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宁夏豆科植物根瘤菌资源调查及其生态分布 总被引：3，自引：2，他引：1
通过对宁夏野生及栽培豆科植物结瘤固氮资源的调查,从24属47种豆科植物根部采集到根瘤样品748份,通过调查显示:兴隆山棘豆和单叶黄芪为新发现的豆科结瘤植物;此地区根瘤主要为黄色或褐色,性状以球形和棒状为主,主要着生在侧根;影响宁夏豆科植物结瘤的因素有水分、土壤肥力和植物的生育阶段;根据生长习性、地理分布和利用状况,将宁夏豆科植物根瘤菌资源分为干旱区、山坡草地区和耕地区. 相似文献
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对祁连山部分地区豆科植物根瘤菌资源进行了调查,从9属32种野生豆科植物根部采集到根瘤样品427份。调查结果显示:调查区豆科植物资源种类丰富,所采集根瘤形状多为棒状、掌状及不规则状,颜色以粉色和黄色为主,着生部位主要为侧根;影响该区豆科植物结瘤的因素除与寄主植物生育阶段及遗传特性有关外,还与地形、土壤、气候、生物及人为因子等多种生态因素密切相关,其中地形及土壤是影响结瘤的关键因子。 相似文献
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玄参科马先蒿的结瘤固氮现象 总被引：1，自引：1，他引：1
笔者在进行豆科植物根瘤菌资源考察时，在甘肃民乐县发现玄参科马先蒿可以形成根瘤，并具有乙炔还原活性。玄参科植物的结瘤固氮现象未见文献记载（文献查至１９９０年）。 相似文献
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沙坡头地区豆科植物共生固氮资源初步研究 总被引：4，自引：0，他引：4
对沙坡头地区引进和野生的１９属５１种豆科植物的结瘤固氮状况进行了调查，除花生，三刺皂荚，铃铛刺３属３种外，其余４８种均能自然结瘤，种的结瘤率为９４．１％，其中２７种为Ａｌｌｅｎ文献中未记载的结瘤豆科植物。根瘤形态大多数圆形，棒状域指状，形态较为规则，白色黄色者居多，乙炔还原活力测定表明，２４．６％为无效根瘤，不同种豆科植物根瘤的乙炔还原活力相差不大，一般活力都较低，乙炔还原活力小于１μｍｏｌＣ２Ｈ 相似文献
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甘肃中西部豆科植物根瘤菌多样性调查研究 总被引：4，自引：3，他引：1
通过对甘肃中西部地区豆科植物共生固氮资源多样性的调查,共获得豆科植物根瘤样品452份,涉及18个属,30个种,分离得到328株根瘤菌。调查结果显示：（1）本地区豆科植物资源贫乏,但适应性强,大多数都具有抗干旱、耐盐耐碱特性。（2）土壤干旱和土壤高盐浓度是影响根瘤形成的重要限制因子。（3）本地区豆科植物根瘤形状多为棒状、球状,部分为不规则状;颜色为红色、浅褐色、褐色、黄色,部分为白色、黑色。（4）许多豆科植物——根瘤菌共生固氮体系已被广泛应用于防风固沙、防治水土流失及改善生态环境等方面。 相似文献
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甘肃宁夏根瘤菌的分离及回接鉴定 总被引：3，自引：0，他引：3
从甘肃宁夏干旱地区３６属９８种豆种植物４００余个根瘤样品中分离得到３６０株根瘤菌，总分离率为８７％，以２０属２２种寄主植物对大部分菌株进行了回接验证，回接结瘤率８１．２％，对干埋地区概胶斩采集，根菌的分离及回接技术进行了讨论。 相似文献
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新疆干旱区短命豆科植物弯果胡卢巴结瘤固氮的研究 总被引：3，自引：0，他引：3
弯果胡卢巴(Trigonella arcuata)是新疆干旱地区的短命豆科植物,生长于早春,生活周期短,约两个月,在盛夏之前就完成了它的一生。它能结瘤固氮,固氮活性变幅较宽。与一般豆科植物不同,苗后期它的根瘤固氮活性最高。根瘤固氮活性受环境条件影响较大,特别是土壤水分条件是植物根瘤固氮活性表达的重要因素。弯果胡卢巴根瘤内存在着吸氢酶体系,在固氮酶作用下,伴随氮的还原而产生的氢气,可以再循环利用,提高了固氮的相对效率。虽然弯果胡卢巴根瘤在各生育期不放氢,固氮效率为1,但是其根瘤内吸氢酶活性与植物生育期有相关性,初花期活性最高。此外,本文对弯果胡卢巴结瘤固氮的生理生态特征及其开发利用的价值进行了讨论。 相似文献
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大豆接种根瘤菌,在生茬地上种植多表现出一定的增产效果,但在重茬豆田接种,效果则下降,甚至难以表现增产效果,这已被众多的实验所证实。近年来一些报导指出,大豆根廇菌接种效果之所以较差,有的是因土著根瘤菌数量多,竞争力强,导致接入菌种不能占据结瘤位置,有的是因接入菌种与栽培的大豆品种间亲合力较差,根瘤菌不易进入大豆根内,不能形成有力的共生固氮体系。为了探讨土著根瘤菌对生茬地和轮播地大豆的结瘤固氮关系。1984年我们对石河子地区145团8号田大豆的自然结瘤、固氮情况进行了调查,以提供在石河子地区有效地接种大豆根瘤菌的依据。 相似文献
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P. Oyarzun M. Gerlagh A. E. Hoogland 《European journal of plant pathology / European Foundation for Plant Pathology》1993,99(1):35-44
The relation between the frequency of legume crops in a rotation and the root rot severity in pea was examined in a field survey. Additionally, greenhouse experiments were performed with soil samples from legume rotation trials or from farmers' fields. The frequency of pea crops in current rotations proved to be much less than the recommended value of one in six years. The correlation between pea root rot and the number of years that pea or other legumes were not grown on the field under consideration (called crop interval) was weak. Root rot severity correlated better with the frequency of peas or legumes in general over a period of 18 years, but the frequency still explained only a minor fraction of the variation in disease index. Some experimental data pointed to the occurrence of a highly specific pathogen microflora with continuous cropping of only one legume species, but this phenomenon probably does not occur in farmers' fields. In field samples, root disease index for pea correlated well with that for field bean. The survival of resting structures of pathogens such asAphanomyces euteiches probably explains why the frequency of legume cropping has a higher impact than crop interval on root disease incidence. Pea-free periods and legume frequencies have a poor predictive value for crop management purposes. 相似文献
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Critical factors driving aphanomyces damping‐off and root disease in clover revealed and explained using linear and generalized linear models and boosted regression trees 
