摘要
分布于青海高原海拔 40 0 0m高山的唐古特红景天有很强的抗冻能力 ,其叶片半致死温度可达 - 2 6 .5℃ .在北京地区夏季 (7月 )驯化 2 0d后 ,长出新叶片的半致死温度升高为 - 15 .5℃ .光镜组织化学切片显示 ,在唐古特红景天叶片中 ,特别是维管组织周围 ,存在多糖、蛋白质或糖蛋白含量丰富的粘液细胞 ;高温驯化后长出的新叶片这种粘液细胞明显减少或消失 .电镜细胞化学研究揭示 ,在细胞壁外层及细胞间隙中分布着明显的糖蛋白 ,在北京地区驯化 2 0d的唐古特红景天叶片中这种糖蛋白明显减少 .因此推测 ,粘液细胞和叶肉细胞表面的糖蛋白层 ,对唐古特红景天抗冻能力可能起着重要的作用 .图版 1图 2参 2
Rhodiola algida var. tangutica,a alpine plant growing at the snowline of Daban Mountain(h alt=4 000 m)on Qinghai Plateau,is freezing tolerant. Its lethal temperature is -26.5 ℃. After acclimatized for 20 d in summer(from July 6 to July 26)of Beijing,the new emerging leaves could only survive above -15.5 ℃. The results by photomicroscope showed that mucilage cells with high proteins and polysaccharide(or may be glycoprotein)content could be found in the leaves,especially around vascular tissues. Furthermore,cytochemical localization of glycoproteins at the mesophyll cell surfaces and in the intercellular spaces of the leaves after stained with Ruthenium Red was observed by electron transmission microscope. However,after summer acclimation in Beijing mucilage cells could not be observed and the thickness of glycoproteins at mesophyll cell surface of new emerging leaves reduced. Spaces around mucilage cells(vascular tissues)and intercellular spaces surrounded by glycoproteins at cell surface might be the primary sites of ice nucleation when the plant was subjected to freezing stress,possibly avoiding ice formation in the cells and protecting them from freezing injury. Plate 1, Fig 2, Ref 20
出处
《应用与环境生物学报》
CAS
CSCD
2003年第1期16-20,共5页
Chinese Journal of Applied and Environmental Biology
基金
国家自然科学基金 (3980 0 1 1 8
30 2 71 0 67)
霍英东青年教师基金(71 0 30 )
教育部高等学校骨干教师资助计划项目 (650 530 )资助~~
关键词
唐古特红景天
粘液细胞
糖蛋白
抗冻能力
Rhodiola algida var. tangutica
mucilage cells
glycoprotein
freezing tolerance
