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2005—2006年生长季,以小麦强筋品种藁城8901和弱筋品种豫麦50为材料,研究了灌浆期籽粒和旗叶氮代谢底物含量与相关酶活性变化、蔗糖淀粉合成相关酶活性及籽粒淀粉积累特征,分析了氮代谢与籽粒淀粉积累的关系。结果表明,旗叶蔗糖合酶(SS)和磷酸蔗糖合酶(SPS)、籽粒腺苷二磷酸葡萄糖焦磷酸化酶(AGPP)、可溶性淀粉合酶(SSS)、束缚态淀粉合酶(GBSS)和淀粉分支酶(SBE)活性均呈单峰曲线变化。两品种比较,除AGPP活性峰值豫麦50低于藁城8901外,其他酶活性峰值均是豫麦50高于藁城8901。相关分析表明,藁城8901支链淀粉积累速率与SS、SPS、AGPP和SBE活性呈极显著正相关,相关系数分别为0.9377**、0.8857**、0.6489**和0.5980**;直链淀粉积累速率与SS、SPS活性呈极显著正相关,相关系数分别为0.7616**和0.7750**。豫麦50支链淀粉积累速率与SS、SPS、AGPP、GBSS和SBE活性呈极显著或显著正相关,相关系数分别为0.8182**、0.6762**、0.7028**、0.8749**和0.5433*;直链淀粉积累速率与SS、SPS和SBE活性呈极显著正相关,相关系数分别为0.8528**、0.8428**和0.8603**。两品种硝酸还原酶(NR)、谷氨酰胺合成酶(GS)活性在开花后逐渐降低,且藁城8901的NR活性一直高于豫麦50。硝态氮和氨态氮含量与NR、GS活性呈极显著正相关;藁城8901的NR、GS活性与SS、SPS活性呈显著负相关,而豫麦50只有GS与SPS达显著负相关(r=-0.5212*)。上述结果表明,不同品质类型小麦籽粒淀粉合成积累受氮代谢相关酶活性的影响,藁城8901较高的NR活性抑制与蔗糖合成有关酶SS、SPS的活性,导致淀粉合成积累速率降低。由此可见,SPS/NR比值对淀粉合成具有重要调节作用。
During the growing season from 2005 to 2006, with the strong gluten varieties Tancheng 8901 and the weak gluten varieties Yumai 50 as materials, the contents of nitrogen metabolism substrates and related enzymes and the activities of enzymes involved in the synthesis of sucrose starch during grain filling and flag leaf senescence And the characteristics of starch accumulation in grains, the relationship between nitrogen metabolism and grain starch accumulation was analyzed. The results showed that the activities of flag leaf sucrose synthase (SS), sucrose phosphate synthase (SPS), grain glucide diphosphate glucose pyrophosphorylase (AGPP), soluble starch synthase (SSS), bound starch synthase And starch branching enzyme (SBE) activity showed a single peak curve changes. In comparison with the two cultivars, except Yumai 50 with lower AGPP activity than Tancheng 8901, the highest activities of other enzymes were Yumai 50 higher than Tancheng 8901. Correlation analysis showed that the accumulation rate of amylose in Tancheng 8901 had a significant positive correlation with the activity of SS, SPS, AGPP and SBE, the correlation coefficients were 0.9377 **, 0.8857 **, 0.6489 ** and 0.5980 **, respectively. Amylose There was a significant positive correlation between accumulation rate and SS and SPS activities, with correlation coefficients of 0.7616 ** and 0.7750 **, respectively. The amylose accumulation rate of Yumai 50 had a significant or significant positive correlation with SS, SPS, AGPP, GBSS and SBE activities, and the correlation coefficients were 0.8182 **, 0.6762 **, 0.7028 **, 0.8749 ** and 0.5433 *, respectively. The amylose accumulation rate had a significant positive correlation with SS, SPS and SBE activities, and the correlation coefficients were 0.8528 **, 0.8428 ** and 0.8603 **, respectively. NR and GS activities of two cultivars decreased gradually after anthesis, and NR activity of Tancheng 8901 was always higher than that of Yumai 50. There was a significant positive correlation between nitrate nitrogen and ammonia nitrogen content and NR and GS activities. There was a significant negative correlation between NR and GS activities and the activity of SS and SPS in Tancheng 8901, but significant negative correlation between GS and SPS in Yumai 50 r = -0.5212 *). The above results indicated that the accumulation of starch in different quality wheat varieties was affected by the activities of enzymes related to nitrogen metabolism. The higher NR activity in Tancheng 8901 inhibited the activities of enzymes SS and SPS related to sucrose synthesis, resulting in a decrease in the accumulation rate of starch synthesis. Thus, SPS / NR ratio of starch synthesis has an important regulatory role.