掌叶半夏的光合特性及影响因子分析

Analysis of Photosynthetic Characteristics and Its Influencing Factors of Pinellia pedatisecta Schott

探讨掌叶半夏的光合特性及其影响因子,为指导掌叶半夏的人工种植提供依据。本研究选择掌叶半夏成熟的叶片,利用LI-6400型便携式光合仪测定了植株叶片的光合-光响应曲线、光合日变化。结果表明,掌叶半夏的光饱和点、光补偿点(LCP)和表观量子效率(AQY)分别为1000μmol/(m^2·s)、18.44μmol/(m^2·s)和0.0318。较低的LCP表明掌叶半夏为喜阴性植物。掌叶半夏净光合速率的日变化呈双峰曲线,存在明显的"午休"现象。相关性分析表明,蒸腾速率和光合有效辐射是影响掌叶半夏净光合速率的主要因子,相关系数分别为0.721和0.718。掌叶半夏在栽培时,可采取与其他作物,如玉米、小麦、高粱和油菜等间作的方式,对其遮阴;同时,合理灌溉,保持环境相对湿度,使植株的蒸腾速率降低从而缓解"午休"现象。由于掌叶半夏的光饱和点为1000μmol/(m^2·s),因此,遮荫的光照强度不应低于1000μmol/(m^2·s)。

In order to provide an evidence for guiding artificial planting of P. pedatisecta, the light-responsecurves and diurnal photosynthesis（Pn） of mature leaves were measured with LI-6400 system. The resultsshowed that the critical points of light saturation and light compensation（LCP）, apparent quantum yield（AQY）of P. pedatisecta was 1000 μmol/（m^2·s）, 18.44 μmol/（m^2·s） and 0.0318 respectively. The lower LCP indicatedthat P. pedatisecta was a shade-loving plant. The curve of diurnal variation of net photosynthetic rate of leavesof P. pedatisecta had two peaks, and there was a significant‘midday depression＇at noon. Correlation analysisshowed that the Pn was correlated significantly with Tr and PAR, with the correlation coefficient of 0.721 and0.718 respectively. The P. pedatisecta was a shade-loving plant, therefore, it was suggested that intercroppingof P. pedatisecta with tall crops, such as maize, wheat, sorghum and rape, could get shadowy environment,decrease midday depression of photosynthesis. Another way to decrease midday depression of photosynthesiswas reasonable irrigation for maintaining the relative humidity of the environment. The light saturated point of P. pedatisecta was 1000 μmol/（m^2·s）, so the light intensity of the shadowy environment could not be lower than1000 μmol/（m^2·s）.