摘要
生长在沙漠地区的植物经常遭受夏季正午短时间的高温胁迫,这在很大程度上限制了荒漠植物的光合作用。为了研究不同温度处理对塔克拉玛干沙漠南缘本土植物花花柴(Karelinia caspica)光系统Ⅱ(PSⅡ)的影响,分别在35、38、42、45、48、52℃和55℃下胁迫15min后,测定其叶绿素荧光诱导曲线。结果表明:(1)叶片温度超过42℃后,PSⅡ最大光化学效率(Fv/Fm)、单位面积上反应中心的数量(RC/CSo)、叶功能指数(PIABS)等PSⅡ荧光指标分别出现明显的升高或降低。(2)在45℃时,Fv/Fm、RC/CSo、PIABS等PSⅡ荧光指标出现大幅的升高或降低。(3)大于52℃时各指数出现极值。因此,42℃为花花柴正常生长的热阈值,超过此温度,会对花花柴的生长造成抑制;45℃为花花柴的PSⅡ的结构和功能受到伤害的阈值;52℃为失活的阈值,超过52℃,花花柴的PSⅡ反应中心将发生不可逆失活。
To assess effect of high temperature on photosynthesis of Karelinia caspica, an experiment was conducted at the southern fringe of the Taklimakan desert. We investigated the chlorophyll a fluorescence induction kinetics underlying heat-induced inhibition of photosystem Ⅱ （PS Ⅱ ） of K. caspica after 15 min heat stress treatment. The result indicated that the maximum fluorescence （Fm）, the maximum photochem- ical efficiency of PS Ⅱ （Fv/Fm）, the number of active reaction centers per cross-section （RC/CSo）, per- formance index on absorption basis （PI/ABS） and chlorophyll fluorescence transients changed little at 35-42 ℃, and drastically at 45-55 ℃. Moreover, at 45 ~C showed a clear ＂K＂ step in the chlorophyll fluorescence transients of K. caspica, point of K. caspica is 45 and become inactivity at 55 ℃. We conclude that the temperature sensitivity ℃ and inactivity point is 52 ℃
出处
《中国沙漠》
CSCD
北大核心
2013年第5期1371-1376,共6页
Journal of Desert Research
基金
新疆维吾尔自治区科技计划项目(201130106-3)资助
