采用营养液栽培,研究了根际低氧胁迫下三氟拉嗪(TFP)对两个耐低氧能力不同的黄瓜品种幼苗根系中多胺含量和呼吸代谢的影响.结果表明,单纯低氧下,黄瓜幼苗根系中腐胺(Put)、亚精胺(Spd)和精胺(Spm)含量显著增加,琥珀酸脱氢酶(SDH)活性显著降低,乙醇脱氢酶(ADH)和乳酸脱氢酶(LDH)活性显著提高,乙醇和乳酸含量相应增加;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”幼苗根系ADH活性增加幅度和乙醇含量较高,LDH活性增加幅度、SDH活性降低幅度和乳酸含量较低;与单纯低氧胁迫相比,添加TFP处理能显著降低黄瓜幼苗根系中Spd和Spm含量,增加Put含量,同时,根系中SDH和ADH活性降低,LDH活性增加,乳酸含量升高,植株根系生长受到严重抑制,并且对耐低氧性较强的“绿霸春4号”幼苗伤害程度更加明显.表明在低氧胁迫下,Ca^2+、CaM参与了黄瓜幼苗根系多胺及呼吸代谢过程,TFP处理抑制了Ca^2+·CaM信使功能,从而降低了黄瓜植株耐低氧的能力.表5参25
Calmodulin antagonist ( trifluoperazine TFP) pretreatment was conducted on two cucumber cuhivars ( Cucumis sativus cv. Zhongnong No. 8 and cv. Lubachun No. 4) with different resistances to hypoxia stress. The activities of succinic dehydrogenase (SDH) , lactate dehydrogenase (LDH) and alcohol dehydrogenase (ADH) , and the contents of lactate, ethanol, putrescine (Put) , spermidine (Spd) and spermine (Spm) in cucumber seedling roots were investigated under hypoxia stress in hydroponics culture. The results showed that the contents of Put, Spd, Spm, lactate and ethanol in roots of the two cucumber cuhivar seedlings increased significantly. The activities of LDH and ADH in the two cuhivar seedling roots significantly increased, while the activity of SDH significantly decreased under hypoxic treatment. Of the hypoxia-tolerant cuhivar Lubachun No. 4, the increase in LDH activity was less, the increase in ADH activity was higher, lactate content was lower and ethanol content was higher, and the decrease extent of SDH activity was lower compared to aired treatment in seedling roots than those of hypoxia-sensitive cuhivar Zhongnong No. 8, which played an important role in enhancing hypoxia resistance for cucumber seedlings. Under hypoxia stress, compared with single hypoxie treatment, TFP treatment decreased the content of Put and the activities of SDH and ADH, but increased the contents of Spd, Spm and lactate, and LDH activity, which inhibited the growth of roots. The damage of Lubachun No. 4 seedling roots was severer than that of Zhongnong No. 8 under TFP treatment. It indicated that Ca^2+ and CaM might be involved in the regulation of polyamine contents and respiratory metabolism in cucumber seedling roots, and the restriction of the function of Ca^2+·CaM could reduce the hypoxia tolerance of cucumber seedlings. Tab 5, Ref 25