不同氮磷比与水分添加对刨花楠光合生理特性的影响分析

在全球变化的背景下,氮沉降现象普遍,降水分布不均,干旱变得更加频繁,植物对环境变化的响应与适应已成为亚热带地区研究的热点生态学课题之一。以亚热带珍贵常绿阔叶树种刨花楠(Machilus pauhoi)为对象,探讨不同氮磷比及水分添加对其光合生理特性各指标的影响。结果表明:(1)水分对刨花楠净光合速率(P_n)、光补偿点(LCP)、蒸腾速率(T_r)有显著影响,干旱胁迫下(田间持水量为40%)的刨花楠的P_n、LCP和T_r会明显下降,与正常水分条件(田间持水量80%)相比,P_n下降了52%,LCP下降了72%,T_r下降了38%;而水分对光饱和点(LSP)、气孔导度(G_s)、胞间CO_2浓度(Ci)、水分利用效率(WUE)无显著影响;(2)不同氮磷添加对P_n、LSP、LCP、G_s、C_i、WUE等光合生理特性指标无显著影响。

Effect of N/P Ratio and Water on Photosynthetic Physiological Characteristics of Machilus pauhoi

Under the background of global change,phenomenon of nitrogen deposition generally exists,with an uneven distribution of precipitation,and more and more frequent drought.Response and adaptation of plant to environmental change has become one of the hot ecological subjects in subtropical region.Taking an excellent subtropical evergreen broad-leaved tree species--Machilus pauhoi,as research object,the impact of different N:P ratios and water addition on indexes of photosynthetic physiological characteristics was discussed.Result indicates that: (1) Water have significant influences on net photosynthetic rate (Pn),light compensation point (LCP) and transpiration rate Tr of Machilus pauhoi.Under dry conditions (field capacity being 40%),Pn,LCP & transpiration rate (Tr) reduce sharply.Compared with normal water conditions (field capacity being 80%),Pn,LCP & Tr decrease 52%,72% & 38%,respectively.But water have no obvious effects on light saturation point (LSP),stomatal conductance (Gs),intercellular CO2 concentration (Ci) & water use efficiency (WUE);(2)Different nitrogen & phosphorus addition have no obvious effects on Pn,LSP,LCP,Gs,Ci & WUE.