浙江天台山七子花等6种阔叶树光合生态特性

PHOTO-ECOLOGICAL CHARACTERISTICS OF SIX BROAD-LEAVED SPECIES INCLUDING HEPTACODIUM MICONIOIDES IN THE TIANTAI MOUNTAINS IN ZHEJIANG PROVINCE

对分布在浙江天台山的七子花 (Heptacodiummiconioides)等 6种主要阔叶树的光合生理生态特性进行了研究 ,结果表明 :1)夏季 6种植物光合日进程均为“双峰”型 ,有明显的光合“午休”现象。日均净光合速率月变化呈“单峰”型 ,8月是一年的高峰期。日均和 5～ 11月平均净光合速率最高的是东南石栎 (Lithocarpusharlandii) ,最低的是天台阔叶槭 (Aceramplumvar.tientaiense) ,七子花处于中下水平。 2 )相对常绿树种而言 ,七子花的光补偿点较高 ,光饱和点较低 ,对光适应的生态幅度较窄。 3)叶绿素含量最高的是东南石栎 ,最低的是甜槠 (Castanopsiseyrei) ,不同种类植物叶绿素含量与净光合速率大小不存在必然的联系 ,同种植物叶绿素含量的季节变化与其净光合速率、光饱和点呈正相关 ,与光补偿点呈负相关。 4)硝酸还原酶活力较大的植物 ,其净光合速率也较大 ,硝酸还原酶活力的季节变化与净光合速率具有一定的相关性。

The photo-ecological characteristics of the six major broad-leaved species, including Heptacodium miconioides, in the Tiantai Mountains of Zhejiang Province were researched. In summer the diurnal variations of net photosynthetic rates (P n) of the six species are all 'twin-peaked', with obvious 'midday-depression' of photosynthesis. Their monthly variations of diurnal average P n are 'single-peaked', with maximum values in August. From May to November, the average diurnal P n and monthly P n in Lithocarpus harlandii are highest, those in Acer amplum var. tientaiense are lowest, and those in H. miconioides are below average. Compared with evergreen species, the light compensation points (LCP) of H. miconioides are high, its light saturation points (LSP) are low, and its ecological ranges of light adaptability are narrow. The chlorophyll contents in L. harlandii are highest, and those in Castanopsis eyrei are lowest. There are no inevitable connections between chlorophyll contents and P n among different species. The monthly variations of chlorophyll contents in leaves of the same species are positively related to P n and LSP, but negatively related to LCP. In those species with high nitrate reductase activity, the P ns are high too. There is a correlation between the monthly variations of nitrate reductive activity and P n.