长期增施CO_2条件下黄瓜叶片淀粉积累对光合作用的影响

Effects of the Starch Accumulation on Photosynthesis of Cucumber Leaves Under Long Term Elevated CO_2 Condition

以日光温室栽培的‘津优35号’黄瓜作为试验材料,探究了在长期增施CO2的条件下黄瓜叶片淀粉含量与光合作用的变化关系。研究结果表明：①单纯的高温处理（40~45℃）会抑制黄瓜叶片的光合作用,净光合速率低于对照常温处理以及高温＋CO2和常温＋CO2两个处理,而且在处理22 d时就已经达到最大值,光合产物——淀粉的合成也最少,其分解成的可溶性糖也最少。②增施CO2可以提高黄瓜叶片的光合速率,而且高温＋CO2处理〉常温＋CO2处理;高温＋CO2处理在处理36 d时净光合速率达到最大值后下降;常温＋CO2处理在处理29 d时达到最大值后下降。③黄瓜叶片内淀粉含量的变化为先降低再升高的趋势,可溶性糖含量则呈现出与淀粉含量相反的变化趋势。高温＋CO2处理淀粉含量在处理第36 d以后开始高于对照,随着时间处理的延长,淀粉含量逐渐增加,转化成的可溶性糖含量开始下降;常温＋CO2处理22 d以后淀粉就开始积累,而在处理36 d时其净光合速率就已经低于对照,淀粉的积累对光合作用造成了反馈抑制。

In this experiment,Jinyou 37 was selected as the material to study the relationship between photosynthesis and starch content of grafted cucumber in greenhouse at elevated CO2 conditions. The results showed that：① High temperature treatment inhibited the net photosynthesis rate of cucumber leaves and reached at the peak level after treatment of 22 days,content of starch and carbohydrate was the lowest of the treatments. ②The photosynthesis could be promoted with elevated CO2. It reached at the peak level after 29 days of treatment with elevated CO2 at ambient temperature,while treatment with elevated CO2 at high temperature extent to 36 days. ③Content of carbohydrate presented the opposite changes with starch content. Starch content was higher than control after treatment of 36 days with elevated CO2 at high temperature condition;Content of starch with elevated CO2 at ambient temperature started to increase after treatment of 22 days,of which was earlier than the other treatments in terms of the starting time of the starch accumulation,but its net photosynthesis was lower than control after treatment of 36 days,starch content t had significant negative correlation relationship with the net photosynthetic rate,which turned out that the accumulation of starch made a feedback to photosynthesis in cucumber leaves.