赤霉素喷施时期对水稻光温敏核不育系节间伸长和抽穗相关性状的影响

以10个水稻光温敏核不育系为材料,设置不同赤霉素(gibberellin acid 3,GA3)喷施时期处理,研究了GA3喷施时期对不育系节间伸长和抽穗相关性状的影响。结果表明,喷施GA3可促进不育系茎秆各部位节间伸长和植株增高,但对剑叶鞘长没有明显影响;稻穗破口期(穗尖刚露出剑叶鞘)是不育系喷施GA3的适宜时期,此时喷施GA3对促进顶1节间伸长、解除包颈和提高穗粒外露度的效果最好;破口前1d(穗尖距叶枕-3 cm)喷施GA3的效果次之,破口后1 d(穗尖抽出剑叶鞘3 cm)喷施GA3的效果较差;随喷施时期的推迟,中下部节间长和穗高逐渐缩短。对不育系群体而言,抽穗率10%-15%是开始喷施GA3的适宜时期,此时喷施GA3,不育系群体的平均穗粒外露度最高,包颈度最小。

Effects of spraying stage of gibberellin acid 3 on the internode elongation and heading related traits of PTGMS lines in rice

Using 10 photoperiod- and thermo-sensitive genic male sterile (PTGMS) lines in rice as the materials, theeffects of spraying time of gibberellin acid 3 (GA3) were studied on the internode elongation and heading related traits by spraying GA3 at different stages. The results showed that GA3-spraying could elongate the internodes and increase plant height but it couldn't increase the length of flag leaf sheath. The panicle tip emergence stage (PTES), i.e., the time when the panicle tip has just exserted out of flag leaf sheath, was the optimal time for GA3-spraying because spraying GA3 at this time had the best effect on promoting elongation of the first internode from top, relieving panicle enclosure and increasing panicle exsertion degree. The effect of spraying GA3 one day before PTES (with the panicle tip 3 cm under the pulvinus) took second place, and that of spraying GA3 one day after PTES (with the panicle tip exserting 3 cm out of flag leaf sheath) was relatively poor. The length of lower-middle internodes and panicle height shortened gradually with the postponingof GA3-spraying time. It was also found that the stage with 10%-15% of heading panicles, when the GA3-spraying would result in highest panicle exsertion degree and lowest panicle enclosure, was the right time of GA3-spraying for the population of a PTGMS line.