Effects of hypoxia stress on root respiration metabolic activity of cucumber seedlings

The effect of hypoxia stress on seedlings of two cucumber cultivars, Zhongnong 8 sensitive and Baoyou 1 tolerant, were investigated in order to figure out the variations of several important respiratory enzymes and root respiratory activity under hopoxia stress. The results indicated that activities of alcohol dehydratase (ADH), lactate dehydratase (LDH), nitrate reductase (NR) in root were all induced under hypoxia (O_(2)1.5 mg*L~(-1)). ADH, NR activities and root respiration rate of Baoyou 1 were higher than those of Zhongnong 8. LDH activities in Zhongnong 8 reached the peak at the 3rd day of the treatment, whereas that of Baoyou 1 showed no significant change. The results suggest that high ADH activity and NR activity are important to reduce hypoxia stress.