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下载免费PDF全文 Subterranean clover (Trifolium subterraneum) is an important forage legume in Mediterranean regions worldwide. Aphanomyces damping‐off and root disease (Aphanomyces trifolii) poses significant threat to its persistence and productivity. Studies were conducted to define how environmental explanatory variables (temperature, soil type, moisture, nutrition) and variety influence disease severity and consequent forage productivity and persistence. Relationships were modelled using linear and generalized linear models and boosted regression trees. Linear modelling highlighted complex relationships between environmental variables and each dependent variable (emergence, tap and lateral root disease, dry shoot and root weight). All environmental variables produced significant interaction and/or main effects within each dependent variable. Boosted regression trees supported the complex nature of relationships in linear models, with temperature and either soil or variety most, and nutrition least, influential. Heat maps showed more disease for low temperatures. Least tap root disease was under high temperatures, while least lateral root disease was under medium or high temperatures, low moisture, and in sand‐based soil. These are the first studies using modelling approaches to reveal the complexities of how fluctuating soil temperature, moisture and nutrition conditions, and soil type and variety, determine aphanomyces damping‐off and root disease severity and resultant adverse impacts on forage legume productivity and persistence. Outcomes are widely applicable across soilborne oomycete pathogens of forage legumes. Studies highlighted how warming temperatures and drying climate associated with climate change should reduce future impact and importance of this and other soilborne oomycete diseases of forage legumes favoured by cold temperatures and wet and waterlogged conditions. 相似文献
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ABSTRACT Relatively little is known about the population biology of the legume pathogen Aphanomyces euteiches. A. euteiches is a soilborne pathogen causing Aphanomyces root rot of several legumes, including alfalfa, bean, lentil, and pea. Our objectives were to assess the degree of diversity, selfing, and population differentiation in A. euteiches. We contrasted populations within and among two geographically separated fields with a history of pea production. Molecular genotyping relied on amplified fragment length polymorphism analysis. Samples of A. euteiches recovered from two fields in northeast Oregon and western Washington confirmed previous reports of moderately high genetic diversity in populations of A. euteiches at the regional scale, but revealed higher-than-expected genotypic diversity within individual soil samples. Populations of A. euteiches were significantly differentiated at the soil sample, field, and regional level. The population structure appears to be patterned by regular selfing via oospores, a mixed reproductive system including both asexual and sexual reproduction, with occasional migration of novel genotypes or outcrossing. 相似文献
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Faba bean necrotic yellows virus (FBNYV) was isolated from naturally infected faba bean plants in Jordan. The identification was based on host range, mode of transmission, symptomatology and serological properties. FBNYV occurred naturally in several leguminous crops including cultivated legumes and wild forage legumes, such as species of Medicago , Trifolium and Lathyrus . and infected other plant species belonging to the Malvaceae, such as Malva parviflora and Hibiscus esculentus . Such hosts may act as important natural reservoirs for both the virus and its aphid vectors. This is the first report of infection of M. parviflora and H. esculentus with FBNYV. The virus was not recovered from samples taken from some cultivated crops, including squash, cucumber, tomato, eggplant and pepper, growing near to faba bean fields. Also, it was not detected in commercial faba bean seeds collected from local companies or in seeds collected from infected faba bean plants. It was transmitted efficiently by Aphis craccivora . Serological testing of 1392 samples from faba beans showing virus-like symptoms and collected randomly from 16 locations (fields) in the Jordan Valley and Jarash areas showed that FBNYV occurred in 54.5% of the samples. These results indicate that FBNYV was an important pathogen of beans during the growing season of 1996 in Jordan. 相似文献
