Effects Of Root-knot Nematode On Physiological And Biochemical Characteristics Of Cucumber In Greenhouse

In recent years, cucumber root-knot disease in greenhouse was more andmore serious, which severely reduced the yield and quality of cucumber, at thesame time the control was difficult. Used the cucumber variety of xintaimici,the experiment was carried out in order to study the effects of nematode onphysiological and biochemical characteristics of cucumber to providetheoretical foundation and reference for disease prevention. Results were asfollows:1. Root-knot nematode infection decreased plant height, dry weight ofleaves and stem dramatically; it made fresh weight of roots increased slowly atthe early growth stage while increased rapidly at the late stage because of thegiant cells; it decreased root activity severely, at the same time, decreasedchlorophyll content and photosynthesis, so affected growth and accumulationof substance in cucumber and finally reduced cucumber yield; M. incognitamade cucumber had higher content of soluble sugar, titratable acid and lowercontent of Vc, free amino acid; higher content of soluble protein in the lownematode density but lower content in the high density. In a word, M.incognitadecreased the quality of cucumber.2. After infected by M.incognita, with the increase of nematode density, cucumber leaves accumulated O₂. , but the change of O₂. in roots was not obvious. At the same time, SOD activity of leaves decreased, SOD activity of roots increased; POD, CAT activity of leaves decreased but activity of roots increased on early days after inoculation; PPO activity increased after first infection and PAL activity increased after third infection; activity of PAL and PPO in roots increased after every inoculation; which reflected resistance to the nematode and the resistance was strong after first infection; MDA content and relative conductivity in leaves and roots increased which indicated that...