Abstract: The grain filling characteristics of six rice varieties (combinations) and the relationships between their relative biochemical composition during phytate formation and grain plumpness were studied. For rice varieties (combinations) ISHR1, ISHR2, R198 and JW21 with good grain plumpness, the two step filling in superior grains and inferior grains would not be clear. While for rice varieties (combinations) ISHR3 and 559 with poor grain plumpness, the two step filling in superior grains and inferior grains expressed very clearly. From booting stage to flowering stage, the contents of phytate and inositol in the varieties with good grain plumpness were obviously higher than those in the varieties with poor grain plumpness. While at grain filling stage, inorganic phosphorus content was obviously higher than that in the varieties with good grain plumpness. The contents of phytate and inositol from booting stage to flowering stage were very significantly correlated with the initial filling power (P₀), average grain filling rate (R_A) and inorganic grain filling percentage(GFP), and inorganic phosphorus content at grain-filling stage was significantly and negatively correlated with P₀, R_A and GFP. Furthermore, effective approaches to improve grain filling were put forward.

Key words: grain filling, phytate, inositol, inorganic phosphorus, rice

摘要： 研究了6个水稻品种（组合）的籽粒灌浆特征及植酸合成过程中相关生化成分变化与籽粒充实的关系。籽粒充实度好的亚杂1号(ISHR1)、亚杂2号（ISHR2）、R198和JW21，强、弱势粒灌浆不表现两段灌浆现象，而籽粒充实度差的亚杂3号（ISHR3）和559两段灌浆现象则十分明显。孕穗期至开花期，籽粒充实度好的品种其植酸、肌醇含量显著高于籽粒充实度差的品种；灌浆期，籽粒充实度差的品种无机磷含量明显高于籽粒充实度好的品种。相关分析表明，在孕穗期至开花期籽粒中植酸、肌醇含量与起始灌浆势（P0）、平均灌浆速率（RA）和籽粒充实率（GFP）均呈极显著正相关；灌浆期，无机磷含量与P0、RA和GFP呈极显著负相关，肌醇含量与P0、RA和GFP无明显相关性。提出了提高水稻籽粒充实度的有效途径。

关键词: 灌浆, 植酸, 肌醇, 无机磷