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作 者 ：陈　婕;毛子军*;马立祥;夏莹莹

期 刊 ：植物研究 2008年 28卷 4期 页码：471-476

关键词：蒙古栎；紫椴；光环境转变；光合能力；叶绿素荧光；光抑制；光保护；

Keywords:Quercus mongolica, Tilia amurensis, light intensity transfer, photosynthetic capacity, chlorophyll fluorescence, photoinhibition, photoprotection,

摘 要 ：比较研究了从温室5%光强转到10%、30%和100%光强处理下，蒙古栎（Quercus mongolica）和紫椴（Tilia amurensis）幼苗的光合能力和叶绿素荧光的响应，揭示了两个树种对光环境变化的不同适应情况及其光保护机制。结果表明，光强转换后两种幼苗都发生了严重光抑制，蒙古栎幼苗的最大光化学效率（F_v/F_m）在光强转变后第3天降到最低（0.52），紫椴幼苗在光强转变后第1天就降到了最低（0.67），蒙古栎降低幅度明显高于紫椴。之后随着光适应时间的延长逐渐恢复到原有水平，说明短时期的光抑制没有对两种幼苗的光合机构造成光损伤；从不同光照条件来看，无论是最大净光合速率（P_max），还是实际光化学效率（ФPSⅡ），2种幼苗均为30%光强下的值高于10%和100%光强，说明过低或过高的光强都不利于幼苗的生长发育，只有适当的中光才利于幼苗的生长发育；与30%光强相比，蒙古栎幼苗100%光强下P_max、F_v/F_m、ФPSⅡ、NPQ的变化幅度远大于紫椴幼苗，表明高光强对蒙古栎幼苗的影响要大于紫椴；100%光强下，2种幼苗均通过大量增加非光化学淬灭（NPQ）、类胡萝卜素和叶绿素之比（Car/Chl）耗散过剩光能，降低单位鲜重叶绿素含量（Chl）以减少光能吸收，避免了光合机构光破坏。

Abstract:Dynamic chlorophyll fluorescence parameters and photosynthetic capacity of Quercus mongolica and Tilia amurensis seedlings were measured immediately after suddenly exposing to 10%, 30% and 100% daylight from greenhouse (5% relative light intensity). The aim of the study was to investigate the light acclimation and photoprotective mechanisms to the change of light environment on the two species. The results showed that: maximal photochemical efficiency of PSⅡ(F_v/F_m) decreased immediately on sudden exposure to 100% daylight, with the maximal decrease occurring 3 days (0.52) after transfer on Q. mongolica and 1 day (0.67) on T. amurensis. The decrease on Q. mongolica was obviously higher than that on T. amurensis. During the light acclimation, the F_v/F_m was followed by a subsequent recovery to the initial value, indicating that photodamage in the two species did not occur in the short term; the value of the photosynthetic capacity (P_max) and actual efficiency of PSⅡ (ФPSⅡ) under 30% daylight was higher than 10% and 100% daylight, indicating that relative to high and low light, moderate light was better to the growth of seedlings; the variation of P_max, F_v/F_m, ФPSⅡ, NPQ between 100% and 30% daylight in Q. mongolica was greater than that in T. amurensis, indicating that Q. mongolica was more susceptible to high light than T. amurensis; and the two species dissipated their excess light energy both depending on the increase of non-photochemical quenching of chlorophyll fluorescence (NPQ) and the Car/Chl ratio, and on the decrease of the Chl content.

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