甜高粱茎秆不同节间糖分累积与相关酶活性的变化

Sugar Metabolism and Change of Related Activities of Enzymes in Internodes of Sweet Sorghum

为了进一步了解甜高粱茎秆糖分代谢的规律,利用高效液相色谱等方法测定了考利、拉马达和MN-2747等3个甜高粱品种成熟期6个节间果糖、葡萄糖和蔗糖含量以及中性转化酶(NI)、可溶性酸性转化酶(SAI)、蔗糖磷酸合成酶(SPS)和蔗糖合成酶(SS)的酶活性,并对其变化规律和相关性进行了分析。结果表明:不同品种间,果糖、葡萄糖和蔗糖含量变化范围较大,分别为2.32～4.34mg/g、2.30～4.14mg/g和35.92～95.92mg/g。随着节间的变化,3个品种果糖和葡萄糖均呈现"U"型变化趋势,而蔗糖无明显的变化规律,只是略有增高的趋势。3个品种成熟期茎秆中NI、SAI、SPS和SS酶活性普遍较低,随着节间的提高均呈现降低的趋势。节间蔗糖含量与SAI酶活性呈显著负相关(R=-0.71,P<0.01),与NI、SPS和SS酶活性无明显相关性。SAI可能为甜高粱茎秆糖分代谢的关键调控酶。

In order to understand sugar metabolism in stalk of the sweet sorghum, content of glucose, fructose and sucrose and the activities of neutral invertase （NI）, soluble acid invertase （SAI）, sucrose phosphate synthase （SPS） and sucrose synthase （SS）from six internodes of Cowley, Ramada and MN-2747 sweet sorghum （Sorghum bicolor（ L. ）Moench）cultivars were assayed. The results showed that the content of fructose,glucose and sucrose were significantly different within three cuhivars,were 2.32 -4.34mg/g,2.30 -4. 14mg/g and 35.92 -95.92mg/g respectively. Content of fructose and glucose showed a ＂ U＂ type trend and content of sucrose had no significant changes,only a slight increase, with the internodes number. Enzyme activities of NI, SAI, SPS and SS in mature stem were generally low,and showed a decreasing trend with the internodes number. It was negatively correlated between sucrose content and SAI activity（ R = -0.71 ） , and no relationship with NI, SPS and SS activity in individual internodes. SAI might be a key enzyme controlling sugar metabolism in the sweet sorghum stalk.