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亚热带常绿阔叶林荷树-厚壳桂群落的碳、氮及水分状况的垂直分布

THE VERTICAL PROFILES OF CARBON, NITROGEN AND WATER CONDITION IN SCHIMA SUPERBA-CRYPTOCARYA CHINENSIS COMMUNITY OF SUBTROPICAL MOSOONAL FOREST

  • 摘要: 亚热带常绿阔叶林荷树-厚壳桂群落乔木层植物叶片的单位面积干重较灌木层植物高。群落植物叶氮含量多为12-20mg/g干重,叶磷含量以0.4-1.0mg/g干重占叶的比例最大。叶氮(单位面积含量)和叶磷(单位干重含量)随群落垂直高度增高而增大。叶片叶绿素含量和光合速率亦随垂直增高而增大。群落乔木层植物较灌木层植物有较低的叶片水势。群落乔木层植物较高的碳氮投资和较高的光合速率,构成群落生产力的主要部分。这种群落结构有利于光及其它资源利用,以达到高的生物效益。

     

    Abstract: In Schima superba-Cryptocarya chinensis Community, greater weight per leaf(one side)and more number of stomata were found in tree layer comparied with that of understories. For most plants in this community, their leaf nitrogen is 12—20 Nmg/g DW, leaf phosprous is 0.4—1.0 Pmg/g DW. As the hight increases in vertical profile, nitrogen and phosprous content increase. Chlorophyll content and photosynthetic rate incease as the hight above forest floor increases. The results might show that more investments of carbon and nitrogen in leaves of tree layer were made for increasing photosynthetic income.Leaf water potential decreases during 7 a. m.—11 a.m., it drops to the lowest point at 15 p. m. The leaf water potential in leaves of tree layer is lower than that of understories. But leaves of tree layer have higher leaf cond-uctance.

     

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