Variations in Carbohydrate and Protein Accumulation among Spikelets at Different Positions Within a Panicle During Rice Grain Filling

• Published in: Rice science Vol. 19; no. 3; pp. 223 - 232
• Main Authors: DONG, Ming-hui, CHEN, Pei-feng, XIE, Yu-lin, QIAO, Zhong-ying, YANG, Jian-chang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2012; Suzhou City Academic of Agriculture sciences, Suzhou 215155, China%Suzhou City Academic of Agriculture sciences, Suzhou 215155, China%Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Yangzhou University, Yangzhou 225009, China; Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Yangzhou University, Yangzhou 225009, China
• Subjects: accumulation dynamic; amylose; bioactive properties; crude protein; cultivars; filling period; flowering; grain filling; grain quality; inflorescences; protein; rice; seeds; spikelet position; starch; sugar content; sugars; variation; water content; whole grain foods; 位置; 可溶性糖含量; 小穗; 水稻籽粒; 直链淀粉含量; 碳水化合物; 籽粒灌浆过程; 蛋白质积累; spikelet position; protein; accumulation dynamic; starch; rice; variation; grain filling
• ISSN: 1672-6308; 1876-4762
• DOI: 10.1016/S1672-6308(12)60044-4

The accumulation dynamics of kernel components for spikelets at different positions within a rice panicle were investigated during grain filling to understand the physiological reasons for the variation of grain quality. Two rice cultivars, Yangdao 6 (indica) and Yangjing 9538 (japonica), were field-grown, and the grain filling characters and contents of starch, soluble sugar, and protein of the spikelets at different positions were studied. There were significant differences in matter accumulation among spikelets at different positions during grain filling. The early-flowering spikelets presented dominance over the late-flowering spikelets in initial time and initial rate of accumulation. At the initial and mid filling stages, the contents and the rates of starch and amylose accumulation in spikelets decreased with the flowering sequence, but soluble sugar content (SSC) exhibited the opposite trend. The difference in SSC among the spikelets of Yangjing 9538 was greater than that of Yangdao 6, but amylose content in mature spikelets showed no obvious relationship to their flowering sequence. The crude protein content (CPC) of early-flowering spikelets decreased more rapidly than that of late-flowering ones at the initial filling stage, and CPC in the spikelets on the secondary branch was higher than that on the primary branch, but CPC in early-flowering ones was lower than that in late-flowering across the whole grain filling period. Grain water content (GWC) of early-flowering spikelets decreased more rapidly than that of late-flowering spikelets on the same branch at the initial and mid filling stages, especially for the top grain on each primary branch. The results suggested that poor grain filling of late-flowering spikelets may be attributed to their low biological activity rather than carbohydrate supply limitation.