氮素营养对烤烟叶片淀粉积累及SPS、淀粉酶活性的影响

在大田条件下研究了烤烟红花大金元(HD)和K 326叶片淀粉积累动态,分析比较了不同施氮量和氮素形态对叶片淀粉含量和蔗糖磷酸酯合成酶(SPS)、淀粉酶活性的影响.烟株生长进入成熟期后,叶片开始快速积累淀粉,接近成熟时达到最高;中部叶片淀粉含量HD为40%左右、K 326为25%左右.成熟期叶片淀粉含量、SPS活性与施氮量呈负相关,HD淀粉酶活性随施氮量增加呈下降趋势,K326淀粉酶活性与施氮量的关系在刚封项后为负相关,叶片接近成熟时为正相关.施氮不足或过量会增加原烟淀粉含量.氮素形态对HD淀粉代谢的影响不如K 326明显;在N-NH4+N-NO3-为11时,K 326淀粉含量、SPS和淀粉酶活性较低.

Effect of Nitrogen Nutrition on Starch Accumulation and Activity of SPS and Diastase in Tobacco Leaves

The accumulation dynamics of starch in two tobacco cultivars (K 326 and HD) were studied under field conditions. The effect of levels and forms of nitrogen applied on starch content, activity of SPS and diastase in tobacco leaves were also analyzed. The amounts of starch accumulation in tobacco leaves increased rapidly during the ripening process, and reached maximum in tobacco maturation, about 40% for HD and 25% for K 326 in cutters, respectively. Starch content and SPS activity in tobacco leaves was negatively related to the levels of nitrogen applied, diastase activity in HD decreased with increasing nitrogen applied during the ripening period, and the correlation between starch content in K 326 and nitrogen levels applied was negative just after topping and was positive in maturation. Either less or extra levels of nitrogen applied led to a high content of starch in cured tobacco. Forms of nitrogen influenced metabolism of starch in K 326 more significantly than that in HD. Content of starch, activity of SPS and diastase in K 326 kept a low level with 1:1 of N-NH\ \-4:N-NO\ -\-3.