烤烟成熟期控水对烟叶碳氮代谢关键酶活的影响?

成熟期是烤烟需水次临界期。为明确烤烟成熟期土壤水分对烟叶碳氮代谢的影响，试验在烤烟成熟期进行土壤控水，研究烟叶碳氮代谢主要关键酶活性的变化。结果表明：土壤水分亏缺（50%~60%田间持水量）致烟叶叶绿素含量降低，土壤水分充足（80%~85%田间持水量）烟叶绿素含量高，烟叶成熟缓慢，且复水能缓解干旱胁迫导致的烟叶早衰；烟叶成熟期，湿润土壤（70%~85%田间持水量）烟叶硝酸还原酶、转化酶和淀粉酶活性较高，土壤干旱使烟叶碳氮代谢关键酶活性减弱，但复水在一定程度上能恢复淀粉酶活性。

Effect of Different Soil Moisture Regimes on Enzyme Activities of Carbon and Nitrogen Metabolism at the Maturity Stage in Flue-cured Tobacco

Maturity stage is subcritical period of water demand for flue-cured tobacco. This study was to demonstrate effect of different soil moisture regimes at the maturity stage on enzyme activities of carbon and nitrogen metabolism in flue-cured tobacco in field. The results showed that: soil water deficit (50%-60% maximum field capacity) would decrease the chlorophyll content of tobacco leaves; chlorophyll content of tobacco leaves was higher when soil moisture was adequate (80%-85% maximum field capacity), however, tobacco leaves slowly matured; re-watering faded away premature of tobacco leaves by drought stress. Activities of nitrate reductase, invertase and amylase were higher in moister soil than in droughty soil; nonetheless, amylase would increase when re-watering, to some degree.