幼穗分化期喷施细胞分裂素(CTK)对水稻穗部性状及株型性状的影响

Effects of Cytokinins Used at Panicle Differentiation Stage on Panicle Traits and Plant Type Traits of Rice

以6个水稻品种为试验材料,分别在幼穗分化的苞分化期(T1)、枝梗分化期(T2)、颖花分化期(T3)、花粉母细胞形成及减数分裂期(T4)和花粉充实完成期(T5)喷施低浓度(C1,5mg/L)、中浓度(C2,10mg/L)、高浓度(C3,20mg/L)的细胞分裂素(cytokinins,CTK),研究其对水稻穗部性状及株型性状的影响。结果表明,幼穗分化的不同时期喷施不同浓度的CTK后,穗长、二次枝梗结实率和穗结实率极显著高于对照,不同浓度CTK处理间差异不显著。穗粒数以低浓度CTK处理最高,其他处理与对照差异不显著。喷施CTK可极显著或显著降低千粒重(包括一次和二次枝梗千粒重)和着粒密度。幼穗分化期喷施不同浓度CTK后,剑叶基角、倒二叶基角、倒三叶基角、倒二叶长、倒三叶长和倒三节长极显著高于对照。在幼穗分化的不同时期喷施CTK后,对穗长的促进效果T1时期喷施极显著高于后4个时期喷施,对穗粒数的促进效果处理T1>T5>T4>T2>T3,对结实率的促进效果以T4时期施用最为明显,T3时期施用着粒密度的降幅最大。CTK的施用浓度与施用时期间具有互作效应,针对不同穗部性状的调控效果,确定最佳的施用浓度与施用时期组合。

Six rice cultivars of indica and japonica were used as test materials to study the effects of spraying cytokinin with lower, medium and high concentrations on the panicle traits of rice during panicle differentiation stages, which including bract differentiation stage （T1）, branch differentiation stage （T2）, spikelet primordium differentiation stage （T3）, pollen mother cell formation and meiosis stage （T4）, pollen filling stage （T5）. Panicle traits of indica and japonica rice in response to exogenous hormone were investigated to determine the optimal spraying stages and concentrations of hormone for regulating panicle traits and rice plant types. The terminal goal was to provide a theoretical basis and reference for the application of hormone production by way of regulation of rice panicle traits and plant type traits. The results were showed as follows： Panicle length and seed setting rate of secondary branch and seed setting rate were extremely significantly higher than that of control, but the differences between different other concentrations of CTK were not significant. Grain number with low concentrations used were higher than that of control, but those under other treatments was not significantly different. Grains weight and grains density fell significantly after applying CTK and flag leaf angle, top second leaf angle, top third leaf angle, top third internode length, flag leaf length, top second leaf width and top third leaf width were extremely significantly higher than that of control. After spraying CTK at different periods of panicle differentiation, the effects of promoting panicle length were bract differentiation stage （T1） extremely significantly higher than that at other stages. The effects of promoting grain number were TI〉T5〉T4〉T2〉T3. The effect of promoting panicle seed setting rate were more obvious at pollen mother cell formation and meiosis stage （T4）, the more obvious the effect of grains density decreased was at spikelet primordium differentiation stage （T3）. There was interaction effect between the spraying periods and concentrations. We made sure the best combination of spraying periods and concentrations aimed at regulating effect of different panicle traits.