沙拐枣属植物同化枝和子叶的解剖学研究

采用石蜡切片技术,对相同生境下的戈壁沙拐枣、柴达木沙拐枣和英吉沙沙拐枣的子叶,及中国特有种柴达木沙拐枣、塔里木沙拐枣、阿拉善沙拐枣和英吉沙沙拐枣同化枝的横切面解剖结构进行观察研究.结果显示:(1)3种沙拐枣子叶均为全栅等面叶;表皮为单层细胞,上下表皮均分布气孔,栅栏组织以内为一圈连续排列的维管束鞘细胞;中脉和小叶脉排列近似M型,包埋于薄壁细胞中.(2)塔里木沙拐枣同化枝的保护组织、栅栏组织较发达,英吉沙沙拐枣同化枝机械组织和输导组织较为发达,阿拉善沙拐枣同化枝的栅栏组织较为发达,相比较柴达木沙拐枣同化枝的保护组织、机械组织和输导组织最不发达.(3)柴达木沙拐枣和英吉沙沙拐枣中子叶与同化枝的横切面各组织分布相似,主要差异为横切面形状、维管束排列方式和机械组织发达程度.研究表明,子叶与同化枝的解剖结构是该属植物在干旱环境下长期适应的结果,解剖结构的差异体现了种间、器官间对相同环境的不同适应策略.

Anatomical Structure of Assimilating Shoots and Cotyledons of Calligonum L.

With the method of paraffin dissection,the transverse anatomic cotyledons of 3 species in Calligonum L.,which are C.gobicum,C.zaidamense and C.yingisaricum,and assimilating shoots structures of 4 Chinese endemic species of Calligonum L.in same habitate,which are C.zaidamense,C.roborovskii,C.alashanicum and C.yingisaricum,have been observed.The results were as follows:(1)Cotyledons of 3 species Calligonum L.are total-palisade,and epidermis cell layers are same.Stomas distribute on both upper and lower epidermis.Inside of palisade tissue is a layer of bundle sheath cell.Distribution of leaf veins shows M in parenchyma cells.(2)Assimilating shoots of C.roborovskii has developed protective and palisade tissue,and C.yingisaricum has developed mechanical and conducting tissue.C.alashanicum has developed palisade tissue.Compare with them,assimilating shoots of C.zaidamense has the least developed protective,mechanical and conducting tissue.(3)Through the observation of C.zaidamense and C.yingisaricum,tissue distribution of cotyledons and assimilating shoots is similar.Main differences are transverse sections figure,distribution and numbers of vascular bundle and the development degree of thick-walled cells.Anatomical structures of cotyledons and assimilating shoots indicate well adaptation to dry areas.In the same dry areas,different species in Calligonum L.and different organs of one species in Calligonum L.have different adaptation strategies.