by molecular breeding. The dynamics of crop allelopathy, inducible processes and plant signalling is gaining growing attention; however, future research should also consider allelochemical release mechanisms, persistence, selectivity and modes of action, as well as consequences of improved crop allelopathy on plant physiology, the environment and management strategies. Creation of weed-suppressive cultivars with improved allelopathic interference is still a challenge, but traditional breeding or biotechnology should pave the way.  相似文献   

人参根系分泌物对其根源愈伤组织生长及保护酶活性的影响     

杨莉  刘芳君  张一鸣  韩梅  杨利民 《吉林农业大学学报》2014,(5)

以人参根源愈伤组织为受体,分析了无土栽培条件下收集的人参原生根系分泌物的自毒作用。结果表明:人参根系分泌物可抑制愈伤组织的生长,且随处理浓度增加,抑制活性增强,质量浓度为200 mg/L时,生物量降低56.1%,与对照差异显著;可影响受体抗逆酶活性强弱及变化趋势,短时间或低浓度处理下,酶活性增加,其中超氧化物歧化酶活性增加幅度最大,其次为过氧化物酶和过氧化氢酶,而长时间或中高浓度处理后,酶活性均显著降低,同时3种酶原有的协调作用关系及平衡被破坏。人参原生根系分泌物具有化感自毒活性,对受体抗逆酶系统的显著影响是人参根系分泌物化感活性的重要表现。  相似文献   

根分泌物及其在植物营养中的作用 Ⅱ.锌营养状况对禾本科植物根分泌物的影响     

张福锁 《中国农业大学学报》1991,(4):67-70

研究了在控制条件下,锌营养状况对禾本科植物根系分泌低分子量有机物质及其分泌物对活化难溶性锌和铁的能力的影响。缺锌虽然导致玉米、小麦和大麦根系分泌氨基酸、糖类化合物和酚类化合物增多,但这一变化与它们对难溶性锌和铁的活化作用无关。禾本科植物氨基酸、糖类化合物和酚类化合物的分泌率随着苗龄和缺锌程度的增加而减少,同时也随生长介质中锌浓度的增加而降低。但是,禾本科植物根分泌物对难溶性锌和铁的活化能力不同于双子叶植物。缺锌小麦的根分泌物不仅可以活化石灰性土壤中的难溶性锌,而且可以活化新沉淀的难溶性铁。与对照植物相比较,其活化能力增加了13～14倍。缺锌导致根系分泌锌和铁的活化物质在植物营养方面有重要意义。  相似文献   

国槐、剌槐幼苗根系固氮酶活性的研究     

唐敏 《北京林业大学学报》1991,(3)

研究了刺槐(Robinia pseudoacacia)、国槐(Sophora japonica)一年生幼苗根系固氮酶活性的季节性变化,并且通过植物离体根尖接种根瘤菌试验和分析植物根系分泌物反映了国槐、刺槐根系固氮的某些特性。  相似文献   

培养液化学成分变化及其对水培茶树生长的影响     

徐月荣  梁月荣  奚彪  刘祖生 《浙江大学学报(农业与生命科学版)》1995,(5)

水培过程中营养液中的ＮＨ＿４－Ｎ浓度下降伴随ＮＯ＿３－Ｎ浓度提高，培养过程中溶液活性Ａｌ含量下降，ｐＨ值降低并非活性Ａｌ浓度提高所致，培养液加Ａｌ对ｐＨ下降有缓冲作用。茶树根系分泌物中有咖啡因和儿茶素类物质，利用培养过茶树的营养液再次培养茶苗，即使通过添加速效Ｎ、Ｐ、Ｋ保持其营养水平，茶树生长仍然受到抑制。据此推断，茶树根系分泌物中的咖啡因和儿茶素类物质具有异株克生作用。  相似文献   

