不同温度下秋茄树幼苗叶绿素荧光参数对光强的响应

Response of Chlorophyll Fluorescence Parameters of Kandelia obovata Seedlings to Light Intensity in Incubator with Different Temperature

为了更好地开展秋茄树Kandelia obovata的引种、繁育等工作,以其2年生移植容器苗为材料,设置了昼夜温度分别为A(25/20℃),B(20/15℃),C(15/10℃)和D(10/5℃)共4个处理,研究了电子传递速率(ETR)、光系统Ⅱ(PSⅡ)反应中心的激发能捕获效率(Fv’/Fm’)、PSⅡ反应中心电荷分离实际量子效率(ΦPSⅡ)、光化学猝灭系数(qP)和非光化学猝灭系数(qN)等参数对光强(PAR)的响应曲线。结果表明,光响应机理模型和双指数模型可以较好地拟合不同温度处理下秋茄树幼苗ETR对PAR的响应,所得结果与实测值较为接近(P>0.05);在不同温度下,秋茄树幼苗叶片的饱和PAR有所差异,在1000~1400μmol·m^-2·s^-1之间;以光响应机理模型拟合的结果为例,在A,B,C,D不同处理下,秋茄树叶片的最大电子传递速率(ETRmax)间均有显著差异(P(27)0.05),分别为124.393,110.812,64.153和33.427μmol·m^-2·s^-1;D处理下的Fv’/Fm’,ΦPSⅡ,qP和qN均处于最低水平,说明5℃以下低温对秋茄树幼苗的光合影响较大。因此,建议在幼苗阶段,夏季进行适当遮阳,冬季喷施植物生长调节剂或采用其他措施进行保温。

In spring of 2017,container Kandelia ogovata seedlings were transplanted into plastic drum and in January 2019,experiments were conducted after 7 days slow rooting.Seedlings were treated in incubators with different day-night temperature such as 25/20℃(A),20/15℃(B),15/10℃(C)and 10/5℃(D).The results showed that the response of electron transfer rate(ETR)to the light intensity of different treated seedlings could be fitted well by the light response mechanism model and the double exponential model.The fitted values were close to the measured ones.The light saturation points of the leaves of different treated seedlings ranged from 1000μmol/m2/s to 1400μmol/m^2/s.Taking the result of model fitting by light response mechanism as an example,the maximum electron transfer rates of seedling leaves were significantly different at different temperatures(P(27)0.05),which were 124.393,110.812,64.153,and 33.427μmol/m2/s,respectively.Seedligns with treatment of D had the lowest excitation energy capture efficiency of PSⅡ(Fv’/Fm’),the actual photochemical quantum efficiency of PSⅡ(ΦPSⅡ),photochemical quenching coefficient(qP)and non-photochemical quenching coefficient(qN).It indicated that the low temperature had significant effect on the photosynthesis of K.ogovata seedlings.