摘要
以银杏叶片为试材,在不同温度下采用连续激发式植物效率仪PEA测试强光照射对快速叶绿素荧光诱导动力学参数的影响,利用CIRAS-2型便携式光合系统进行光合光转化效率LCE的光强响应测试。结果表明:银杏光抑制不仅呈现光强剂量效应,而且呈现温度剂量效应。当光强超过约1000μmol·m-2s-1时银杏LCE最低,为较严重的光抑制过程。在25℃常温下超过1000μmol·m-2s-1光强照射20min时银杏Fv/Fm下降加快;15℃以下低温和35℃以上高温均会使Fv/Fm进一步降低;而且热胁迫比冷胁迫的光抑制程度更大,因为25～45℃下Fv/Fm的直线回归斜率/kheat/比5～20℃的/kchilling/增大了15.4%。5～10℃的低温强光引起银杏叶片热耗散DIo/RC略微增加,而35℃以上高温强光会导致热耗散DIo/RC剧增。冷胁迫会降低PSⅡ反应中心数目,但是热胁迫会使之降低更多。冷热胁迫下强光引起的光抑制(Fv/Fm)与PSⅡ反应中心数目RC/CSo或RC/ABS与之间高度正相关。因此,PSⅡ的异质性即PSⅡ反应中心的可逆失活是冷热胁迫下光合机构发生光抑制的保护机制。
A fast chlorophyll transient fluorescence and its dynamic parameters were measured by a PEA （Plant Efficiency Analyzer from Hansatech）, in the leaves of Ginkgo （ Ginkgo biloba） after illumination of strong light with chilling stress or heat stress, respectively. In addition, a response of light on LCE （light conversion efficiency of photosynthesis） was measured by a CIRAS-2 of the portable photosynthesis systems. The results indicated that photoinhibition in leaves of Ginkgo showed a dosage effect of not only the light intensity but also the temperature. LCE was lowest and showed more serious photoinhibition over about 1 000 μmol·m^-2s^-1 PAR （photosynthetic available radiation）. At 25 ℃, Fv/Fm in the leaves of Ginkgo showed accelerating decline after illuminating for 20 min at PAR 1 000 μmol· m^-2s^- 1 or more on the leaf of Ginkgo, and the Fv/Fm showed more serious decline at low temperature of 15 ℃ or lower and high temperature of 35 ℃ higher. Meanwhile, photoinhibition exhibited more serious when treated by chilling stress than by heat stress, because absolute value of the slope of linear regression equation （kheat） between Fv/Fm and temperature form 25 ℃ to 45 ℃ increased 15.4% than absolute value of kchilling from 20 ℃ to 5 ℃. The strong light caused a modest little increase of energy dissipation DIo/RC at chilling stress of 5 - 10 ℃, but a sharp increase of that at heat stress of 35 ℃ or higher 35 ℃. Density of PS Ⅱ reaction centers decreased at chilling stress, but it decreased more serious at heat stress than at chilling stress. There were remarkable correlations between photoinhibition （ Fv/Fm） caused by strong light at chilling stress and heat stress and density of PS Ⅱ reaction centers （RC/CSo or RC/ABS）. Therefore, the heterogeneity of PS Ⅱ , i.e. reversible inactivation of PS Ⅱ reaction center, is protection mechanism on photoinhibition of the photosynthesis apparatus.
出处
《林业科学》
EI
CAS
CSCD
北大核心
2008年第12期28-34,共7页
Scientia Silvae Sinicae
基金
国家自然科学基金(30571267)
关键词
冷胁迫
热胁迫
叶绿素荧光参数
光系统Ⅱ
光抑制
银杏
chilling stress
heat stress
chlorophyll fluorescence parameter
photosystem Ⅱ
photoinhibition
ginkgo
