小麦颖果发育和萌发过程中盾片的结构特征

Structure Characteristics of Scutellum during Wheat Caryopsis Development and Germination

为了进一步明确小麦颖果发育和萌发过程中盾片的结构特征,以扬麦13为材料,采用超薄切片、显微和超微观察及Image-pro Plus软件图像分析等技术,研究了小麦盾片在颖果发育及萌发过程中的结构变化。结果表明,花后16d,颖果靠近胚乳的胚周缘细胞由外到内分别分化为盾片上皮细胞和盾片薄壁细胞。在颖果发育过程中,盾片上皮细胞形态由不规则形转变为细长形,数目逐渐增加,面积逐渐减小。盾片上皮细胞中淀粉粒不断降解,颈部盾片上皮细胞呈细长形,而底部细胞呈多边形和椭圆形。盾片薄壁细胞淀粉粒不断增多,体积变大。花后16~20d细胞液泡化,积累脂质体和植酸钙镁颗粒,细胞核中核染色质明显降解。在萌发过程中,盾片上皮细胞由不规则形和多边形向圆形转变,细胞的数目先减少后增加,面积先增加后呈减小趋势。薄壁细胞内淀粉体不断变形、塌陷并逐渐降解,蛋白体发生解体,而脂质体先降解而后又重新合成。由以上结果说明,小麦盾片具有吸收转运养分、贮藏养分及保护胚等功能。

In this paper,Yangmai 13 was used to investigate the changes of wheat scutellum structure during caryopsis development and germination,with resin slice,microstructural and ultrastructural observation and Image-pro Plus soft.Based on the structural observation,scutellum functions for seed development and germination were further analyzed.The main results were as follows：The periphery cells near the endosperm differentiated into scutellar epithelium and parenchyma respectively from outside to inside at 16 days after anthesis（DAA）;During caryopsis development,the epithelial cells of scutellum changed from irregular into slender shape,with increased cell number but decreased cell area.Starch granule in cells also degraded gradually.The epithelial cells in neck scutellum are long and thin while the cells at bottom scutellum are polygon and ellipse.Meanwhile,the number of starch granules in the parenchyma cells increases and the volume becomes large.From 16 to 20DAA,parenchyma cells were vacuolated and lipid bodies and phytinparticles were accumulated,and the nuclear chromatin in nuclear degraded distinctly.In the process of caryopsis germination,the scutellum epithe-lial cells changed from irregular and polygonal into round shape,with cell decreased first and then increased,but the cell area increased first and then decreased.Starch granules of the parenchyma cells were deformed,collapsed and degraded gradually.The protein body was disassembled but the lipid bodies were degraded first and then synthesized again.The results indicated that wheat scutellum has many functions,e.g.transporting nutrients,storaging nutrients and protecting embryo.