光照对多花黄精生长、光合和叶绿素荧光参数特征的影响

Effect of Light Intensity on Growth,Photosynthetic and Fluorescence Characteristics of Polygonatum cyrtonema Hua

以多花黄精（Polygonatum cyrtonema Hua）块茎盆栽苗为试材,采用遮阳网遮光方法设置透光率100%、75%±5%、45%±5%、15%±5%4种处理,调查测定多花黄精生长状况和光合、叶绿素荧光参数,探讨多花黄精对光照的响应与适应机制。结果表明：75%及以上高透光率时多花黄精成活率达100%,后随透光率的下降,存活率极显著降低;植株叶面积、地径、株高在过高或过低透光率下均较45%~75%透光率时减小,比叶重75%透光率下最高;随透光率的下降,叶绿素a、叶绿素b、叶绿素（a＋b）含量均先升高后降低,而叶绿素a/b和类胡萝卜素则相反;光照对多花黄精净光合速率日进程、表观量子效率并没有明显影响,但对蒸腾速率日进程有影响。随透光率的下降,最大净光合速率先升高后降低,光补偿点、光饱合点和暗呼吸速率则持续降低;光照对多花黄精PSⅡ原初光能转换效率影响不明显,但高透光率或低透光率对其他叶绿素荧光参数影响明显,而且高透光率的影响比低透光率影响大。综合表明多花黄精弱光环境下对蓝光利用能力强,具较强的耐荫特征,而且对光环境适应性宽,适宜于透光率45%~75%的条件下良好生长。

We evaluated the ecological adaptability of Polygonatum cyrtonema Hua to different light conditions and determined the photosynthetic,fluorescence characteristics and growth performances of P.cyrtonema Hua.The survival rate was 100%,when the light intensity was equal or greater than 75% of full light,and the survival rate of P.cyrtonema Hua significantly reduced with die decreasing of the light intensity.Leaf area,basal diameter,and height of individual of P.cyrtonema Hua reached peak value at 45%-75% of full light,and specific leaf weight was the highest under 75% of light transmittance.When decreasing the light intensity,the contents of Chl a,Chl b and Chl contents increased firstly and then decreased,while the rate of Chl（a/b）and Car content changed in the inverse trend.Light had significant effect on T_r of P.cyrtonema Hua,while it showed no significant effect on P_n diurnal progress.When light intensity increased,Pmax decreased firstly and then increased.LCP and LSP decreased,while AQY changed insignificantly.Light intensity had significant effect on fluorescence parameters,while light intensity showed insignificant effect on F_v/F_m.Low light intensity influenced fluorescence parameters more obviously than that of high light intensity.Therefore,P.cyrtonema Hua is tolerant to low light environments which had high utilization efficiency in blue light,and it can grow well under 45%-75% of full light.