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CO_2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(r^2=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(r^2=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^(-1)CO_2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。
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 CO_2 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, r^2=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, r^2=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.
出处
《武汉植物学研究》
CSCD
1990年第3期254-260,共7页
Journal of Wuhan Botanical Research
关键词
热带
亚热带
灌木
光合作用
缺水
Piper hispidum
Psychotria rubra
Photosynthesis (PN)
Leaf water potential(ψ)
Leaf/air water vapor gradient (△w)
Water use efficiency(WUE)
