不同耐弱光性茄子品种的叶绿素荧光参数比较

Comparisions of Chlorophyll a Fluorescence Parameters in Different Low-irradiance-tolerant Eggplant cultivars

根据快速叶绿素荧光诱导动力学原理,选用耐弱光茄子品种99-8和不耐弱光茄子品种黑又亮作试材,进行遮光(光照强度相当于自然光照的40%)15 d、未遮光(自然光照)15 d、遮光30 d和未遮光30 d 4个处理,用JIP-测定法对不同耐弱光性品种在不同光照条件下的叶绿素荧光特性进行研究。结果表明:在4个处理中,耐弱光茄子99-8的ψo(反应中心捕获的激子中用来推动电子传递到电子传递链中超过QA-的其它电子受体的激子占用来推动QA还原激子的比率)均高于不耐弱光茄子黑又亮,显示出99-8茄子具有更多的超过QA-的电子受体,如QB(次级受体醌)、PQ(质体醌)等。品种间最大光化学效率(φPo)差异不大,但99-8的PIABS(以吸收光能为基础的性能指数)和PICS(以单位面积为基础的性能指数)在两不同光照条件下均明显高于黑又亮。性能指数是对PSⅡ结构和功能的一个综合评定。通过以上研究我们得出如下结论:(1)拥有较多的超过QA-的电子受体和较高PSⅡ原初光化学反应效能是99-8耐弱光性强的一个原因。(2)性能指数与品种的耐弱光性密切相关,可以作为耐弱光性的一个鉴定指标。

The effects of low irradiance on chlorophyll a fluorescence kinetics were studied in two eggplant （ Solanum melongena L. ） cultivars： low irradiance tolerant cultivar 99-8 and low irradiance sensitive cultivar Black and Bright. Using JIP-test, the difference of chlorophyll a fluorescence parameters between the two cultivars was compared in 4 treatments： shaded （40% of nat- ural light intensity） 15 d, unshaded （natural lighting） 15 d, shaded 30d and unshaded 30 d. The higher ψo （Probability that a trapped exciton moves an electron into the electron transport chain beyond QA^- ） in 99-8 than that in Black and Bright showed that there were more electron acceptors beyond QA^- such as QB and PQ in 99-8. There was not difference between the maximum quantum yield of primary photochemistry （φPo） in two cultivars, but the performance index on absorption basis （ PIABS） and the performance index on cross section basis （PIcs） in 99-8 were more higher than that in Black and Bright in two irradiance condi-tions. The Performance index combines structural and functional criteria of PS Ⅱ . The results indicated that ： （ 1 ） the more elec- tron acceptors beyond QA^- and the higher effectiveness of primary photochemical reaction in PS Ⅱ is a reason why 99-8 is tolerant to low irradiance stress; （2） the performance index could be used to identify the low irradiance tolerant cultivars as there was a high correlation between the Performance index and the low irradiance tolerance of cultivars.