弱光对菊花‘清露’光合特性的影响

Effects of Low Light on Photosynthetic Characteristics of Chrysanthemum morifolium Cultivar ‘Puma sunny'

以弱光敏感的菊花品种‘清露’为试材,采用分析光合参数的方法,在自然光照(对照)和30%光照(弱光处理)2个条件下,研究了不同光强梯度(1 500、1 200、1 000、800、600、400、200、150、100、50、20、0μmol·m^(-2)·s^(-1))下植株在0、5、10、15、20d各时间点的光合特性变化,以探讨弱光对菊花光合特性影响规律,为苗期管理提供参考。结果表明:随着光合有效辐射(PAR)的提高,净光合速率呈上升趋势,在弱光条件下也是如此,对照净光合速率(Pn)最大值达到15.31CO_2μmol·m^(-2)·s^(-1),而弱光下最大值仅达到7.94CO_2μmol·m^(-2)·s^(-1);光饱和点(LSP)最大值分别为1 061.00、825.00μmol·m^(-2)·s^(-1);光补偿点(LCP)最大值分别为58.7、76.42μmol·m^(-2)·s^(-1);对气体交换参数进行分析,发现弱光下植株通过增大气孔导度(Gs),减少胞间二氧化碳浓度(Ci),来减缓因光照不足而造成的光合速率下降;然而弱光下菊花虽然通过自身调节来适应环境变化,但低光照仍会造成其光合速率的下降,影响植株的正常生长。这种效应既与气孔限制有关,又受非气孔因素的影响。

In order to study the effects of weak light on the chrysanthemum photosynthetic characteristic,in order to improve the seeding stage management.Chrysanthemum morifolium‘Puma sunny＇was used for experiment materials,natural light（CK）and 30%light（low light）two conditions were set,LI-6400 portable photosynthetic apparatus were used to measure photosynthetic parameters in 0days,5days,10 days,15days,20 days and the photosynthetic response curves were obtained under 1 500,1 200,1 000,800,600,400,200,150,100,50,200μmol·m^-2·s^-1 of different light.The results showed that with the increasing of PAR,the net photosynthetic rate showed an upward trend,and the same was true in the light of the weak light conditions.Under the condition of weak light treatment,the photosynthetic rate was lower than that of natural light;net photosynthetic rate Pn,the control group reached maximum 15.31CO_2μmol·m^-2·s^-1,while the low-light only reached the maximum 7.94CO_2μmol·m^-2·s^-1;light saturation point（LSP）maximum were1 061.00μmol·m^-2·s^-1,825.00μmol·m^-2·s^-1;light compensation point（LCP）maximum respectively58.7μmol·m^-2·s^-1,76.42μmol·m^-2·s^-1.The gas exchange parameters were analyzed,and the plants were found to moderate the decline of the photosynthetic rate resulted from the lack of light,by increasing the stomatal opening and decreasing the intercellular carbon dioxide concentration;under the low light,although the chrysanthemum try to adapt to the environment changed by its own adjustment,the low light would still cause the decline of its photosynthetic rate,and affect the normal growth of the plant.This effect was not only related to the stomatal limitation,but also affected by the non-stomatal factors.