摘要
从影响植物N素吸收的因素来看,大气CO2体积分数升高条件下植物净光合作用增强,碳同化产物增多,利于改善N素吸收的能量和物质基础;植物根系生长增强,生物量增多且空间分布加大,有利于N素吸收;但土壤有效N供应能力的变化存在增强和减弱两种观点。从植物N素吸收的实际情况来看,大气CO2体积分数升高条件下植物N吸收总量并未增加,植物体内N质量分数普遍降低,某些种类植物N吸收形态也发生了改变。因此要阐明大气CO2体积分数升高对植物N素吸收的影响机制,必须探明土壤有效N供应能力的变化:CO2体积分数升高条件下N矿化作用是否增强,微生物和植物间是否存在对有效N的竞争,此外,CO2体积分数升高条件下植物根系形态特征变化和N素吸收(包括主动和被动吸收)的生理机制及其与环境因素的关系也值得进一步研究。
In this paper, the effect of elevated atmospheric CO2 on plant nitrogen uptake was briefly reviewed. Carbohydrate accu-mulation in plant tissues as the result of stimulated photosynthesis under elevated CO2 might favor plant N uptake; elevated atmos-pheric CO2 also increased biomass and volume of the root system, thus allowing a greater exploitation of available N; but the effect of elevated atmospheric CO2 on soil N availability is still in dispute by now. However, plants did not always uptake more nitrogen and tissue N concentrations were decreased due to elevated atmospheric CO2. And elevated atmospheric CO2 also had influence on the form of N uptaken by some plant species. Thus, the effect of elevated CO2 on soil N availability, or in other words, changed N mineralization and the possible compitition for available N between soil microbial and plants could have major implications in plant N uptake. Besides, further research on physiological mechanism of altered root morphological characteristics and root N uptake are necessary.
出处
《生态环境》
CSCD
北大核心
2005年第3期429-433,共5页
Ecology and Environmnet
基金
国家自然科学基金项目(NSFC-40271061)
国家自然科学基金重大国际合作研究项目(NSFC-40120140817)
中国科学院知识创新重要方向项目(KZCX2-408)
国家973项目(CCDMCTE-2002CB412502
2002CB714003)
