脱水对生物结皮中齿肋赤藓光合色素含量和叶绿体结构的影响  

Effects of Dehydration on Photosynthetic Pigment Content and Chloroplast Ultrastructure of Syntrichia caninervis in Biological Soil Crusts

作　　者：魏美丽[1] 张元明[1] 

机构地区：[1]中国科学院干旱区生物地理与生物资源重点实验室,中国科学院新疆生态与地理研究所,新疆乌鲁木齐830011

出　　处：《中国沙漠》2010年第6期1311-1318,共8页Journal of Desert Research

基　　金：中国科学院知识创新工程重要方向项目(NKZCX2-YW-336);国家重点基础研究发展计划项目(2009CB825104)资助

摘　　要：通过脱水对生物结皮中齿肋赤藓叶绿体结构特征和光合色素含量的影响研究,结果表明,在脱水过程中,齿肋赤藓光合色素含量及叶绿体结构变化特征表现为4个阶段:①启动期,脱水0～2h,光合色素含量与完全湿润时差异不显著(P>0.05),此时透射电镜下叶绿体中基粒片层结构和类囊体清晰,纵向排列,叶绿体双层膜系统保持完好;②快速增加期,脱水2～6h内,光合色素含量快速升高,在脱水6h时达最大值,此时叶绿体结构发育最为充分,嗜锇颗粒数量最多且集中分布;③相对稳定期,脱水6～10h,光合色素含量在达到最大值后,逐渐降低,但差异不显著(P>0.05),叶绿体结构依然完整;④缓慢衰退期,脱水10h后,直至完全干燥,光合色素含量逐渐降低,完全干燥时叶绿体趋于解体。研究还表明,齿肋赤藓光合色素含量变化明显滞后于形态结构变化,其含量在完全湿润时并非最高,而在脱水6h时(RWC为26.4%)达最大值,而后随含水量降低而降低,与种子植物光合色素含量随含水量降低不同,这可能与其内部结构修复有关,再水化后光合色素完全恢复,说明齿肋赤藓光合色素对水分的响应是可逆的。Syntrichia caninervis is the dominant moss in biological soil crusts in the Gurbantunggut desert.In this paper,the effects of dehydration on photosynthetic pigment content and chloroplast ultrastructure of Syntrichia caninervis are studied.The results show that four phases can be clearly defined concerning the alternation of photosynthetic pigment content and chroloplast ultrastructure in the process of dehydration.（1）Initiation phase：The photosynthetic pigment content increased and there was no significant difference between wet and drought treatments after 2 hours of dehydration（P0.05）,whereas chloroplasts possessed clear longitudinally-distributed thylakoids and lamellar structure.The membrane system of various kind of cell structure remains intact.（2）Rapid increase phase：After 2—6 hours of dehydration,the photosynthetic pigment content increased and reached a maximum value after 6 hours of dehydration（RWC,26.4%）.At the same time,more osmiophilic particles appeared and were distributed more centralized;（3）Steady phase：After 6—10 hours of dehydration,the photosynthetic pigment content slowly began to decrease（P0.05）,and chloroplasts were still remained intact.（4）Slow decline phase：After 10 hours of dehydration,photosynthetic pigment content decreased with much lower water content.The structure of chloroplasts tended to disintegrate after fully dehydration.The results also indicate that the response of photosynthetic pigment content lags far behind that of structural changes,differing from the seed plants that photosynthetic pigment contents decrease during dehydration.This may due to rapid repairing mechanism of internal structure in cell.The photosynthetic pigments can completely recover after rehydration,which indicates the change of photosynthetic pigments of syntrichia caninervis Mitt.is reversible during the alternation of dehydration and rehydration.

关 键 词：生物结皮 齿肋赤藓 光合色素 叶绿体 脱水 

分 类 号：Q945.1[生物学—植物学]