江苏中籼水稻品种演进过程中根系形态生理性状的变化及其与产量的关系

Changes in Morphological and Physiological Traits of Roots and Their Relationships with Grain Yield during the Evolution of Mid-season Indica Rice Cultivars in Jiangsu Province

以江苏省近60年来各阶段具有代表性的13个中熟籼稻品种(含杂交稻组合)为材料,依据品种种植年代结合株型和基因型特点将其分为早期高秆(ET)、矮秆(DC)、半矮秆(SDC)和超级稻(SR)4个类型,研究了中籼水稻品种演进过程中根系形态生理性状的变化及其与产量的关系。结果表明,在各主要生育期,根干重、根重密度、根长、根长密度和根直径随品种演进增加或显著增加。自抽穗期,地上部干物重随品种演进显著增加。在分蘖中期和穗分化始期,超级稻品种的根冠比显著大于其他类型品种,在生育进程中,各类型间无显著差异。在分蘖中期,随品种演进,比根长显著降低,但在生育进程中,各类型间无显著差异。在生长早期和中期,根系氧化力、叶片光合速率、根系总吸收表面积和活跃吸收表面积以及根系伤流液中细胞分裂素(玉米素+玉米素核苷)浓度随品种演进增加或显著增加。随着品种演进产量逐步提高,其原因主要是每穗粒数的增多导致总颖花量的增加。回归分析表明,根干重、根长、根直径、根系氧化力、根系总吸收表面积和根系活跃吸收表面积与产量呈极显著线性正相关关系。说明改善的根系和地上部的生长,促进了现代品种特别是超级稻品种产量的提高。

Roots are involved in acquisition of nutrients and water,synthesis of plant hormones,and anchorage of plants.However,little is known what changes in root physiology and morphology during the evolution of rice cultivars.In this study,13 typical mid-season indica rice cultivars （including hybrid combinations） applied in the production in Jiangsu Province during the last 60 years were used,which were classified into four types of early tall cultivars,dwarf cultivars,semi-dwarf cultivars,and super rice cultivars according to their application times,plant types and genotypes.All the tested cultivars were grown in the field and changes in morphological and physiological traits of roots and their relationships with grain yield during the evolution of cultivars were investigated.Results showed that the root dry weight,root weight density,root length,root length density and root diameter were increased with the evolution of the cultivars at main growth stages.From the heading stage,the shoot dry weight was increased with the evolution of the cultivars.Compared with other cultivars,the root-shoot ratio of super rice cultivars was increased at the mid-tillering and panicle initiation stages,but showed no significant differences among the four types of cultivars at latter growth stages.Specific root length was decreased with the evolution of the cultivars at the mid-tillering stage,and showed no significant differences among the four types of cultivars at other growth stages.The root oxidation activity,leaf photosynthetic rate,total absorbing surface area and active absorbing surface area of root,and the content of cytokinins （zeatin ＋ zeatin riboside） in root bleeding and grain yield were increased with the evolution of the cultivars.Increase in grain yield was attributed mainly to the increase in total number of spikelets,which resulted mainly from a large panicle.Regression analysis showed that the root dry weight,root length,root diameter,root oxidation activity,total absorbing surface area and active absorbing surface area of root very significantly correlated with grain yield.The results suggest that the improved root and shoot growth increases grain yield of the modern cultivars,especially super rice cultivars.