过量合成ALA转基因烟草叶片光合与叶绿素荧光特性的研究  

Study on Leaf Photosynthesis and Chlorophyll Fluorescence of Transgenic Tobacco Over-producing 5-Aminolevulinic Acid(ALA)

作　　者：张治平[1] 汪良驹[1] 姚泉洪[1] 

机构地区：[1]南京农业大学园艺学院,南京210095

出　　处：《西北植物学报》2008年第6期1196-1202,共7页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家自然科学基金资助(30471181)

摘　　要：以转酿酒酵母Hem1基因的转基因烟草和野生型植株为材料,用Li-6400光合测定仪和PAM-2100叶绿素荧光仪检测了2种烟草不同叶位叶片光合和荧光参数,并考察了它们的生长情况.结果表明:过量合成ALA的转基因烟草植株具有更强的光合能力,并伴随着气孔导度(Gs)和蒸腾速率(Tr)提高.暗适应下转基因植株不同叶位叶片的初始荧光(Fo)没有明显差异,而野生型植株下部叶片F0明显升高;转基因植株最大荧光(Fm)、可变荧光(Fv)、PSⅡ最大光化学效率(Fv/Fm)等参数均显著提高,特别是下部叶片表现得更为明显;在光照下,转基因植株PSⅡ有效光化学效率(Fv′/Fm′)和实际光化学效率(ΦPSⅡ)、荧光猝灭系数(qP)、电子传递速率(ETR)、光化学效率(Pc)以及进入PSⅡ反应中心的能量(Pc+Ex)普遍高于野生型,而天线热耗散能量(Hd)以及非光化学荧光猝灭系数(NPQ)等明显低于野生型,且这些差异在基部叶片中表现得尤为突出.可见,过量合成ALA有利于延长烟草叶片光合寿命,提高光化学能量转换效应和光合产物积累,从而促进植株生长.Transgenic tobacco plants carrying a binary recombinant gene comprised of Arabidopsis thaliana hemAl promoter and Saccharomyces cerevisiae Hem 1 could over produce 5-aminolevulinic acid （ALA） exposed to light. It could also significantly raise the net photosynthetic rate,stomatal conductance and transpiration rate of the leaves. Measurement of chlorophyll fluorescence of the dark-adapted leaves revealed that the minimal fluorescence iF0 ） was not obviously different among leaf positions in the transgenlc plants,but that of the base leaves raised distinctly in the wild type ones. Meanwhile,the maximum fluorescence （Fro） ,the variable fluorescence （Fv） and the PSⅡ maximal photochemical efficiency （Fv/Fm） of the base leaves in transgenic tobacco were all significantly higher than that of the wild type. When seedlings were exposed to light,it was then observed that, the chlorophyll fluorescence parameters including the photochemical efficiency of PS Ⅱ （Fv＇/Fm＇）, PS Ⅱ actual photochemical efficiency （φPS Ⅱ ）, photochemical quench （qP） ,electronic transfer rate （ETR）, photochemistry（Pc）, and energy entering PS Ⅱ center（Pc＋ Ex） were generally higher than that of the wild type,whereas the antenna heat dissipation （Hd）,non-photochemical quench （NPQ） were much lower than that of the wild type. These differences were most significant in the base leaves, suggesting that the over-production of ALA could prolong leaf photosynthetic life,enhance photochemical conversion efficiency,increase photosynthate accumulation and promote plant growth.

关 键 词：转基因烟草 拟南芥HemA1启动子 酿酒酵母Hem1 ALA 光合气体交换 叶绿素荧光 

分 类 号：Q789[生物学—分子生物学]