氮肥对水稻节间和叶鞘非结构性碳水化合物积累转运特征的影响

以两优培九和扬稻6号为材料进行盆栽试验,研究低氮(N1)和高氮(N2)处理下水稻主茎上部3个节间和叶鞘非结构性碳水化合物(NSC)的积累转运特征及对氮肥用量的响应。结果表明:1)与N2处理相比,N1处理总体上显著促进灌浆早期两优培九倒2、倒3节间和叶鞘NSC的转运,对扬稻6号的影响差异不明显;N1处理显著增加了扬稻6号上部3个节间及叶鞘和两优培九倒3节间及叶鞘NSC表观转运量,也增加了两品种上部3个节间及叶鞘的NSC(总)表观贡献率。2)两个氮肥处理下,供试品种的叶鞘(两优培九倒3叶鞘除外)NSC转运量和表观贡献率大于节间。3)两优培九倒2、倒3节间及叶鞘NSC表观转运量和贡献率、上部3节间及叶鞘的NSC总转运量与总表观贡献率在两个氮肥处理下均高于扬稻6号。4)N1处理下,两优培九和扬稻6号倒2、倒3节间及叶鞘的转运量分别占总转运量的92%和75%,贡献率分别占91%和76%;而N2处理下两优培九倒2、倒3节间及叶鞘的转运量占90%,扬稻6号倒2、倒3节间则无输出。本研究表明水稻上部3个节间和叶鞘的NSC(总)转运量品种间存在差异,并受施氮量和节/叶位的影响。在水稻高产和减氮栽培中,通过选用适宜品种和优化氮肥管理,增加花前茎鞘NSC积累和花后NSC再分配,对提高水稻产量潜力和氮效率,特别是对花后逆境和减氮条件下产量稳定具有重要意义。

Effects of Nitrogen Application on Accumulation and Translocation of Non structural Carbohydrates in Internodes and Sheaths of Rice

Two indica rice varieties, Liangyoupeijiu (LYP9) and Yangdao 6 (YD6), were grown in pots under low (N1) and high (N2) nitrogen application rates. The accumulation and translocation of non structural carbohydrates (NSC) in the top most three internodes and leaf sheaths of main stems and its contributions to grain yield were investigated. 1) Compared with N2 treatment, N1 treatment enhanced NSC translocation of the second and third internodes and sheaths in LYP9 during the early grain filling stage, and also increased the apparent transferred mass of NSC (ATMNSC) of the three internodes from the top and sheaths in YD6 and the third internode from the top and sheath in LYP9, respectively. However, N1 treatment had no obvious effect on ATMNSC of the top first and second internodes and sheaths in LYP9. Noticeably, N1 treatment increased the apparent contributions of NSC to grain yield (ACNSC) of the three internodes and sheaths in both two varieties. 2) Except the top most third sheath in LYP9, the ATMNSC and ACNSC of sheaths were higher than those of internodes in both two varieties under N1 and N2 treatments. 3) Under N1 and N2 treatments, ATMNSC and ACNSC of the top most second and third internodes and sheaths, and total ATMNSC and ACNSC of the three internodes and sheaths in LYP9 were higher than those in YD6, respectively. 4) Under N1 treatment, the top most second and third internodes and sheaths totally contributed 92% and 91% of total ATMNSC and ACNSCof the three internodes and sheaths in LYP9, and 75% and 76% in YD6. Under N2 treatment,the top most second and third internodes and sheaths totally contributed 90% and 91% in LYP9, and no NSC translocation from the top most second and third internodes and totally accounted for 77% of total ACNSC. Our results indicated that ATMNSC of the three internodes and sheaths showed genotypic variation and depended on internode/sheath, and was affected by N application rate. Optimizing N fertilizer application and selecting suitable rice variety might enhance pre anthesis NSC accumulation and post anthesis NSC translocation, which could further increase rice yield potential and nitrogen use efficiency, especially stability of grain yield under adverse environments and nitrogen fertilizer reducing practice.