水稻低纤维突变体LCM527-1发育理化性质和亚显微结构特征

Physicochemical Properties and Ultra-structure Characteristics of Development Stages of Low Cellulose Mutant LCM527- 1 of Rice

细胞壁是植物细胞水平的重要支撑骨架和体现机械强度的关键结构,其主要成分为纤维素。本研究通过测定水稻茎秆突变体细胞壁理化指标,进行胞壁结构超微观察,研究茎秆低纤维脆性的生化特点以及细胞形态变化,以期阐述水稻低抗折断力、易倒伏的原因。经60Co-γ射线诱变处理和筛选,获得特异性低纤维突变体LCM527-1,其生物学性状表现为茎、叶、鞘、枝梗均具脆性;抗倒伏指数、茎秆密度(鲜重或干重)以及倒1节和倒2节抗折断力均明显降低;茎秆中Ca、K、Mn、Na、Si、Zn等6种重要组成元素也显著减少。与527(CK)相比,突变体LCM527-1在5个生长发育时期(幼苗期、分蘖期、抽穗期、灌浆期和成熟期)的细胞壁主要成分纤维素含量显著降低,次级修饰物半纤维素和木质素增加。超微结构显示突变体LCM527-1茎、叶的厚壁细胞、薄壁细胞等细胞壁变薄,细胞层数减少,填充效果减弱。由此可知,细胞水平的异常是导致该茎秆易折断的主要原因。本研究将为今后水稻茎秆突变体的研究提供支持,同时为抗倒伏工作开展提供新的思路和途径。

Plant cell wall is an important three-dimensional dynamic network to support plant growth and protect cells＇ structure. To elucidate the reasons for low breaking-resistance in the low cellulose mutant,the biochemical traits and morphological changes of cell wall were investigate by analyzing physicochemical properties and the ultra-structure of cell wall in the low cellulose mutant LCM527- 1 which derived from the rice variety 527（ CK） by radiation of^60-γ.LCM527- 1 appeared obvious fragility in leaf,stem and branches during the whole growing stages and exhibited low break-resistance in the field. In comparison with the wild type 527（ CK）,the mutant displayed some changes in the components that involved in assembling the cell wall during five development stages,especially the significant decrease of cellulose. While the content of hemicellulose and lignin was increased. The content of Ca,K,Mn,Na,Si,Zn was all reduced significantly in the rice stem. Ultra-structural features exhibited the different thickness of scler-enchyma and parenchyma of cell walls,which indicated that thinner cell walls and weaker mechanical strength possibly caused by cellulose decreasing,mineral elements reducing and cellular structure deformation. Physicochemical investigation and cellular ultra observation were well displayed the linkage between mechanical strength and chemical components of cell wall.