盐胁迫下粳稻品种南粳9108分蘖特性及其与群体生产力的关系

旨在明确盐胁迫下水稻分蘖发生与成穗规律及其优势叶位,为沿海滩涂水稻高产栽培的分蘖合理利用与调控提供依据。以江苏沿海滩涂大面积种植的常规粳稻南粳9108为试材,设置对照(盐浓度0)、中盐(盐浓度0.15%)和高盐(盐浓度0.3%)环境,比较研究盐逆境下水稻分蘖发生与成穗特性及其对群体产量的贡献。结果表明,对照、中盐和高盐处理的两年平均产量(t hm–2)分别为9.7、7.4和4.2;中盐和高盐处理的穗数、每穗粒数、结实率和千粒重均显著低于对照。与对照相比,中盐和高盐处理下拔节、抽穗和成熟期群体茎蘖数和成穗率均较低。对照的分蘖利用以一次分蘖和二次分蘖为主,一次分蘖发生在第3至第7叶位,第4至第6叶位是分蘖发生与成穗的优势叶位,二次分蘖则以1/4和1/5蘖位优势较强;盐胁迫的分蘖利用以一次分蘖为主,第4至第6叶位是分蘖发生与成穗的优势叶位。盐胁迫下各蘖位的穗长、每穗粒数、着粒密度、一次枝粳数及粒数、二次枝粳数及粒数均低于对照。与对照相比,盐胁迫下水稻单株成穗数少、个体和群体生长协调性差、穗型小,最终单株和群体产量低。

Tillering characteristics and its relationships with population productivity of japonica rice Nanjing 9108 under salinity stress

This study was conducted to clarify the characteristics for occurrence of rice tillers, its dominant leaf positions, and panicle formation under salinity stress, and to provide a basis for the rational utilization and regulation of rice tillers for high-yield cultivation methods in tidal flat area. Conventional japonica rice Nanjing 9108 was used with three salinity treatments, namely, Control (CK, 0 salt concentration), Medium-salinity stress (MS, 0.15% salt concentration), and high-salinity stress (HS, 0.3% salt concentration) to compare the tillering and panicle formation characteristics and its contribution to population yield under salinity stress. As a result, the average yields (t hm^-2) of CK, MS, and HS were 9.7, 7.4, and 4.2 across two years, respectively; the number of panicles, spikelets per panicle, percentage of filled grains, and 1000-grain weight in MS and HS treatments were significantly lower than those in CK. Compared with CK, the number of tillers at jointing, heading, and maturity and percentage of productive tillers in MS and HS treatments were decreased. For CK, the primary tillers emerged from the 3rd leaf to 7th leaf on the main stem, with higher tiller emerging rate and more panicles from the 4th leaf to 6th leaf among them, and secondary tillers mainly emerged and earbeared from 1/4 and 1/5 tiller position; as for MS and HS, tillers are mainly primary ones emerging from the 4th to 6th leaf as the dominant position for the tiller occurrence and earbearing. The mean value of panicle length, total grains, grain density, and number of grains and its total grains on the primary and secondary branches in MS and HS treatments were both lower than those in CK. Our results suggest that, salinity stress caused lower number of panicles per plant, inferior growth of individuals and populations, smaller panicle types, and finally lower grain yield.