【摘要】 为研究甘蔗叶片中蔗糖代谢酶活性及糖含量变化，解析甘蔗“源-库”糖分积累调控机制，分别对分蘖期、拔节期、成熟期‘新台糖22号’甘蔗成熟叶片中蔗糖磷酸合成酶、蔗糖合成酶、酸性转化酶、中性转化酶的活性及叶片中蔗糖和还原糖含量采用比色法进行测定。结果表明随着茎秆生长及糖分积累，甘蔗叶片中蔗糖磷酸合成酶活性从10.3μmol/(gFW·h)逐渐升高至14.6μmol/(gFW·h),成熟期甘蔗叶片中蔗糖磷酸合成酶活性显著降低至5.3μmol/(gFW·h);甘蔗叶片中蔗糖合成酶在茎秆中糖分积累时蔗糖合成活性由14.0μmol/(gFW·h)降低至9.1μmol/(gFW·h);分蘖期甘蔗叶片中蔗糖转化酶活性介于26.0～30.2μmol/(gFW·h),而成熟期甘蔗叶片中蔗糖转化酶活性显著降低至13.9～16.4μmol/(gFW·h)。甘蔗叶片中蔗糖含量在茎秆中糖分积累时达到最高20.57 mg/gFW;分蘖期甘蔗叶片中还原糖含量2.1 mg/gFW,而拔节期、成熟期甘蔗叶片中还原糖含量分别升高至5.45 mg/gFW和7.15 mg/gFW。甘蔗叶片中蔗糖磷酸合成酶活性与蔗糖含量呈正相关，表明甘蔗叶片中蔗糖磷酸合成酶直接调控蔗糖合成。研究结果表明叶片中蔗糖磷酸合成酶及蔗糖含量积极响应茎秆中糖分积累信号，蔗糖磷酸合成酶是甘蔗“源-库”糖分积累调控的关键作用靶点，进一步解析甘蔗叶片中蔗糖磷酸合成酶调控网络可为甘蔗糖分性状改良提供理论依据。更多还原

【Abstract】 To analyze the changing features of sucrose metabolism enzymes and sugar contents in sugarcane leaves at different growth stages and clarify the “source-sink” sugar accumulation mechanism in sugarcane, the activities of sucrose phosphate synthase(SPS), sucrose synthase(SS), soluble acidic invertase(SAI) and neutral invertase(NI) and sugar contents in mature leaves from ‘ROC22’ sugarcane plants at tillering, elongation and mature growth stages were measured with colorimetric methods. The results showed that the sucrose synthesis activity of SPS were increased from 10.3 μmol/(gFW·h) to 14.6 μmol/(gFW·h) in leaves of sugarcane plants from tillering stage to elongation stage and reached the maximum at the sucrose rapid accumulation stage. The SPS activity in sugarcane leaves was decreased greatly to 5.3 μmol/(gFW·h) in plants at maturation stage. The sucrose synthesis activities of SS in sugarcane leaves were decreased from 14.0 μmol/(gFW·h) to 9.1 μmol/(gFW·h) the plants at the sugar accumulation growth stage. The activities of SAI and NI ranged from 26.0 to 30.2 μmol/(gFW·h) in sugarcane plants at tillering growth stage and decreased to 13.9～16.4 μmol/(gFW·h) at mature stage. The sucrose content reached the highest of 20.57 mg/gFW in sugarcane leaves from plants at sugar accumulation elongation growth stage. The reducing sugar content was 2.1 mg/gFW in leaves at tillering growth stage and increased to 5.45 mg/gFW and 7.15 mg/gFW at elongation and maturation growth stages, respectively. The SPS activity changes were positive correlation with sucrose content changes in leaves of sugarcane plants. It indicated that SPS directly regulated the sucrose content in sugarcane leaves. These results showed that the SPS activity and sucrose content in sugarcane leaves actively responded to the sugar accumulation signals in sugarcane stalks. It indicates that SPS in sugarcane leaves is the key regulation target during “source-sink” sugar synthesis and accumulation. The SPS activity and sucrose content in sugarcane leaves reaches the maximum during sugar rapid accumulation in sugarcane stalks. Further clarifying the molecular network regulating SPS activity in sugarcane leaves will provide theoretical basis for improvement of sugar content in sugarcane.更多还原