光照条件对浙江楠幼苗生长及光合特性的影响

Effects of Light Condition on the Growth and Photosynthetic Characters of Phoebe chekiangensis Seedings

以珍稀树种浙江楠为研究对象,对不同光照条件下浙江楠幼苗的生长及某些生理特性进行了研究。结果表明:(1)光照条件对苗木单株分枝数目、叶片数目和冠幅均有极显著影响,遮荫条件下苗木单株分枝数目、叶片数目和冠幅均有所下降;(2)遮荫条件下,浙江楠单叶面积变化不大,但是单叶干重变化较为明显,比叶面积增大,但比叶重减少,表现为低的光合能力;全光条件下,单叶干重最大,表明叶片内部干物质积累多;(3)遮荫条件下叶绿素a、叶绿素b、叶绿素总量均表现为增加,有利于在弱光下提高苗木光合能力;(4)全光和弱度遮荫条件下,苗木具有较大的净光合作用速率,苗木生长旺盛,碳水化合物的积累较多,生物量增加。重度遮荫时,苗木具有较小的净光合作用速率,碳水化合物的积累较少,生长缓慢,生物量下降。

The growth and certain physiological characters of Phoebe chekiangensis Shang seedlings under various light intensity conditions were studied in this thesis.The results indicated that:(1)The effects of light on ramellus number,leaf number and crown-area per seedling were obvious,them all went down under various shading;(2)The variation of leaf area per seedling was slight,but the variation of leaf dried mass per seedling was evident.In the full light,the leaf dried mass per seedling was the heaviest,this indicated that the dried material accumulated was the most.On the other hand,leaf area per unit dried mass(L_(AM)) per unit area increaseed,but leaf dried mass per unit area (L_(MA)) decreased under shading,so photosynthesis ability(Pa) decreased;(3)All the content of chlorophyll a,chlorophyll b and chlorophyll a+b increased under shading,this were advantageous to the improvement of Pa under shading; (4)The net photosynthetic rate(Pn) was higher under full-light and slight shading,growing seedlings was vigorous,the accumulation of CH_2O was more,and biomasses increased obviously.Under strong shading the of seedlings was low,the accumulation of CH_2O was few,and seedlings growed slowly.