低温胁迫下不同果蔗品种光合及荧光特性的变化及耐寒性评价

以6个果蔗品种幼苗为试材,研究低温（0℃）胁迫对各品种叶片的叶绿素含量、气体交换参数及叶绿素荧光参数等指标的影响,利用隶属函数对果蔗品种的抗寒性进行综合评价。结果表明,随着低温胁迫时间的延长,‘桂果蔗1号’和‘拔地拉’的叶绿素（Chl）含量先上升后下降,其余4个果蔗品种幼苗叶片Chl含量持续下降;低温胁迫下,6个果蔗品种的净光合速率（Pn）、气孔导度（Gs）和蒸腾速率（Tr）显著下降,但胞间CO2浓度（Ci）、水分利用效率（WUE）和气孔限制值（Ls）却显著增加,说明光合作用的下降主要由非气孔因素引起;在叶绿素荧光参数方面,低温胁迫下6个果蔗品种的初始荧光（Fo）和非光化学淬灭系数（NPQ）呈上升趋势,而PSⅡ最大光化学效率（Fv/Fm）、光化学淬灭系数（q P）和PSⅡ实际光化学量子产量(ΦPSⅡ)均显著下降,表明低温对PSⅡ反应中心的电子传递潜力产生明显的抑制。用隶属函数法综合评价抗寒性由强到弱依次为:‘桂果蔗1号’>‘拔地拉’>‘闽引黄皮果蔗’>‘白玉果蔗’>‘龙黑果蔗’>‘川蔗26号’。 

Changes of Photosynthetic Fluorescence and Evaluation of Cold Resistance Under Cold Stress for Different Chewing Cane Varieties

The chlorophyll content, gas exchange parameters and chlorophyll fluorescence parameters of six chewing cane cultivars seedlings were studied in artificial simulation low temperature environment(0℃). Cold tolerance of chewing cane cultivars was comprehensively evaluated by using membership function based on cold resistant coefficient of these indexes. With increasing time of low temperature, the chlorophyll(Chl) content of 'Guiguozhe1' and 'Badila'seedlings increased initially and then decreased, whereas that of the other four seedling types continuously decreased. The net photosynthetic rate(Pn), stomata conductance(Gs) and transpiration rate(Tr) all decreased evidently, but the intercellular CO2 concentration(Ci), water use efficiency (WUE) and stomatal limitation(Ls) increased significantly under the low temperature stress. It is suggested that non-stomatal limitation became the mainly cause of the reduction of Pn in chewing cane seedlings; About the chlorophyll fluorescence,the initial fluorescence(Fo) and the non-photochemical quenching  coefficient(NPQ) increased gradually, the maximal photochemical yield(Fv/Fm), photochemical quenching coefficient(qP) and the actual photochemical efficiency of system II(ΦPSII) decreased continuously under the low temperature of 6 chewing cane cultivars. It indicated that low temperature produced significant inhibition on the electron transfer potential of PSII reaction centers. Evaluation on cold tolerance of six chewing cane cultivars seedlings were made through fuzzy comprehensive evaluation method, the cold tolerance order was 'Guiguozhe1'>'Badila'>'Minyin huangpi guozhe'>'Baiyu guozhe'> 'Longhei guozhe'>'Chuanzhe26'.