不同光环境中氮素对烤烟质体色素降解产物及品质的影响

以烤烟品种豫烟5号为材料，采用4种光照强(L0:950-1125 μmol m–2 s–1，L1:770-900 μmol m–2 s–1，L2:610-720 μmol m–2 s–1，L3:475-565 μmol m–2 s–1)度和3种氮素水平(N1:1.5 g pot–1，N2:3.5 g pot–1，N3:5.5 g pot–1)的复因子盆栽试验，分析了不同光氮水平对烤烟质体色素降解产物、有机酸及碳氮代谢产物的调控效应。结果表明:随光强降低和氮素水平升高，质体色素(chla、chlb、chla+b、car)和新植二烯含量升高，两者存在显著正相关性；类胡萝卜素降解产物含量在适度弱光(L2)下最高，自然光强下中、低氮处理有利于其形成和积累，弱光条件下高氮处理含量较高；随光强减弱，多元羧酸总量升高，不饱和脂肪酸总量降低；遮阴条件下增施氮肥促使有机酸含量增加，饱和脂肪酸含量在高氮水平下最高；随施氮量增加及光强减弱含氮化合物含量上升，碳水化合物含量下降，烟株氮代谢强于碳代谢。叶绿素降解产物与碳水化合物间的正相关性最显著，类胡萝卜素降解产物与含氮化合物间存在显著指数正相关关系。弱光环境中通过控制氮素用量调控质体色素含量是提高烟叶品质和香气质量的有效途径。 

Effects of nitrogen supply on the degradation products of plastid pigment and the quality of flue-cured tobacco under different light conditions

The effects of light intensity and nitrogen on degradation products of plastid pigment, organic acids components and the substances in carbon-nitrogen metabolism have been analyzed in this study. Flue-cured tobacco cultivar Yuyan 5 was used in a pot-culture experiment, with the treatments of light intensity (four levels: L0: 950-1125 μmol m–2 s–1, L1: 770-900 μmol m–2 s–1, L2: 610-720 μmol m–2 s–1, L3: 475-565 μmol m–2 s–1) and nitrogen supply (three treatments: N1: 1.5 g pot–1, N2: 3.5 g pot–1, N3: 5.5 g pot–1), the results indicated that with the application of nitrogen the content of neophytadiene and plastid pigments which included chlorophyll a, chlorophyll b, total chlorophyll and carotenoid was significantly increased under shading, in the meantime, there was a significant positive correlation between the plastid pigments and neophytadiene. Compared to high-nitrogen treatments which could promote the formation of carotenoid degradation products under low light intensity, the condition of mid-nitrogen and low-nitrogen levels facilitate the accumulation of carotenoid degradation products under natural light intensity. The content of carotenoid degradation products reached highest at 70% Light intensity(L2). The total content of multiple carboxylic acids was increased but the content of un-saturation fatty acid was decreased when light intensity decreased. Nitrogen application could improve the amount of organic acids under shading and the total content of saturation fatty acid reached the highest at high-nitrogen levels. The results also showed that the contents of nitric compounds increased with increasing the rate of shading and nitrogen, however, the content of carbohydrate reduced. Generally, the nitrogen metabolism was likely stronger than the carbon metabolism. The regression analysis showed that the positive correlation relationship between the products of chlorophyll degradation and carbohydrate content reached most significant levels. There was a significant positive exponential relationship between the carotenoid degradation product and nitric compounds. The proper application of nitrogen could regulate the plastid pigment components and improve the quality of scent in flue-cured tobacco under low light intensity.