高山植物短管兔儿草光合作用特性及其对冰冻胁迫的反应

Photosynthesis in Alpine Plant Lagotis brevituba and Its Response to Freezing Stress

短管兔儿草为典型的高山植物 ,具较强的光合能力 ,但光合效率较低。叶片具有发达的通气贮气组织 ;栅栏组织发达 ,叶绿体基粒片层较少。短管兔儿草光合作用特性易受生长环境因素的影响。低温胁迫使短管兔儿草光合速率、光合量子产额降低。低温下的光照加剧了光合作用受抑制的程度。本研究表明 ,短管兔儿草具较强的抗冻能力 。

Lagotis brevituba , a typical alpine plant grown on Daban mountain(EL.4000 m),has higher photosynthetic capacity but lower quantum yield efficiency. The leaves of Lagotis brevituba possess well_developed palisade tissue, large intercellular spaces. The chloroplast structure is special,it has less grana. The special tissue and cell structure is the basis of the photosynthetic characteristics in Lagotis brevituba . The photosynthetic apparent quantum yeild of Lagotis brevituba grown in the culture room (PAR:60～70 μmol·m -2 ·s -1 ; mean day/night temperature:15/10 ℃) was higher than that grown in the green house (PAR: highest 1?250 μmol·m -2 ·s -1 ;mean day/night temperature:24/13 ℃),whereas the photosynthetic rate and Hill reaction rate were the opposite. Exposure of Lagotis brevituba to freezing stress resulted in declines of photosynthetic rate and apparent quantum yeild.The freezing stress was more inhibitive to the photosynthesis under light (90～100 μmol·m -2 ·s -1 ) than under the dark . Our experimental results indicate that Lagotis brevituba might possess particular freezing resistant mechanism and be a good plant for isolation and screening of freezing resistant genes.