光强对药用白菊花生长发育及光合特性的影响

Effects of light intensity on growth and photosynthetic characteristics of Chrysanthemum morifolium

目的：探讨光强对药用白菊花生长发育及光合特性的影响，为生产栽培提供理论依据。方法：测定不同光强处理（透光率分别为100％，80％，60％，40％，20％）下药用白菊花生长发育指标及光合色素含量，并利用LI-6400型便携式光合作用测定仪及PAM-2100荧光仪测定叶片的光合指标及叶绿素荧光参数。结果 随相对光强的减弱，药用白菊花主茎直径减小，植株高度、叶长、叶宽及长宽比均呈增大趋势，同化产物含量降低；光合色素含量在光强为100％-40％均逐渐增加，20％处理下有所下降，叶绿素a／b值减小；光补偿点降低，表观量子效率（AQY）先升高后下降，净光合速率（Pn）、气孔导度（Gs）、胞间CO2浓度（Ci）和蒸腾速率（Tr）均呈下降趋势，气孔限制值（L8）增大；荧光参数PSⅡ最大光能转换效率（Fv／Fm）升高，作用光下实际的PSⅡ光化学效率（φPSⅡ）、PSⅡ有效光化学量子效率（Fv＇／Fm’）、电子传递速率（ETR）、光化学淬灭系数（qP）在相对光强100％～60％处理下依次升高，非光化学淬灭系数（NPQ）依次下降，相对光强小于40％时，φOPSⅡ等参数下降，NPQ升高。结论：中度以下弱光条件不利于药用白菊花的生长发育，栽培生产中应以相对光强80％～60％的遮荫度为宜。

Objective： To investigate the effect of light intensity on growth and photosynthetic of Chrysanthemum morifolium. Method： The growth characteristics of C. morifolium were measured under different treatments （100%, 80%, 60%, 40% and 20% of full sunlight）. The photosynthetic characteristics and chlorophyll fluorescence parameters of leaves under different light intensity were determined by a LI-6400 photosynthesis system and a PAM-2100 chlorophyll fluorescence system. Result： With the reduction of irradiance, the diameter of the stem reduced, plant height, leaf length, leaf width and length/width raised, assimilation product increased; Content of photosynthetic pigment increased between light intensity 100%-40%, reduced under 20% treatment, chlorophyll a/b decreased. Light compensation point （LCP）, apparent quantum yield （AQY） increased first and reduced later, photosynthesis rate （Pn）, stomatal conductance （ Gs ） , intercellular CO2 concentration （ Ci ） and transpiration rate （ Tr ） decreased, stomatal limitation value （Ls） rose. Chlorophyll fluorescence parameters Fv/Fm increased, φPSⅡ , Fv＇/Fm＇, ETR and qP increased between irradiance 100% -60%, NPQ decreased, such as φPSⅡ decreased and NPQ increased when irradiance was lower than 40%. Conclusion ： Weak light condition was unfavorable to the growth of C. morifolium and the hght conditions of culture should be control between 80% -60% of full sunlight.