摘要
对分布在浙江天台山的七子花群落主要植物种类的光合生理生态特性进行了研究。结果表明 :夏季 ,位于群落冠层上层、林窗、林缘的七子花及主要伴生植物叶片的光合日进程均呈“双峰”曲线 ,有明显的光合“午休”现象。而位于冠层中、下层以及林下的七子花、草本植物 ,其光合日进程曲线平缓。从冠层上层到下层 ,七子花叶片的日均净光合速率 ( Pn)呈下降趋势。林窗、林缘的七子花小树叶片日均 Pn比林下大 ,冠层上层的七子花中树叶片与林窗、林缘的小树叶片日均Pn差异不显著。七子花在不同生境中与伴生植物相比 ,日均 Pn较低 ,光合能力较弱。同一植株七子花冠层上层叶片叶绿素含量最低 ,下层次之 ,中层最高。阴生草本植物在弱光下仍有很高的叶绿素含量。植物叶片的光合能力大小与叶绿素含量高低不呈正相关。相对常绿树种而言 ,七子花光补偿点较高、光饱和点较低 。
In the last tenday period of July 2001, by using the Leaf Chamber Analyzer (type LCA-4) manufactured by ADC Bioscientific Ltd. in England, we studied the photosynthetic characteristics of the main accompanying species of Heptacodium miconioides community in Tiantai Mountain in Zhejiang Province. Their chlorophyll content, light compensation points (LCP) and light saturation points (LSP) were also ascertained by measuring. The results are as follows: In summer, the curves of the diurnal photosynthetic variations in the leaves of Heptacodium miconiodes, which is in the upper layer of the canopy, as well as those in its main accompanying species such as Lithocarpus harlandii, Rhododendron fortunei, Quercus glandulifera var. brevipetiolata and Fraxinus insularis, are of the double-peak type, and show obvious “midday- depression” of the net photosynthetic rate (P n). The curves of the diurnal photosynthetic variations in the leaves of Heptacodium miconioides saplings, which are in the canopy gap or the forest edge, as well as those of shrub species in the canopy gap such as Lindera relexa and Camellia cuspidated, are also of the double-peak type because of the high photosynthetic active radiation (PAR). The curves of the diurnal photosynthetic variations in the leaves of Heptacodium miconioides, which is in the middle or the lower layer of the canopy, as well as in Heptacodium miconioides, Aster ageratoides and Althyrium niponicum which are in the under-story, are quite level because of the low PAR, showing little difference between the peak and the bottom. The daily average P n in the leaves of the middle tree of Heptacodium miconioides in the upper layer of the canopy is higher than that in the middle or lower layer of the canopy, showing extremely conspicuous variation. The daily average P n in the leaves of Heptacodium miconioides saplings which are in the canopy gap and forest edge is higher than that of those in the under-story, showing extremely conspicuous variation. But the daily average P n in the leaves of Heptacodium miconioides in the canopy gap and that in the forest edge are relatively close to each other, showing little variation. The variances of daily average P n between the middle tree of Heptacodium miconioides in the upper layer of the canopy and the Heptacodium miconioides sapling in the canopy gap or the forest edge are not conspicuous. This shows that P n is little affected by the age of the tree but greatly affected by PAR. In the upper layer of the canopy, the daily average P n in the leaves of Heptacodium miconioides is lower than that in the leaves of evergreen species such as Lithocarpus harlandii and Rhododendron fortunei. The variances between Heptacodium miconioides and Lithocarpus harlandii are extremely conspicuous, and those between Heptacodium miconioides and Rhododendron fortunei are conspicuous. The variances of daily average P n are not conspicuous between Heptacodium miconioides and deciduous species such as Quercus glandulifera var. brevipetiolata and Fraxinus insularis. In the shrub layer, the daily average P n in the leaves of Heptacodium miconioides is lower than that in Lindera reflxa, with conspicuous variances; but the variances between Heptacodium miconioides and Camellia cuspidated are not conspicuous. In the under-story, the daily average P n of Heptacodium miconioides is lower than that of herb species such as Aster ageratoides and Althyrium niponicum, showing extremely conspicuous variation. In the various habitats, the daily average P n in the leaves of Heptacodium miconioides is of less value than that of its accompanying species. In the same Heptacodium miconioides tree, the chlorophyll content in the canopy leaves in the upper layer is lowest, that in the lower layer is second lowest, and that in the middle layer is highest. The variations among them are conspicuous or extremely conspicuous. The chlorophyll content of the middle layer and that of the lower layer is 63% and 20.7% higher than that in the upper layer respectively. The change
出处
《生态学报》
CAS
CSCD
北大核心
2002年第10期1645-1652,共8页
Acta Ecologica Sinica
基金
浙江省自然科学基金资助项目 ( 3992 0 3)
浙江省教育厅科研计划资助项目 ( 1 9990 36 7)
关键词
浙江天台山
七子花群落
植物种类
光合特性
Heptacodium miconioides community
main species
photosynthetic characteristics
tiantai mountain
