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作 者 ：孙谷畴

期 刊 ：武汉植物学研究 1990年 8卷 3期 页码：254-260

关键词：Piperhispidum；Psychotriarubra光合速率(PN)；叶片水势(ψ)；叶片/空气水蒸汽压陡度(△W)；水；

Keywords:Piperhispidum, Psychotriarubra, Photosynthesis(PN), Leafwaterpotential(ψ), Leaf/airwatervaporgradient(△w), Wateruseefficiency(WUE),

摘 要 ：生长在热带植物温室的热带雨林植物Piper hispidum和亚热带季风常绿阔叶林植物九节(Psychotria rubra),在灌水、环境的CO₂浓度和26℃下,饱和光强的最大光合速率(PN)分别为6.3和9.8μmol·m^-2·s^-1.在低的叶片/空气水蒸汽压陡度(△w=10毫巴·巴^-1)情况下,每降低叶片水势(ψ)1巴,P.hispidum的PN降低0.38μmol·m^-2·s^-1;当ψ为-8巴时,PN随△w增高而降低,其关系PN=7.02-0.06△w(r²=0.7);ψ为—13巴时,PN与△w关系的直线斜率变小(0.02).对于九节,PN对△w变化的反应更为敏感.在ψ为-8.75巴时,PN=11.16—0.1△w(r²=0.65).在高ψ(-8和-8.75巴)情况下,两种灌木的气孔传导率(g)随△w的变化而相近;但ψ降低时,九节的g对△w的变化反应较P.hispidum敏感.ψ降低导致两种灌木的水分利用效率(WUE,μmol·m^-2·s^-1CO₂同化/mmol·m^-2·s^-1水散失)增高;而△w增高,WUE降低.九节的PN对△w增高的反应较P.hispidum敏感.

Abstract:Piper hispidum and Psychotria rubra were grown under greenhouse. Photosynthetic rates of leaves for P. hispidum and P. rubra which were subjected watering were 6.3 and 9.8μmol·m^-2.s^-1 at environmental CO₂ concentration, saturated light density and leaf temperature of 26℃, respectively. Photosynthetic rate of leaves for P. hispidum decreased by 0.38μmol·m^-2·s^-1 during leaf water potential(ψ)declined by 1 bar at lower leaf/air water vapor gradient (△w ). Photosynthetic rate (PN) decreased as △w increased and the relationship was PN=7.02-0.06△w, r²=0.7. The slope of this relationship between PN and △w, decreased during lowing ψ.For P. rubra, the similar response of PN on decreasing ψ was found, but the response of PN on changing △w was more sensitive than that of P. hispidum. The relationship between PN and △w for P.rubra was PN=11.16-0.1△w, r²=0.65.Leaf conductance (g) for these shruhs were much alike at higher ψ, such as -8 bar or -8.75 bar for each, but the change of g in leaves of P.rubra was greater than that of P. hispidum during increasing △w, Lowing ψ could increase water use efficiency(WUE)for both shrubs. And WUE decreased during increasing △w. The results showed that the response of P. rubra which habited in subtropical monsoonal forest was more sensitive than that of P. hispidum which habited in tropical rain forest.

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