合果木光合生理特性及水分利用特点的研究

[目的]了解合果木深圳大面积引种栽培后导致林下生物量少、土壤干燥等生态问题的原因。[方法]采用Li-6400便携式光合测定系统,研究合果木的光合生理特性,分析合果木的水分利用特点。[结果]经过充分光诱导和CO2诱导的合果木叶片光响应曲线符合非直角双曲线模型,CO2响应曲线符合二次曲线方程。合果木光饱和点低,为116.2μmol/(m2.s),表观光量子效率高达0.068±0.005μmol/mol,合果木利用低强度光的效率高。合果木水分需求量大。当达到光饱和后,净光合速率增长缓慢,但气孔导度和蒸腾速率仍随光强的增强明显增大,显示合果木在高光强下利用水分的能力差,水分需求量大。[结论]该研究对合理进行合果木的迁地保护和引种栽培有指导意义。

Photosynthetic Characteristics and Water Use Efficiency of Paramichelia baillonii of Magnoliacease

[Objective] The research aimed to find out the reasons for dried soil and few living plants under the trees of Paramichelia baillonii after which was introduced into Shenzhen.[Method] The Photosynthetic characteristics and water use efficiency of P.baillonii were measured in the field with Li-6400 Portable Photosynthesis System.[Result] The response of photosynthesis to photon flux density fitted well with the non-rectangular hyperbola model and the response of photosynthesis to CO2 concentration fitted well with a quadratic equation after the leaf induced by light and CO2 adequately.The light saturation point of P.baillonii was rather low of only 116.2 μmol/(m2·s),and the apparent quantum yield were high to 0.068±0.005 μmol/mol,indicating the plant's high efficiency in using low intensity light.P.baillonii needed mass water.The net photosynthetic rate leveled off when approximating the light saturation point,but the stomatal conductance and the transpiration rate kept the trend of rising,indicating P.baillonii was not efficient under the conditions of high light intensity.[Conclusion] This study had guiding significance in introduced culture and in ex situ conservation of P.baillonii.