Screening and Physiology of Chinese Cabbage (Brassica campestris L. spp. pekinensis) Responding to High Temperature and Waterlogging
Date Issued
2012
Date
2012
Author(s)
Shie, Ming-Fang
Abstract
Chinese cabbage (Brassica campestris L. spp. pekinensis) is a cool-season vegetable of Brassica species in Cruciferae family. Chinese cabbage is not suitable to cultivate in summer of Taiwan due to the optimal growth temperature being 10~22℃. Heat tolerant Chinese cabbage cultivars can grow and develop a tight head at average temperature over 25℃. However, high temperature, typhoon and heavy rainfall affect vegetable production in summer of Taiwan. The loss sum of Chinese cabbage in 2009 was about NT$30,000,000. In this research, tolerances of 40 Chinese cabbage cultivars to waterlogging in summer were studied. The seedling growth and physiology of cultivars with very different tolerances to heat and waterlogging were investigated. According to the field yields after waterlogging in summer, the highest yielding ‘Ching-Long 200’ and AV86188, higher yielding ‘ASVEG#2’,‘No. 47’ and ‘Yu-Fong’, and the lowest yielding ‘Ruey-Long 720’ were selected from 40 cultivars. These six cultivars were sown and grown in growth chamber under20/15℃for 3 weeks. Then seedlings were treated with 20/15℃ non-waterlogging, 20/15℃waterlogging, 40/30℃ non-waterlogging and 40/30℃waterlogging. Afterwards seedlings were transferred to 20/15℃and drained as for recovery stage. On the 8th day of recovery, the leaf area, fresh weight and dry weight of ASVEG#2’, ‘No. 47’ and ‘Ruey-Long 720’ were significantly lower after heat and waterlogging treatments. ‘Ching-Long 200’ and ‘Yu-Fong’ showed better seedling growth. The electrolyte leakage ratio of ‘No. 47’ and ‘Ruey-Long 720’ increased significantly under heat stress. The 40/30℃ non-waterlogging treatment affected the chlorophyll contents of Chinese cabbage seriously. Heat stress also affected the leaf color of new born leaves. Fv/Fm values of 6 cultivars decreased significantly under heat stress and raised on the 2nd day of recovery. However, the photosynthetic rates of AV86188 and ‘Ruey-Long 720’, as stomatal conductance and transpirational rate, were significantly lower than control on the 4th day of recovery. The malondialdehyde and total peroxide contents of heat and waterlogging sensitive ‘Ruey-Long 720’ were significantly higher than tolerant ‘Ching-Long 200’ after heat and waterlogging treatment. The proline content of ‘Ching-Long 200’ accumulated to a significantly higher value of 1.1 μmol/g after 24hour stress treatment. The catalase activity of ‘Ching-Long 200’ significantly increased after 48 hours of both non-waterlogging and waterlogging at 40/30℃treatment, while ‘Ruey-Long 720’ did not show significant difference. The activity of ascorbate peroxidase of ‘Ching-Long 200’ increased earlier after 40/30℃ non-waterlogging treatment. According to these results, the expression of fresh weight, dry weight, malondialdehyde and proline contents, and catalase activity of seedlings were similar to the yield of waterlogging trials in summer. These parameters might have potentials as screening index for heat and waterlogging tolerance of Chinese cabbage.
Subjects
Chinese cabbage
heat stress
waterlogging stress
electrolyte leakage
chlorophyll fluorescence
photosynthetic rate
malondialdehye
proline
catalase
Type
thesis
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