[目的]研究不同海拔下烤烟(Nicotiana glauca L.)叶片化学成分的代谢规律,探讨不同海拔下烤烟生长过程中内部生理变化.[方法]试验地选取在毕节市3个高、中、低海拔的典型烟叶产区,其中金沙县西洛乡为低海拔(840 m),大方县双山镇为中海拔(1 430m),威宁县牛棚镇为高海拔(2 100 m).单因子随机区组设计,重复3次.[结果]在移栽后50～95 d,不同海拔烤烟叶片化学成分代谢规律不完全相同.其中,低海拔下烟叶的叶绿素a、叶绿素b、紫黄质、叶黄素、β-胡萝卜素、氨基酸含量和糖碱比呈线性下降趋势；中海拔下烟叶氨基酸含量呈线性下降趋势,而糖碱比及叶绿素a、叶绿素b、紫黄质、叶黄素、β-胡萝卜素含量先升高后降低；高海拔下烟叶糖碱比及叶黄素、β-胡萝卜素含量呈线性下降趋势,而叶绿素a、叶绿素b、紫黄质含量先升高后降低,氨基酸含量呈先降低后升高而后又降低的趋势.在移栽后95 d,烟叶叶绿素a、叶绿素b、类胡萝卜素、氨基酸含量与海拔呈正相关；还原糖含量、糖碱比与海拔呈负相关；淀粉和烟碱含量在低海拔下最适中,在高海拔、中海拔下表现为过高或过低.不同海拔下烤烟叶片新黄质、还原糖和烟碱含量的变化规律一致,其中新黄质含量先升高后降低,还原糖含量呈线性下降趋势,烟碱含量趋于稳步上升,但淀粉含量变化规律不同.[结论]该研究可为毕节市不同海拔生态区域特色烟叶质量的形成提供参考.%[Objective]The purpose was to study the effects of suboptimal temperature and photo flux density treatment on growth, photosynthetic characteristics and nitrogen content of cucumber seedlings, and discuss its effects mechanism on growth and photosynthetic apparatus of cucumber and plants'adaptive mechanism to adversity of suboptimal temperature and photo flux density.[Method]The suboptimal temperature and photo flux density was 18/12 ? and (200 ?0) 祅ol/(m ?s) respectively, and cucumber seedlings were treated in 5 and 10 days under this condition.[Result]The results showed that growth of cucumber seedlings were significantly inhibited, and the biomass accumulation and leaf nitrogen content were re duced by suboptimal temperature and photo flux density stress, but no influence on nitrogen content in cucumber roots; the content of chlorophyll a and b were increased after 5 d stress and then decreased for 10 d stress. The decline of net photosynthesis of cucumber seedlings under suboptimal temperature and PFD stress for 5 d were caused primarily by stomatal limitation, and the decline for 10 d were caused mainly by non-stomatal limita tion.[Conclusion]The study provides a theoretical basis for finding out effective measures on controlling suboptimal temperature and photo flux den sity environment to guide greenhouse cucumber production in winter and spring.
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