摘要
用透射电子显微技术研究了西瓜叶片小叶脉,结果表明,小叶脉是由大型维管束鞘细胞包围的维管束,维管束呈现大的头部和线形的柄部,柄部是单列细胞的木质部,由维管薄壁细胞和导管分子组成;头部是韧皮部,由维管薄壁细胞、伴胞和筛管分子组成。同一小叶脉内常见有超微结构特征显著不同的两种伴胞:一种伴胞体积小,与维管束鞘细胞接触面较小或不接触,细胞内有大液泡,细胞壁上没有胞间连丝或只有少数不分枝的胞间连丝,这种伴胞为2a型;另一种伴胞体积大,通常位于韧皮部两翼,不含大液泡而含大量小泡,与维管束鞘细胞接触面较大,接触面上有大量具分枝的胞间连丝,分枝部分比未分枝部分直径小,这种伴胞为中间细胞类型。显然,西瓜是小叶脉内兼具两种类型伴胞的植物。
Minor veins in watermelon leaf blades were studied by transmission electron microscopy. The minor vein was a vascular bundle surrounded by large bundle sheath cells. Xylem parenchyma cells and vessel elements were arranged in a linear form, whereas phloem parenchyma cells, companion cells, and sieve elements aggregated to form the head. Two types of companion cells can be distinguished based on their ultrastructural features. One type （2a type） was smaller, contains larger vacuoles, and possessed few plasmodesmata, which did not branch. The other type was located on both sides of the phloem and contacted the vascular bundle sheath with a large area. This type was typically characterized by the presence of abundant vesicles in cytoplasm and numerous branched plasmodesmata across its walls. These features define the cells as intermediary cells. Therefore, it was proposed that watermelon belongs to plants that possess two types of companion cells in the same minor veins.
出处
《植物科学学报》
CAS
CSCD
北大核心
2013年第2期186-190,共5页
Plant Science Journal
基金
山东省自然科学基金(ZR2011CL002)
临沂大学科研计划项目(XH09104)
关键词
西瓜
小叶脉
2a型伴胞
中间细胞
Watermelon
Leaf minor vein
2a type companion cell
Intermediary cell
