抗赖氨酸加苏氨酸莲体细胞变异体的筛选

Selection of somaclonal variants of lotus ( Nelumbo nucifera Gaertn.) by lysine plus threoine stressing

对籽莲红花建莲（Ｎｅｌｕｍｂｏｎｕｃｉｆｅｒａｃｖ．Ｈｏｎｇｈｕａｊｉａｎｌｉａｎ）和白心湘莲（Ｎ．ｎｕｃｉｆｅｒａｃｖ．Ｂａｉｘｉｎｘｉａｎｇｌｉａｎ）杂交而成的幼胚的子叶、胚轴及幼胚叶（芽）形成的愈伤组织，施以赖氨酸加苏氨酸胁迫培养３０天，从中筛选出抗性愈伤组织并形成再生植株。低浓度的赖氨酸加苏氨酸促进愈伤组织的生长，而高浓度的赖氨酸加苏氨酸则抑制愈伤组织生长，直至具有致死作用，这种致死作用是因为高浓度的赖氨酸加苏氨酸抑制了天冬氨酸合成途径中的天冬氨酸激酶和高丝氨酸脱氢酶造成的，细胞发生变异后对赖氨酸和苏氨酸产生了抗性，即与天冬氨酸合成途径有关的氨基酸增加。抗性愈伤组织与未胁迫的愈伤组织的氨基酸测定表明，在总计１７种氨基酸中，抗性愈伤组织有１４种氨基酸含量超过原始愈伤组织，１种持平，２种不及原始愈伤组织。再生抗性植株的莲籽氨基酸测定显示，在１７种氨基酸中，有１２种超过母本红花建莲，１５种超过父本白心湘莲。

Callus induced from young embryos hybrided by Nelumbo nucifera cv. Honghuajianlian × N. nucifera cv. Baixinxianglian were stressed by lysine plus threoine for 30 days. Resistant callus had been selected in vitro and regenerated into plants. Results showed that low concentration of lysine plus threoine could promote the growth of callus, whereas high concentration prohibited their growth, even lethal to callus. Determination of amino acids of resistant callus showed that of all 17 amino acids, 14 more than, 1 equal to and 2 less than those in normal callus. Amino acid analysis of seeds of variant indicated that of all 17 amino acids, 12 in variant was more than in N. nucifera cv. Honghuajianlian and 15 in them was more than those in N. nucifera cv. Baixinxianglian.