2种不同树龄磨盘柿树光合作用日变化的初步研究

Preliminary Study on Diurnal Variations of Photosynthesis of Mopan Persimmon Trees with Different Tree Age

对2种不同树龄、不同挂果量的磨盘树进行了光合作用日变化的初步比较研究,旨在为磨盘柿无公害标准化栽培管理提供相关科学依据。结果表明不同树龄的磨盘柿,其净光合速率日变化曲线均为双峰型,一天中最高值出现在10:00前后,次高峰出现在16:00左右;而光合午休持续的时间不同,15年生柿树光合速率在13:00左右到达谷值后上升,而8年生柿树的光合午休提前和延长了1h,即从12:00持续到14:00。不同树龄的磨盘柿树蒸腾速率日变化曲线基本上为单峰型,峰值均出现在14:00左右;同时通过方差分析显示,在大多数测定时刻中,15年生柿树的净光合速率明显高于8年生柿树。结果还表明,地面覆盖生草有利于减轻磨盘柿树光合午休发生程度。

To provide a technical basis for standard cultivation of non-polluted Mopan Persimmon, diurnal variations of photosynthesis of Mopan Persimmon trees with different tree age and fruit setting were studied in this article. The results showed that the diurnal courses of net photosynthetic rate （P n） of 8- or 15-year old Mopan Persimmon trees both were double-peaked curves with the highest value reached at 10：00 and the second value occurred at 16：00, but the sustained time of midday depression of photosynthesis was different. For the 15-year old Mopan Persimmon trees, the midday depression of photosynthesis occurred at about 13：00 then theP n increased, but for the 8-year old trees, the sustained time of midday depression of photosynthesis occurred from12：00 to 14：00. The diurnal course of transpiration rate（T r）of Mopan Persimmon trees were single-peaked curve with the highest value reached at 14：00. The variance analysis results showed that theP n of 15-year old trees was significant higher than that of 8-year old trees at most moment measured. The results also showed that ground coverings attributed to alleviate the midday depression of photosynthesis of Mopan Persimmon trees.