Identification Of Brassica Napus L.of High Tolerance To Waterlogging And Research On Physiological Adaptability Mechanism To Anaerobiosis

Rapeseed {Brassica. napus L.) is the important oil crops in China. Rapeseed usually plant in winter mainly in southern of China, but the ripening seed frequently experience high temperature and humid conditions due to severe rainfall during seed germination and seedling growing in autum, and lead to waterlogging loss of production seriously. There are two kinds of methods to reduce damage of waterlodging: culture measure, control the soil moisture, and the measure of the breeding. Development of resistant cultivar to the waterlogging is becoming an important breeding object which would make better economic benefits directly and reduce peasants' work load, improve the land utilization ratio, increase peasant's income.1. A new method was developed to evaluate tolerance to waterlogging in rape in this study. ZhongYou821 and GH01, as the experiment materials, the seed sprout in wet filter paper breeding-bed. Afer root grow than lmm, the seed were put into one bottle , fill with the distilled water and sealed for 12h 24h 36h 48h 60h 72h. Then seed is taken out and divided into two group continue to grow in sand bed and paper bed. After grow for 7 d, the seedling length, seedling weight and germination percentage were investigated.The result indicates, with the duration of waterlogging time, fresh weight and dry weight of both GH01 and Zhongyou 821 decreased dramatically. GH01 could not survive in anoxic condition for after 48h while Zhongyou 821 were 72h. Electrical conductivity of leachate increased during anoxic condition, but GH01 with a faster tendency than Zhongyou 821.2.100 lines of rapeseed germplasm were evaluated with the new method. After seedling treated with anoxic condition for 24h, the seedling were translated in a paper bed to continue grow for 7 d, and then, electronical conductivity, relative seedling long, relative seedling weight, relative survivor rate, vigor index were investigated to evaluate the resistance index. Compared with the controls (without anoxic treatment), the root were abnormal with shorter length and without root hair, could not support the seedling. According to vigor index, 10 lines of rapeseed materials were classified into waterlogging resistance group.3. The main injury of waterlogging to the plant is hypoxia stress, it is important to study the physiological characters of different waterlogging resistance rape under the hypoxia. The resistant varieties (YouYan No.7, ZhongShuang No.9,01Za796) and susceptible varieties (G4270, 2001V51, QianZaZW99004) were used to study the different reaction in hypoxia condition. The seedling grew in hydroponics conditon for 3 weeks, then transferred to a container which filled with nitrogen for 48 hours. Compared with the susceptible, the soluble sugar content, praline, SOD activity of the resistance group increased rapidly, but POD and CAT activity dereased.