2个荔枝品种体胚发生过程中糖含量及相关酶活性变化

为研究糖代谢在荔枝体胚发生过程中的作用,将‘大丁香’和‘新球蜜荔’胚性愈伤组织接种在TD培养基上,并将‘新球蜜荔’接种在TX培养基上,对比体胚诱导过程中3种胚性培养物之间淀粉、蔗糖等糖组分及其代谢相关酶活性变化,以期从糖代谢方面找出影响荔枝体胚发生效率差异的关键因素。结果表明:在体胚发生过程中,‘新球蜜荔’在2种培养基上的淀粉含量都低于‘大丁香’;三者的葡萄糖与果糖含量变化相似,但‘大丁香’都高于‘新球蜜荔’,而‘新球蜜荔’的蔗糖含量则高于‘大丁香’;‘新球蜜荔’的淀粉酶、β-淀粉酶活性都高于‘大丁香’,而α-淀粉酶活性相似。‘新球蜜荔’的蔗糖合酶及在TD培养基上的酸性转化酶活性高于‘大丁香’,但中性转化酶活性是以‘大丁香’偏高,且‘新球蜜荔’在TX培养基上也以中性转化酶为主。由此‘新球蜜荔’通过淀粉酶、蔗糖合酶及转化酶将淀粉转化成蔗糖为体胚发生提供物质能量,而高活性的中性转化酶与低活性的淀粉酶,使‘大丁香’的蔗糖没有得到积累,使其体胚发生效率低于‘新球蜜荔’。

Changes of Sugar Contents and Related Enzyme Activities During Somatic Embryogenesis of Two Lychee Varieties

In order to investigate the effect of sugar metabolism on the somatic embryogenesis of litchi, embryonic callus of ‘Dadingxiang’ and ‘Xinqiumili’ were inoculated on TD medium, respectively, and the embryonic callus of ‘Xinqiumili’ was inoculated on TX medium. Contents of starch, sucrose and other sugar components and activities of the metabolism-related enzymes were compared among the three embryonic cultures. The results showed that starch content on TD and TX medium in ‘Xinqiumili’ were lower than that in ‘Dadingxiang’ during somatic embryogenesis. All the glucose and fructose content were similar, but glucose and fructose contents in ‘Dadingxiang’ was higher than that in ‘Xinqiumili’, while sucrose content in ‘Xinqiumili’ was higher than that in ‘Dadingxiang’. The activity of amylase and β-amylase in ‘Xinqiumili’ were higher than that in ‘Dadingxiang’, but the α-amylase activity in ‘Xinqiumili’ and ‘Dadingxiang’ were similar. The activity of sucrose synthase and acid invertase on TD medium in ‘Xinqiumili’ were higher than that in ‘Dadingxiang’, but neutral invertase activity in ‘Dadingxiang’ was higher than that in ‘Xinqiumili’, and also the dominant by neutral invertase on TX medium in ‘Xinqiumili’. Through converted the starch into the sucrose by amylase, sucrose synthase and invertase in ‘Xinqiumili’ was provided material energy for somatic embryogenesis, while high neutral invertase activity and low amylase activity in ‘Dadingxiang’ can not accumulation of sucrose, maked the efficiency of somatic embryogenesis in ‘Dadingxiang’ was lower than that in ‘Xinqiumili’.