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作 者 ：付为国;李萍萍;陈歆;卞新民;陈冬梅

期 刊 ：武汉植物学研究 2005年 23卷 6期 页码：555-559

关键词：虉草；净光合速率；光合作用响应曲线；蒸腾速率；

Keywords:Phalaris arundimacea, Net photosynthetic rate, Light-response curve of photosynthesis, Transpiration rate,

摘 要 ：采用便携式LI-6400光合测定仪,在晴朗的天气,对虉草成熟叶片净光合速率(Pn)以及光合有效辐射(Par)、气孔导度(Cond)、细胞间CO₂浓度(Ci)、叶温(Tl)、叶周围气温(Ta)和蒸腾速率(Tr)等影响因子进行田间测定,研究虉草的光合日变化。结果表明:虉草净光合速率日变化呈双峰曲线,主峰出现在10:00,次峰出现在15:00,光合“午休”现象明显,非气孔限制是产生“午休”的主要原因。净光合速率变幅为5.86~20.64μmol·m^-2·s^-1,蒸腾速率变幅为2.8~6.22mmol·m^-2·s^-1,光补偿点为40μmol·m^-2·s^-1,光饱和点为2100μmol·m^-2·s^-1(自然状态下达不到),表观光量子效率为0.0565mol·mol^-1,暗呼吸速率为2.26μmol·m^-2·s^-1,水分利用效率为2.31~3.65μmol·mmol^-1。数据显示,虉草是一种高光效植物,对于其资源的合理利用及其对湿地生态系统的稳定意义重大。

Abstract:Photosynthetic characteristics were studied in mature leaves of Phalaris arundimacea using portable LI-6400 photosynthesis instrument(Licor,USA) in the field.The diurnal changes of net photosynthetic rate and its major affecting factors,including photosynthetically active radiation(Par),stomatal conductance(Cond),intercellar CO₂ concentration(Ci),leaves temperature(Tl),air temperature(Ta),transpiration rate(Tr),were measured.The results showed that the diurnal process of photosynthetic rate exhibited a double peak curve in which the main peak appeared around(10:00),and the second around(15:00).This may reflected an obvious phenomena of midday depression of photosynthesis caused by Non-stomatal limition.Diurnal variation of net photosynthetic rate is 5.86-20.64 μmol·m^-2·s^-1,and transpiration rate is 2.8-6.22 mmol·m^-2·s^-1.And the other parameters,light compensation point is 40 μmol·m^-2·s^-1,light saturation point 2100 μmol·m^-2·s^-1,apparent quantum yield 0.0565 mol·mol^-1,dark respiration rate 2.26 μmol·m^-2·s^-1,and water use efficiency is 2.31-3.65 μmol·mmol^-1.The data showed that P.arundimacea was a kind of highly photosynthetic efficiency plant,illuminating for the exploitation of resources and maintaining the eco-stability of wetland ecosystem.

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