黄瓜砧木对南方根结线虫生长发育的影响及其与根系分泌物的关系   总被引：1，自引：0，他引：1  

王艳艳  辛国凤  魏珉  李岩  王秀峰  史庆华  杨凤娟 《中国生态农业学报》2015,23(7):900-905

黄瓜是设施主栽蔬菜,长期连作导致根结线虫病发生和危害加重;嫁接是提高黄瓜对根结线虫抗性的有效手段,但不同砧木品种间存在差异。为探明嫁接提高黄瓜抗根结线虫能力的机制,试验选用不同抗性的砧木品种‘云南黑籽南瓜’(低感)和‘甜砧南瓜’(高感),以‘新泰密刺’自根黄瓜为对照,采用人工接种,研究了黄瓜砧木对南方根结线虫生长和繁殖的影响,并探讨了根系分泌物与线虫卵孵化的关系。结果表明:线虫侵染初期,3个品种根内的二龄幼虫(J2)数差异显著,‘云南黑籽南瓜’最少,‘甜砧南瓜’次之,‘新泰密刺’最多;侵入根内的J2均能正常发育为成虫,根内线虫总数以‘云南黑籽南瓜’最少,‘新泰密刺’最多;根际J2数量以‘新泰密刺’最多,‘云南黑籽南瓜’最少;发生二次侵染前,根际卵粒数呈现出相同的特点。黄瓜及其砧木根系分泌物明显影响根结线虫卵的孵化,孵化率以‘云南黑籽南瓜’最低,‘甜砧南瓜’次之,‘新泰密刺’最高;接种根结线虫后,根系分泌物影响下的卵孵化率较未接种时明显增加,‘新泰密刺’增幅最大,‘云南黑籽南瓜’增幅最小;随着生育时间延长,三者根系分泌物对卵孵化的促进作用逐渐增强。低感砧木根系分泌物对南方根结线虫卵孵化具有明显的抑制作用,可显著降低线虫在其根内及根际的发育,可能是抗线虫的机制之一。  相似文献   

Germination of <Emphasis Type="Italic">Plasmodiophora brassicae</Emphasis> resting spores stimulated by a non-host plant     

Hanna?FribergEmail author  Jan?Lagerl?f  Birgitta?R?mert 《European journal of plant pathology / European Foundation for Plant Pathology》2005,113(3):275-281

Plant-induced germination of Plasmodiophora brassicae resting spores was studied in a laboratory experiment. Spore reaction was analysed in nutrient solution with exudates from growing roots of different plant species – one host plant (Brassica rapa var. pekinensis) and four non-host plants (Lolium perenne, Allium porrum, Secale cereale and Trifolium pratense) – and in controls with distilled water and nutrient solution. It was found that root exudates from L. perenne stimulated spore germination more than exudates from the other plants, including those from the host plant. The effect could not be explained by differences in the nutritional composition of the solutions due to differential uptake of the plant species, or by differences in root activity, measured as exudation of soluble sugars. This is the first time such a separation of factors has been done in analysing the influence of plants on P. brassicae germination. Although stimulation of P. brassicae resting spore germination is not restricted to the presence of host plants, it seems to vary depending on the plant species.  相似文献   

烟草自毒效应的品种间差异研究(英文)     

许露露  潘文杰  张国平 《浙江大学学报(农业与生命科学版)》2012,(2):119-126

利用生物测试法研究8个烟草品种(系)根系分泌物的自毒效应。结果表明:大多数供试烟草品种的幼苗鲜质量、干质量、最大叶片长和根长随着根系分泌物浓度的升高而减少,且品种间差异明显,其中黔西1号在稀释1倍的水平下,以上生长指标抑制率分别为63.3%、34.3%、42.4%和30.8%,居各品种之首;但新品系1号表现为以上生长参数均随着提取液浓度的升高而增大,在稀释1倍水平下生长促进率分别为13.0%、51.8%、13.0%和16.7%;此外,新品系7号、1号和品种云烟85和春雷3号的发芽率受根系分泌物的促进,而其他品种则受抑制;生物测试结果显示,在供试的8个品种中,自毒作用以新品系1号最弱,黔西1号最强。可见,自毒作用在烟草品种间差异明显,栽培上应选择适宜的烟草品种以减少自毒作用引起的连作障碍。  相似文献