番茄叶片糖与转化酶的日变化研究

为探讨转化酶在叶片糖分含量和光合作用日变化中的作用,测定了番茄(Lycopersicon esculentumL.)叶片光合速率、转化酶活性、淀粉、蔗糖、葡萄糖和果糖含量,并分别分析了12:00前后它们间的相关关系.结果表明:番茄日间叶片净光合速率在10:00和16:00出现一大一小两个高峰;6:00~18:00叶片中淀粉和果糖呈现持续升高,而蔗糖和葡萄糖为先升后降趋势;光合速率同叶片蔗糖含量和胞质转化酶活性存在高度正相关,淀粉和果糖含量同光合速率未表现出显著相关性.由此可知,胞质转化酶在蔗糖代谢方面有明显的作用;果糖可能是通过抑制胞壁转化酶活性,促进了蔗糖外运.

Diurnal Variation of Invertase Activities and Sugar Content in Tomato Leaves

The diurnal variations of photosynthetic rate,invertase activities and sugar content in tomato leaves were measured from 6:00 to 18:00.The results showed:there were two net photosynthetic rate high points at 10:00 and 16:00,and starch and fructose content kept increasing,however,sucrose and glucose content decreased after 12:00.There were high correlation between photosynthetic rate,sugar content and cytosolic invertase activity;Photosynthetic rate wasn't significant negative correlated with starch and fructose content in leaves.Cytosolic invertase would play a key role in avoiding superfluous sucrose accumulation in cytoplasm to inhibit photosynthetic rate.Fructose of high concentration might restrain the activity of cell wall invertase,and facilitate sucrose transiting out.