不同菜心品种叶绿素荧光参数日变化的研究

Study on Diurnal Changes of Chlorophyll Fluorescence Parameters of Different Cultivars of Flowering Chinese Cabbage

了解菜心光能利用效率的规律性,可为具优良光合性状菜心品种的选育提供参考。据此,本研究选用在二份耐热性强和二份耐热性弱的菜心品种作为研究对象,探讨了这些品种的叶绿素荧光参数的日变化规律。结果表明:随着光强和温度的上升和下降的日变化,四份菜心材料的初始荧光(Fo)、相对可变荧光(VJ)和单位反应中心热耗散能量(DIo/RC)出现先升后降的趋势,而最大荧光(Fm)、光能转化效率(Fv/Fm)、光化学性能指数(PIABS)则出现先降后升的情况;除Fo的最大峰值在四份材料中均在13:00时外,耐热性强的材料其余参数的最大或最小峰值出现在光照强度最大的13:00时且变化幅度较小,而在耐热性弱的材料中这些值的变化幅度大且出现在日最高温度的14:00。另外,随着光强和温度的降低,各荧光参数又逐渐向初始水平恢复,但耐热性强的菜心品种的恢复速率高于耐热性弱的菜心品种。这一结果表明叶绿素荧光参数可考虑作为评价菜心材料耐热性强弱的一个参考指标。

Understanding the regularity of light-use efficiency could provide references for pyramiding superior photosynthetic traits in the breeding program of flowering Chinese cabbage. In this study, the diurnal variation of chlorophyll fluorescence parameters of flowering Chinese cabbage were monitored by using two heat-tolerant and two heat-sensitive cultivars. The results show that the parameter values of Fo, VJand DIo/RC had a regularity of low-high-low with the diurnal variations of light intensity and temperature in four flowering Chinese cabbage cultivars, while the values of Fm, Fv/Fmand PIABS had a high-low-high tendency. In addition to the maximum peak value of Fo in the four cultivars was at 13：00, the maximum or minimum peak value of other parameters in the heat-tolerant cultivar had small changes and appeared at 13：00 when the light intensity was highest, while the change of these values in heat-sensitive cultivars was large and appeared in the daily maximum temperature of 14：00.With the decrease of light intensity and temperature, the values of all fluorescent parameters gradually recovered tothe initial level, but the recovery rate in two heat-tolerant cultivars were generally higher than those in two heat-sensitive cultivars. These results indicated that the chlorophyll fluorescence parameters could be considered as a reference indexes to evaluate the levels of thermotolerance in flowering Chinese cabbage.