Photosynthesis and carbohydrate storage and remobilization was investigated during grain filling of winter wheat (Triticumaestivum L., cv. Lumai 22) in sulphur application experiments where the available sulphur (S) content in the soil of 0-20 cmsoil layer was 5.84 mg kg-1. Two levels of S were applied as S0 (0 kg S ha-1) and S1 (67.5 kg S ha-1). The results showed thatnet photosynthetic rate of flag leaf of S1 treatment was significantly higher than S0 treatment, and it increased graduallyfrom anthesis to 35 DAA. Sucrose-phosphate synthase (SPS) activity and sucrose content of S1 treatment were significantlyhigher than those of S0 treatment. The contents of total soluble sugar, sucrose, fructose, glucose, DP3 and DP ≥ 4fructan in stem and sheath of S1 treatment were significantly higher than those of S0 treatment also. The amount of totalsoluble sugar and fructans remobilization from stem and sheath and the starch accumulating rate in grain of S1 treatmentwas significantly higher than those of S0 treatment. It is suggested that sulphur application increase photosynthateremobilization from stem and sheath to grain at later filling stage.
在池栽条件下,研究了施氮量和花后土壤相对含水量对小麦氮代谢特性和子粒蛋白质含量的影响。结果表明,在同一施氮量下,旗叶和子粒硝酸还原酶(NR)和谷氨酰胺合成酶(GS)活性表现为花后土壤相对含水量(Soil relative water content,SRWC)在60%～70%时最高,过低(40%～50%)或过高(80%--90%)均降低NR和GS活性。旗叶蛋白酶活性随土壤相对含水量增加而降低;花后土壤相对含水量过低不利于叶片游离氨基酸含量的提高,过高则前期氨基酸合成少,后期向子粒转运不彻底。子粒游离氨基酸和蛋白质含量也随土壤相对含水量增加而降低;子粒蛋白质积累量以花后土壤相对含水量为60%～70%时最高,过高和过低均不利于子粒蛋白质积累。在同一土壤含水量下,旗叶和子粒NR和GS活性表现为随着施氮量的增加而升高,蛋白酶活性随着施氮量增加而降低;旗叶和子粒游离氨基酸含量、子粒蛋白质含量和积累量随施氮量增加而提高,但施氮量过多。蛋白质积累量增加幅度减小。试验表明,小麦生产中可以通过施用氮肥和控制花后土壤水分含量技术,调节植株氮代谢,提高子粒蛋白质含量。
