烤烟成熟期控水对烟叶主要碳氮化合物含量的影响

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主要碳氮化合物的影响，试验在烤烟成熟期进行土壤控水，研究烟叶总糖、还原糖、淀粉、总氮和烟碱等的变化。结果表明：土壤含水率70%~85%，烤烟生长后期（移栽后约83天）烟叶总糖、还原糖和淀粉含量较高；干旱胁迫降低碳代谢，而干旱后复水碳代谢增强。70%~85%土壤含水率，烤烟总氮和烟碱水平较低；干旱胁迫促进氮代谢，总氮和烟碱含量较高；干旱胁迫后复水，烟叶总氮和烟碱含量处于中等水平。烤烟成熟期，土壤水分过高或过低，均不利于协调烟叶碳氮代谢平衡。

Effect of Different Soil Moisture Regimes at the Maturity Stage on Content of Carbonand Nitrogen Compounds 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 content of total sugar, reducing sugar, starch, total nitrogen and alkaloid in flue-cured tobacco in field. The results showed that: with soil moisture content of 70% to 85%, the flue-cured tobacco had high contents of tobacco total sugar, reducing sugar and starch at the late growing stage (after transplanting approximately 83 d); drought stress decreased carbon metabolism, however, after the drought re-watering enhanced carbon metabolism. When soil moisture content of 70% to 85%, total nitrogen and nicotine levels was lower; drought stress promoted nitrogen metabolism, and total nitrogen and nicotine content was increased; while re-watering after drought stress, contents of tobacco leaf nitrogen and nicotine was in the middle level. At the maturity stage of tobacco, soil moisture was too high or too low, not to facilitate the coordination of the balance between tobacco leaf carbon and nitrogen metabolism.