甘蓝型油菜幼苗显微组织结构与抗寒性的关系

摘要

In this study,the relationship between microstructure and cold resistance of rapeseed (Brassica napus)was elucidated.The seedlings of two cold-resistant materials and two cold-sensitive materials of Brassica napus were taken as the experimental materials.And then the paraffin sectioning method was taken to make sectioning paraffin blocks of leaves and stems.The microstructure of leaves and stems was observed and photographed by optical microscope.Finally,the differences and similarities of microstructure of each same organ were compared and analyzed.The results showed there was no significant difference among stem microstructure of each material at different temperature and different periods of low temperature.At room temperature,the identification and boundary clarity of each tissue of the leaf and main vein microstructure in cold-sensitive materials were better than those in cold-sensitive materials,but the cell wall thickness of parenchyma cell around vascular bundle sheath of the main vein microstructure in cold-resistant materials was thinner than that in cold-sensitive materials.Under-2 ℃ stress,the arrangement directions of each tissue of leaves anatomical structure in cold-sensitive materials were messier than that in cold-resistant materials.While the treating time was prolonged,compared with cold-sensitive materials,the number and size of intercellular space of leaves in cold-resistant materials increased significantly.In conclusion,the leaves were the key organ owning perception and signal transduction of low temperature stress.The identification and boundary clarity of each tissue of the leaf and main vein microstructure,and the cell wall thickness of parenchyma cell around vascular bundle sheath of the main vein microstructure can be used as reference-criteria to evaluate the cold resistance of rapeseed.%为研究甘蓝型油菜显微组织结构与其抗寒性的关系,采用石蜡切片法对不同温度和低温胁迫不同时段下的2份抗寒型及2份寒敏感型甘蓝型油菜材料幼苗叶片与茎进行制片,再利用光学显微镜观察叶片与茎的显微组织结构并拍照,进而比较分析各同类组织结构间的异同.结果表明,不同温度和低温胁迫不同时段下,各材料幼茎解剖结构间无明显差异;常温下,抗寒材料叶片叶肉及主脉显微结构各组织间的辨识度与界限清晰度优于寒敏感材料,抗寒材料主脉显微结构中维管束鞘外围薄壁细胞的细胞壁厚度小于寒敏感材料;-2℃胁迫下,寒敏感材料叶片叶肉各组织的排列较抗寒型材料更为杂乱无章,随着胁迫时间的延长,抗寒材料叶肉细胞间隙较寒敏感材料有显著增多增大趋势.可见,叶片是油菜感知低温逆境胁迫及传导胁迫信号的主要器官;叶片叶肉与主脉显微结构中各组织间的辨识度、界限清晰度以及主脉维管束鞘外围薄壁细胞的细胞壁厚度可作为评判油菜抗寒性强弱的参考指标.