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ABSTRACT Effects of border cell and root tip exudates on root knot nematode (Meloidogyne incognita) behavior were examined. In whole-plant assays using pea, M. incognita second-stage juveniles (J2) accumulated rapidly around the 1- to 2-mm apical region ensheathed by border cells, but not in the region of elongation. Within 15 to 30 min, J2 which had accumulated within detached clumps of border cells lost motility and entered into a quiescent state. When border cells (and associated root tip exudates) were washed from pea roots prior to challenge with nematodes, no such accumulation and quiescence was induced. Attraction of nematodes by roots was species dependent: no attraction or accumulation occurred in snap bean. Using a quantitative assay, three categories of chemotaxis responses occurred: attraction (pea and alfalfa cv. Thor), repulsion (alfalfa cv. Moapa 69), and no response (snap bean and alfalfa cv. Lahonton). In contrast, total root tip exudates from all three plant species acted as a repellent for M. incognita in the sand assay. An in vitro assay was developed to characterize the induced quiescence response. When total root tip exudate from the tested legumes (as well as corn) was incubated with J2 populations, >80% of the nematodes lost motility. A similar response occurred in Caenorhabditis elegans. Border cell exudates did not induce or contribute to the induction of quiescence. Cocultivation of pea border cells with M. incognita resulted in changes in border cell shape similar to those observed in response to exogenous plant hormones. No such changes occurred in snap bean border cells. Understanding the cell- and host-specific extracellular recognition that occurs between roots and pathogenic nematodes in the early stages before infection occurs could lead to new avenues for disease control. 相似文献
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Aphanomyces root rot ( Aphanomyces euteiches ) has become a very destructive disease in French pea crops since 1993. The host specificity of the French pea-infecting populations of this pathogen was investigated by inoculating pea, common vetch, alfalfa, broad bean and green bean with 91 pea-infecting A. euteiches isolates, originating from the main areas of infestation in France. These isolates were compared to 13 isolates from various countries and hosts (pea, green bean, alfalfa). Virulence phenotypes were defined according to the pathogenicity data on the different hosts: all isolates from France infected two to five legume species, with most infecting pea, vetch, alfalfa and broad bean. Four pathotypes were characterized within the French isolates: one type corresponded to broad host range isolates, the second was composed of isolates preferentially agressive on pea/vetch/alfalfa and weakly aggressive on broad bean, and two others corresponding to more specialized isolates that preferentially infected pea/vetch or pea/vetch/alfalfa. Most isolates from France were preferentially pathogenic on pea, like the pea-infecting isolates from other countries, but were less specialized than the alfalfa- and green bean-infecting isolates from other countries. These results suggest that A. euteiches isolates may be maintained on wild or cultivated legumes other than pea in France. 相似文献
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In winter 2002/2003, a total of 136 root samples from 57 different raspberry stocks in Scotland were examined for the presence of raspberry root rot caused by the fungus‐like pathogen Phytophthora fragariae var. rubi. All stocks had been planted as propagation material entered at different grades in the Scottish certification scheme or had applied for plant passports. For detection, a modified ‘Duncan bait test’ was compared to a nested PCR method. The two tests identified the same infected stocks: PCR detected 10 positive samples from four different stocks, while the bait test picked up two additional positive samples coming from the same four stocks. The two tests had a similar level of reliability in this examination and a recommendation for one or the other depends mainly on the technical equipment and skills available in the laboratory. 相似文献