增强的UV—B辐射对麦田生态系统Mg和Zn累积和循环的影响

近 2 0多年以来 ,ＵＶ Ｂ辐射增加对植物个体的影响受到了广泛的关注 ,而对植物群体和生态系统的影响仍然知道的很少2 ] 。仅见ＵＶ Ｂ辐射对副极地石南灌丛和沙丘草地生态系统物种结构、生长、物候和叶分解等方面有报道3,4 ] 。ＵＶ Ｂ辐射影响植物Ｍｇ和Ｚｎ吸收和运转5～ 7] ,但对营养累积和物质循环的影响了解甚少3] 。因此 ,大田条件下 ,植物群体和生态系统水平的营养累积和物质循环对ＵＶ Ｂ辐射的响应与反馈的研究 ,对于真实评估ＵＶ Ｂ辐射对生态系统的影响是必不可少的2 ] 。ＵＶ Ｂ辐射对春小麦生长、生理、群体结构、植物营…

Effects of Enhanced UV-B Radiation on Accumulation and Cycling of Mg and Zn of Wheat Field Ecosystem.

Influences of enhanced ultraviolet radiation (UV B,280-315nm) on accumulation and cycling of Mg and Zn of wheat field ecosystem were investigated under field conditions.UV B radiation increased concentrations of Mg and Zn in leaves and stems,and affected concentrations of Mg and Zn in roots and spikes at various developmental stages significantly.The responses of accumulation of Mg and Zn in leaves to UV B radiation were different among developmental stages.Accumulation of Zn in stems were higher than control under 2.54 and 4.25 kJ.m -2 UV B radiation,and lower than control under 5.31 kJ.m -2 UV B radiation.At various developmental stages,UV B radiation significantly reduced accumulation of Mg in stems,roots and spikes,and accumulation of Zn in roots and spikes.UV B radiation significantly decreased accumulation of Mg and Zn in whole plants at various developmental stages.The contribution of biomass to the accumulation of Mg and Zn might be more than that of the concentrations of Mg and Zn.UV B radiation reduced output of Mg and Zn of spring wheat colonies.This might indicate decreases in output input ratio and cycling function of Mg and Zn in wheat field ecosystem.Increases in concentrations of exchangeable Mg and available Zn in soil were the results of decreases in output of Mg and Zn of spring wheat colonies. It might lead to the occurrence of higher storage of Mg and Zn in soil.