摘要
以上海市杨浦区原废弃地(新江湾地区)半自然群落的主要优势树种为对象,测定不同生活型植株在夏季不同生境下叶片的光合特性,从光合生理生态角度分析低干扰条件下上海城市废弃地的植物群落次生演替过程的特点,并结合环境因子分析并预测植物群落结构的动态变化。结果表明:(1)冠层树种光合作用日变化曲线呈双峰型,林窗树种呈单峰型,而林下树种呈不规则变化,体现出亚热带地区植物在夏季典型气候下的"光合午休"现象,而生境特点同时也影响植物光利用对策。(2)冠层成年树以落叶树种刺槐和朴树的日均净光合速率最高,且具有较高的光饱和点;在林下生境中,以强耐阴灌木植物胡颓子的日均净光合速率最高,其次为常绿树种香樟和女贞的幼树和幼苗,而林下落叶树种日均净光合速率均较低。(3)影响冠层树种的净光合速率因子中,生态因子是第一主成分,而对于林窗树种,第一主成分则是生理因子。(4)由于阳性落叶树种具有更高效的光合效率,能迅速占领上层空间,新江湾区域人为低干扰植物群落的演替早期均以扩散能力较强的先锋性树种为主;乔木群落形成后,林下更新苗则以光适应范围较宽的香樟、女贞为主,同时,上层落叶树种大规模自然衰退使得香樟和女贞逐步替代落叶树种。
The photosynthetic characteristics of different life forms of mainly dominant species under different habitats during summer were studied in New Jiangwan Conservation which is located in Yangpu district of Shanghai.The process and characteristic of plant community in urban abandoned district were analyzed from the view of photosynthetic ecology.Meanwhile,the dynamic changes of plant community structure were forecasted with the analysis of the mainly environmental factors.The results shows that：（1）Diurnal changes of photosynthesis in canopy species was showing bimodal curves,species in forest gap bell-shape curves,and understory species irregular curves.This indicated the midday depression of photosynthesis of subtropical trees under typical climate in summer.The habitat characteristics also influenced the photosynthetic capacity.（2）The daily average net photosynthetic rates of deciduous trees,such as Robinia pseudoacacia and Celtis sinensis were higher than that of other adult trees in canopy.And deciduous trees had higher light saturation point.Elaeagnus pungens,one of the shade-tolerant shrubs had the highest daily average net photosynthetic rate in understory,next were the young trees and seedlings of Cinnamomum camphora and Ligustrum lucidum,while deciduous trees in understory had low daily average net photosynthetic rate.（3）Based on principal component analysis between net photosynthesis and physio-ecological factors,in canopy the first principal component was ecological factors,while in gap the first principal component was physiological factors.High photosynthetic efficiency of deciduous trees made them rapidly occupy the upper space.Pioneer tree species with high dispersal ability dominated in early succession stage in new Jiangwan conservation.When the tree community formed,understory seedlings were mainly the species such as C.camphora and L.lucidum with wide range of light adaption.Upper deciduous trees large-scale decline makes C.camphora and L.lucidum gradually replace deciduous trees.
出处
《西北植物学报》
CAS
CSCD
北大核心
2012年第9期1850-1857,共8页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家十二五科技支撑计划(2011BAD38B03)
沪农科攻字[(2009)第9-6号]
沪农科攻字[(2008)第10-3号]
关键词
半自然群落
净光合速率
光合生理生态
演替
semi-natural plant community
net photosynthetic rate photosynthetic eco-physiology
succes-sion
