孕穗期干旱胁迫对寒地粳稻干物质积累、转运及产量形成影响

Effect of drought stress at booting stage on dry matter accumulation,transportation and yield formation of cold-region rice

干旱缺水是限制水稻产量主要环境因素之一。为探讨孕穗期干旱胁迫对寒地粳稻干物质积累规律及产量形成影响,选用耐旱型品种东农425和干旱敏感型品种松粳6号为试验材料。通过盆栽结合人工控水方式于孕穗期控制土壤水势至0、-10、-25和-40 k Pa,处理21 d后恢复正常灌溉。研究孕穗期不同程度干旱胁迫对寒地粳稻干物质积累分配转运、产量及产量构成因素影响。结果表明,孕穗期干旱胁迫导致地上部干物质积累量、转运量均随土壤水势降低而下降。成熟期不同器官干物质分配表现为籽粒>茎鞘>叶,茎鞘干物质和源器官干物质分配比例及源/库随干旱程度上升而增加,而籽粒干物质分配比例与其相反。抗旱性强品种在干旱胁迫条件下有较强物质积累优势,贮藏物质转运能力明显高于抗旱性较弱品种。干旱胁迫使枝梗性状下降,对枝梗性状影响表现为二次枝梗>一次枝梗。干旱胁迫下寒地粳稻由于每穴穗数、穗粒数和结实率显著降低造成产量显著下降,降幅随土壤水势降低而逐渐上升。

Water shortage is a main environmental factor that constrains rice production. In order to investigate the effects of drought stress at booting stage on dry matter accumulation and yield formation of cold-region rice, Drought-tolerant cold-region rice variety Dongnong425 and drought- sensitive cold-region rice variety Songjing6 were selected as test materials. Through pot experiment which combined with artificial water control to control soil water potential at booting stage to 0, -10, -25 and-40 kPa, ended with 21 d after treatment. The effects of different drought stress on dry matter accumulation, transportation, partitioning, yield and its components of cold-region rice were studied. Results showed that the drought treatment lead to both the dry matter accumulation of above-ground part and the translocation decreased with the decrease of soil water potential. Dry matter distribution of different organs to grain yield were spike〉stem＋sheath〉leaf in maturity. Dry matter distribution ratios of stem ＋ sheath, total dry matter distribution ratios and source/sink all increased with the enhancement of drought stress, but the dry matter distribution ratios of spike was opposite. Under water stress conditions, the strong drought resistance cultivar had higher dry matter accumulation advantage and reserve matter translocation abilities. The yield of cold-region rice decreased significantly under drought stress, and the amplitude increased with the decrease of soil water potential, the main reason was the significantly decrease of effective panicle numbers and spikelets numbers per panicle. The drought treatment lead to the branch traits decreased and their effects were secondary branch〉primary branch. It indicated that the cut of yield in cold-region rice was because the significant reduction of storage capacity, spikelets per unit area and seed setting percentage caused by low soil water potential.