《植物生理学报》 2013, 49(8): 729-737

水稻不同粒位籽粒脱落酸含量差异及其与籽粒灌浆的关系

董明辉^1,2,*, 顾俊荣¹, 陈培峰¹, 刘腾飞¹, 赵步洪³

¹苏州市农业科学院, 江苏苏州215155; ²扬州大学江苏省作物遗传生理国家重点实验室培育基地, 江苏扬州225009; ³江苏里下河地区农业科学研究所, 江苏扬州225007

通信作者：董明辉；E-mail: mhdong@yzu.edu.cn；Tel: 0512-65382356

摘　要：

选用籼稻‘扬两优6号’和粳稻‘武运粳24号’为材料, 观测不同粒位籽粒灌浆和脱落酸(ABA)含量变化动态及两者的相关关系, 灌浆初期喷施外源ABA验证其对不同粒位籽粒粒重的影响。结果表明: 籽粒粒重增长速率和ABA含量呈单峰曲线; 同枝梗上较早开花的籽粒灌浆启动快, ABA含量与灌浆速率到达最大值的时间较早, 峰值也较高; 灌浆初期, 迟开花籽粒中可溶性糖含量显著高于早开花籽粒, 同化物的供给可能不是限制弱势粒灌浆不良的重要因素; 籽粒灌浆期, ABA含量与籽粒灌浆速率呈极显著正相关, 与最终籽粒粒重在灌浆初期呈显著正相关, 灌浆中后期呈显著负相关; 灌浆始期喷施低浓度ABA对籽粒粒重的影响因品种和籽粒着生位置而异; 外源喷施ABA使籽粒粒重增加, 明显提高下部二次枝梗和同枝梗上迟开花籽粒粒重。因此, 增加籽粒活跃灌浆期ABA含量可以提高蔗糖转化为淀粉的生化效率, 促进弱势粒充实。

关键词：脱落酸; 籽粒灌浆; 粒位; 水稻

收稿：2013-04-25   修定：2013-07-15

资助：国家自然科学基金项目(30400276和31171490)、江苏省自然科学基金(BK2011269)和江苏省“333高层次人才培养工程”项目。

Difference of Abscisic Acid Content in Grains at Different Spikelet Positions of Rice and Its Relationship with Grain Filling

DONG Ming-Hui^1,2,*, GU Jun-Rong¹, CHEN Pei-Feng¹, LIU Teng-Fei¹, ZHAO Bu-Hong³

¹Suzhou Academy of Agriculture Sciences, Suzhou, Jiangsu 215155, China; ²Fostering Base for the National Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Yangzhou University, Yangzhou, Jiangsu 225009, China; ³Lixiahe Region Ag-ricultural Research Institute of Jiangsu, Yangzhou, Jiangsu 225007, China

Corresponding author: DONG Ming-Hui; E-mail: mhdong@yzu.edu.cn; Tel: 0512-65382356

Abstract:

To investigate the changes of abscisic acid (ABA) content in grains at different spikelet positions of rice and explore their relations with grain-filling rates, two super rice genotypes, ‘Yangliangyou 6’ (indica rice) and ‘Wuyunjin 24’ (japonica rice) were field-grown. The changes of ABA content in each group of spikelets at middle part on a panicle during grain filling were determined. Meanwhile, to test and verify the hypothesis that ABA is involved in mediating the postanthesis development of the different categories of spikelets, low concentration (75.7 μmol·L^-1) of ABA was sprayed on the two genotypes at early grain-filling stage. The results showed that earlier-flowered spikelets exerted dominance over later-flowered ones in grain-filling rate and grain weight. There was no difference between the two genotypes. Later-flowered spikelets contained higher concentration of soluble sugars than the earlier-flowered ones at early grain-filling stage, indicating that carbohydrate supply may not be a limiting factor to the development of inferior spikelets. Similar to grain-filling rate, earlier-flowered spikelets contained a higher ABA content than later-flowered ones. The grain-filling rate was significantly and positively correlated with ABA content. Application of low concentration of ABA at early grain-filling stage significantly increased grain weight of those later-flowered grains on the proximal secondary branch and the same branch. The results indicate that low ABA content in inferior spikelets results in their poor grain filling, and a higher ABA content in rice spikelets is required to maintain a faster grain-filling rate. Above all, the results suggest that the promotion of ABA content in grains at earlier grain-filling stage could enhance the transformation efficiency of sucrose to starch, and eventually accelerate grain filling.

Key words: abscisic acid; grain filling; spikelet position; Oryza sativa