密植板栗树净光合作用生理生态的初步研究

A PRELIMINARY STUDY ON THE ECOPHYSIOLOGICAL CHARACTERISTIC OF PHOTOSYNTHESIS OF CHESTNUT IN HIGH DENSITY PLANTING ORCHARDS

对８年生密植板栗园“九家种”品种叶片净光合速率及其与生理、生态因子的相关关系进行了系统研究。结果表明：（１）板栗净光合速率（Ｐｎ）一般为４～２０ｍｇ·ｄｍ－２·ｈ－１明显低于苹果、梨等果树；（２）Ｐｎ的日变化规律在生长初期和生长末期为单峰曲线，而在生长盛期（６～８月）为双峰曲线；（３）Ｐｎ的年变化进程也表现为双峰曲线，其高峰分别出现在开花期及果实速生期，Ｐｎ的年变化规律与叶绿素含量、矿质元素（Ｎ、Ｋ）含量的年变化趋势相一致，而与蒸腾强度的关系则较复杂；（４）叶片Ｐｎ直接受光合有效辐射（ＰＡＲ）的制约，同时还受气温和空气相对湿度的影响。

The photosynthetic characteristic and its relation to ecophysiological factors in a eight year old chestnut ( Castanea mollissim) in high density (2m×3m) orchards were studied. The main results were as follows: 1. The net photosynthetic rate (Pn) was generally 4～10 mg. CO 2. dm -2 ·h -1 ,which was obviously lower than the other fruit trees such as apple, pear etc.; 2. The changes of Pn in a day time showed a singe peak curve during the early and later growth stages, but it was a double peak curve during rapid growth stages (6～8 months); 3. The seasonal changes in Pn also showed a double peak curve, the two peaks occurred during the flowering stage and fruit fast growth stage, respectively. The seasonal changes in Pn showed to be closely related to the seasonal variations of chlorophyll, water and mineral elements (N,P,K)contents in leaves, but were not well related to the transpiration rate; 4. The Pn was affected by temperature and relative humidity of ari as well as directly constrained by intensity of photosynthetically active radiation(PAR).