紫茎泽兰生殖期光合特性日变化

Characteristics of photosynthetic diurnal variation at the reproductive stage of Eupatorium adenophorum

在自然条件下,采用CI-340光合测定系统对紫茎泽兰(Eupatorium adenophorum)生殖期光合生理特性日变化及其与环境因子关系进行了研究,从而探讨紫茎泽兰生殖期光合特性,为其防控提供理论依据。结果表明,紫茎泽兰在生殖期时净光合速率日变化呈"双峰"型曲线,峰值分别在11:00和13:00左右出现,有明显的"午休"现象;气孔导度和蒸腾速率在9:00-14:00均与净光合速率变化趋势一致,随后均有所上升,全天呈"三峰"型变化趋势;胞间CO2浓度与气孔限制值呈"单峰"型变化,两者呈极显著负相关(R=-0.997 6**)。各环境因子在紫茎泽兰生殖期主要通过蒸腾速率、叶片水压亏缺和叶面温度的作用而影响净光合速率,光合有效辐射对其净光合速率具有决定性作用(R=0.860 0**)。通过本研究,在综合防除紫茎泽兰措施中如选择更强光合作用的替代植物、除草剂类型的筛选以及化学防除时期的选择等提供基础数据。

The CI-340 photosynthetic system was used to monitor the photosynthetic diurnal variation of Eupatorium adenophorum at the reproductive stage and determine the relationship between photosynthetic diurnal variation and environmental factors for providing the useful information for control E. adenophorum in natural condition. The results of this study indicated that the diurnal variation of net photosynthetic rate （Pn） presented a double-peak curve, peaking at 11：00 and 13.00, and this study also showed an obvious midday depression. The stomatal conductance （Gs） and transpiration rate （Tr） were positively consistent with Pn from 9：00 to 14：00, and then increased slightly, and they showed a three-peak curve. The intercellular CO2 concentration （Ci） was significantly negative correlation with stomatal limitation value （Ls） （R=-0. 997 6^＊＊ ）, presenting the single-peak curve. At the reproductive stage of E. adenophorum, Pn was mainly affected by Tr, Leaf Water Deficit and leaf temperature, and greatly regulated by photosynthetic active radiation （R=0. 860 0^＊＊）. This study suggested that the comprehensive control measures of E. adenophorum focused on choosing the more strongly photosynthesis replaced plants, herbicide, chemical control time.