麦棉两熟种植模式对棉仁脂肪及蛋白质代谢的影响

摘要

To provide a theoretical basis for improving the quality of cottonseed under the condition of stabilizing the cotton yield and quality in wheat-cotton double cropping region of China, we studied the effects of the cropping system on fat and protein metabolism of cotton embryo. Field experiments were conducted in 2012 and 2013 at the cotton experimental station of Dafeng City, Jiangsu province, China, using cotton cultivars Siza 3 (mid-late maturity) and CCRI50 (early maturity) with four cropping systems monocropping cotton (CK) as control, and three wheat-cotton double cropping systems were intercropped cotton (IC), transplanted cotton (TC) and direct-seeded cotton (DC). The accumulation of cotton embryo fat and protein, and key enzyme ac-tivities as well as their correlation were measured. The results showed that cotton embryo fat content of the double-cropped cotton was lower than that of CK, with the order of IC>TC>DC. Besides, the cotton embryo protein content of IC, TC was higher than that of CK, however, that of DC was lower than that of CK. Moreover, the contents of cotton embryo fat and protein were higher in CCRI50 than in Siza 3. The double-cropped cotton had lower phosphatidate phosphatase (PPase) and glucose-6-phosphate de-hydrogenase (G6PDH) but higher phosphoenolpyruvate carboxylase (PEPC) activities, compared with CK. Furthermore, the ac-tivities of glutamine synthetase (GS) and glutamate synthase (GOGAT) of IC and TC were higher than those of CK, however, those of DC were lower. Moreover, the activities of PPase, G6PDH, GS and GOGAT were higher in CCRI50 than in Siza 3, but the PEPC activity had opposite trend between them. The content of cotton embryo fat was significantly and positively correlated with PPase and G6PDH activities, and significantly and negatively correlated with PEPC activity. In addition, the content of cot-ton embryo protein was significantly and positively correlated with G6PDH, GS and GOGAT activities. In summary, wheat-cotton intercropping system with mid-maturity cotton cultivars should be utilized to increase the quality of cottonseed on the basis of the stable cotton yield and quality in wheat–cotton region double cropping of China.%研究麦棉两熟种植模式影响棉仁脂肪及蛋白质代谢机制,可为我国麦棉两熟棉区在稳定棉花产量和品质的基础上提高棉籽品质提供理论依据。试验于2012年和2013年在江苏省大丰市稻麦原种场进行,以泗杂3号(中晚熟品种)和中棉所50(早熟品种)棉花品种为材料,以单作棉为对照(CK),设置棉花生产上常用的麦套移栽棉(IC)、麦后移栽棉(TC)和麦后直播棉(DC)麦棉种植模式,研究麦棉两熟不同种植模式对棉仁脂肪和蛋白质的累积动态、关键酶活性及其相互关系的影响。结果表明：(1)两熟棉棉仁脂肪含量皆较CK低, IC、TC和DC呈依次下降的趋势； IC和TC棉仁蛋白质含量皆高于CK, DC低于CK；中棉所50棉仁脂肪和蛋白质含量均略高于泗杂3号。(2)两熟棉棉仁磷脂酸磷酸酯酶(PPase)和6-磷酸葡萄糖脱氢酶(G6PDH)活性低于CK,丙酮酸羧化酶(PEPC)活性高于CK； IC、TC棉仁谷氨酰胺合成酶(GS)和谷氨酸合酶(GOGAT)活性高于CK, DC低于CK；中棉所50棉仁具有较高的PPase、G6PDH、GS和GOGAT活性, PEPC活性稍低于泗杂3号。(3)棉仁最终脂肪含量与棉仁代谢过程中PPase、G6PDH活性呈极显著正相关,与PEPC活性呈极显著负相关；棉仁最终蛋白质含量与G6PDH活性及GS、GOGAT活性分别呈显著和极显著正相关。总之,在我国麦棉两熟棉区选择应用中熟棉花品种、麦套移栽方式可以在稳定棉花产量和品质的基础上提高棉籽品质。