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作 者 ：康云艳;郭世荣;段九菊

期 刊 ：应用生态学报 2008年 19卷 03期 页码：583-587

关键词：黄瓜；

摘 要 ：采用营养液栽培方法，研究了低氧胁迫对两个耐低氧能力不同的黄瓜品种根系呼吸代谢的影响.结果表明：低氧胁迫下，两个黄瓜品种根系三羧酸循环显著受阻，无氧呼吸代谢被促进.与耐低氧能力较弱的中农8号相比，耐低氧能力较强的绿霸春4号根系琥珀酸脱氢酶和异柠檬酸脱氢酶活性的降低幅度较小，乳酸脱氢酶活性、乳酸和丙酮酸含量的增加幅度较小，而丙酮酸脱羧酶、乙醇脱氢酶活性及乙醇、丙氨酸含量的增加幅度较大；低氧胁迫8 d时，与相应对照相比，绿霸春4号根系乙醇脱氢酶活性及乙醇和丙氨酸含量分别增加了409.30%、112.13%和30.64%，中农8号根系分别增加了110.42%、31.84%和4.78%，这是两个黄瓜品种耐低氧能力差异的主要生理原因.两品种幼苗根系丙氨酸氨基转移酶活性和乙醛含量没有显著差异.表明低氧胁迫下黄瓜根系乙醇发酵代谢途径的增强和丙氨酸的积累有利于防御低氧伤害.

Abstract:With the seedlings of Lübachun No.4, a hypoxia-resistant cultivar, and Zhongnong No.8, a hypoxia-sensitive cultivar, as test materials, and by the method of solution culture, this paper studied the effects of root zone hypoxia on their roots’ respiratory metabolism. The results showed that root zone hypoxia inhibited the tricarboxylic acid (TCA) cycle significantly, but accelerated the anaerobic respiration of cucumber roots. Under root zone hypoxia stress, the decrement of succinic dehydrogenase (SDH) and isocitric dehydrogenase (IDH) activities and the increment of lactate dehydrogenase (LDH) activity and lactate and pyruvate contents were lesser in Lübachun No.4 than in Zhongnong No.8 seedlings roots, but conversely, the increment of pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) activities and alcohol and alanine contents in Lübachun No.4 seedlings roots were higher than those in Zhongnong No.8 seedlings roots. On the 8th day of hypoxia stress, the ADH activity and alcohol and alanine contents increased by 409.30%, 112.13% and 30.64% in Lübachun No.4 roots and by 110.42%, 31.84% and 4.78% in Zhongnong No.8 roots, respectively, compared with the control. No significant differences in the alanine aminotransferase (AlaAT) activity and acetaldehyde content were observed between the two cultivars. It was concluded that the acceleration of alcohol fermentation and the accumulation of alanine were in favor of the enhancement of root zone hypoxia tolerance of cucumber roots.

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