桔梗光合生理特性研究.doc

1 桔梗光合生理特性研究【摘要】目的研究桔梗光合生理特性, 为桔梗栽培管理提供参考。方法利用 Li-6400 便携式光合作用系统测定桔梗光合作用光响应曲线( Pn-PAR ) 以及净光合速率日变化规律。结果桔梗饱和光强( SL )为 1 μ mol · m-2 · s-1 ,光补偿点( LCP )为 μ mol · m-2 · s-1 ;桔梗净光合速率( Pn ) 日变化呈双峰曲线, 上下午各有一个高峰,午后有典型的“午休”现象。第 1 峰出现在上午 11: 00, 净光合速率( Pn )为 μ mol · m-2 · s-1 ,第2 峰出现在 15: 00 ,净光合速率( Pn )为 μ mol · m-2 · s-1 。 14: 00 时, 净光合速率( Pn )为 μ mol · m-2 · s-1, 是一天中的最低值; 桔梗净光合速率( Pn )午后降低出现光合“午休”是由气孔限制因素和非气孔限制因素共同作用引起, 而气孔非限制因素起主要作用。结论桔梗的光合特性表明为典型的阳生植物, 对光照的适应性较强,在生产上宜选择光照条件好的地块, 并加大种植密度,以提高桔梗的产量。【关键词】桔梗饱和光强光补偿点光合速率日变化 2 Abstract : ObjectiveTo provide references of cultivation management, the photosynthetic physiological characteristics of Platycodon grandiflorum were studied. MethodsPhotosynthesis light response curve (Pn-PaR) and the diurnal change law photosynthetic rate were determined by Li-6400 portable photosynthesis system. Results The Saturation light intensity (SL) of P. grandiflorum was μ mol · m-2 · s-1 and its pensation point (LCP) was μ mol · m-2 · s-1 . The diurnal changes photosynthetic rate (Pn) presented a double-apex curve. The first peak appeared at 11∶ 00 am when its Pn was μ mol · m-2 · s-1 . The second one occurred at 15∶ 00 pm when its Pn was μ mol · m-2 · s-1 . The lowest Pn was μ mol · m-2 · s-1 at 14∶ 00 pm during one whole day. The phenomenon of“ noon break ” caused by stomatal limitation and non-stomatal limitation played a major role. Conclusion Photosynthetic Characteristics of P. grandiflorum indicates that it isa typical sun plant and has strong adaptability to high light. To increase yield, it is necessary to select a place in good light condition for them and to add plant density. Key words : Platycodon grandiflorum; Satuation light intensity; pensation point; The diurnal change of 3 photosynthetic rate 桔梗 platycodon grandiflorum (Jacp.) ,属于桔梗科药用植物, 根为常用大宗药材, 具有宣肺、利咽、祛痰、排脓的功效[1]。桔梗既是一种资源植物又是一种药、食、赏兼用的经济植物。由于桔梗越来越多的药用价值与经济价值被发现,导致其用量大增,野生资源不能满足市场的需求[2]。目前, 大面积的人工栽培桔梗已经逐步代