Relation Between Changes in Ultrastructure and Composition of Cell Wall and Calcium related Physiological Disorder of Chinese Cabbage ( Brassica campestris ssp. pekinensis )
缺钙培养诱导大白菜干烧心发生 ,测定心叶组织细胞壁各成分含量的变化。结果表明 ,随着缺钙天数增加 ,果胶、半纤维素 1(HC1)和纤维素的含量呈平稳上升 ,到缺钙处理后第 2 4天时达到高峰 ,随后急剧下降 ,而半纤维素 2 (HC2 )的含量变化不大 ;醛酸在果胶中的含量逐渐呈下降趋势 ,在HC2中的含量先升后降 ,而在HC1和纤维素中的含量变化不大 ;总糖在HC1和纤维素中的含量呈下降趋势 ,在果胶中的含量先升后降 ,而在HC2中的含量变化不大 ;葡聚糖含量也是先升后降 ,在缺钙处理后第 8天有一高峰值 ;尤其是蛋白质在果胶和纤维素部分中的含量较低且变化不大 ,在HC1中的含量极明显减少 ,而在HC2中的含量却极显著增加。同时 ,细胞壁结构发生相应变化。可见 ,大白菜干烧心的发生与细胞壁结构和功能的变化直接相关It is proposed that the so called “tipburn” sympton in Chinese cabbage is caused by Ca deficiency in inner leaf tissues. The changes in the cell wall structure and its composition were followed during the development of “tipburn” sympton using a hydroponic culture system for Chinese cabbage, in which Ca deficiency treatment was included. During the course of development of Ca deficiency induced, the contents of pectin, hemicellulose portion I(HC1) and cellulose increased steadily until their peaks were reached on the 24th day after treatment, then declined rapidly (Fig.1). In contrast, that of hemicellulose portion II (HC2) was stable during the course (Fig.1). The content of uronic acids decreased in the portions of pectin, rose and then dropped in the portions of HC2, kept constant in the HC1 and cellulose portions (Fig.2). The content of total sugar was decreased in the HC1 and cellulose portions, rose and then declined in the portions of pectin, but seemed to be constant in the portions of HC2 (Fig.3). The content of proteins was low and little changes in the pectin and cellulose portions during the course of Ca deficiency. However, proteins in the portions of HC1 decreased significantly in constrast to the rapid increase in the portions of HC2 (Fig.4). In addition, Ca deficiency resulted in a shift of callose synthesis during the earily days of treatment until day 8 when callose began to decrease. The role of Ca in maintaining cell wall structure and function and its relation to the development of “tipburn” sympton was disscused in connection with these results.国家自然科学基金资助项
