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以甘肃庆阳黄土高原地区草田轮作系统中苜蓿 (Med icag o sativa)和小麦 (Triticum aestivum)为研究材料 ,分别于 2 0 0 2年两种作物的拔节期 (分枝期 )、开花期、成熟期和幼苗期 (第 3茬分枝期 )取样 ,分离、鉴定了根部入侵真菌 ,测定了分离所得根部入侵真菌对其寄主作物及另一种轮作作物的致病力。结果表明 :在试验区内共分离到 2 7种根部入侵真菌 ,包括自小麦根系分离到 2 6种 ,苜蓿侧根分离到 2 3种 ,其中 2 2种为苜蓿和小麦共同的根部入侵真菌。两种作物根部入侵真菌区系中优势种明显不同 ,苜蓿根部最主要的 5种入侵真菌按分离率的高低依次为尖镰孢 (Fusarium oxysporum) 17.0 %、大孢肉座菌 (Selinia sp.)15.4%、茎点霉 (Phoma medicaginis) 9.5%、腐皮镰孢 (F usarium solani) 6.7%及柱孢 (Cylindrocarp on destructans) 6.6% ;而小麦根部 5种最主要的入侵真菌按分离率的高低依次为黑团孢 (Periconia sp.) 15.0 %、丝葚霉 (Pap ulaspora sp.) 12 .1%、多主枝孢(Cladosporium herbarum) 5.4%、丝核菌 (Rhizoctonia sp.) 4.0 %及尖镰孢 3 .9% ;总的真菌分离率亦是苜蓿高于小麦。苜蓿与小麦的根段带菌率均有随生长季的延长而增高的特征。在试验条件下 ,参试的苜蓿、小麦根部入侵真菌对苜蓿和小麦均?
Taking Medicago sativa and Triticum aestivum in grassland rotation system in Qingyang loess plateau of Gansu Province as research materials, the effects of jointing stage (branching stage), flowering stage, At the ripening and seedling stage (the third stubble stage), the root invaded fungi were sampled, isolated and identified. The pathogenicity of the isolated roots to the host crop and another crop was determined. The results showed that 27 kinds of root invaded fungi were isolated in the experimental area, including 26 species isolated from wheat roots and 23 species isolated from lateral roots of alfalfa, of which 22 species were the common root invaded fungi of alfalfa and wheat. The dominant species of fungi invaded by the two crops were significantly different. The five major fungi in the roots of alfalfa were 17.0% Fusarium oxysporum, Selinia sp. 15.4%, Phoma medicaginis 9.5%, Fusarium solani 6.7% and Cylindrocarp on destructans 6.6%, while the five main invasive fungi in wheat root were classified according to the isolation rate Followed by Periconia sp. 15.0%, Papulaspora sp. 12.1%, Cladosporium herbarum 5.4%, Rhizoctonia sp. 4.0% and tip Fusarium was 3.9%. The total fungal isolation rate was also higher in alfalfa than in wheat. Root zone of alfalfa and wheat with the growth rate of the bacterium were increased with the extension of the characteristics. Under the experimental conditions, the tested alfalfa and wheat root invading fungi were alfalfa and wheat both?