中文摘要：

【目的】研究小麦强、弱势籽粒淀粉积累与库容量、库活性间的关系及不同穗型间的差异。【方法】以密穗型小麦品种鲁麦21、济麦20和疏穗型小麦品种山农1391、山农12为材料，对籽粒发育过程中强、弱势粒淀粉积累、胚乳细胞数目及相关酶活性变化进行比较。【结果】两种类型小麦强势粒直、支链淀粉积累量均高于弱势粒，密穗型小麦籽粒直、支链淀粉积累量在强、弱势粒间的差异幅度高于疏穗型小麦。Logistic方程拟合籽粒淀粉积累进程表明，强势粒淀粉积累量较弱势粒高的原因是其积累启动时间较早和淀粉积累速率较高；密穗型小麦强、弱势粒淀粉积累速率的差异幅度较大，是造成其籽粒最终淀粉积累量在强、弱势粒间的差异幅度大于疏穗型的原因之一。小麦强势粒胚乳细胞数目显著高于弱势粒，与疏穗型小麦相比，密穗型小麦强、弱势粒胚乳细胞数目的差异幅度较大。4个小麦品种弱势粒蔗糖含量在灌浆期均高于强势粒，说明籽粒蔗糖含量即淀粉合成底物的供给并不是造成强、弱势粒淀粉积累存在差异的限制因子。小麦强势粒蔗糖合酶（SS）、腺苷二磷酸葡萄糖焦磷酸化酶（AGPP）、可溶性淀粉合酶（SSS）和颗粒结合态淀粉合酶（GBSS）活性均高于弱势粒，密穗型小麦强、弱势粒上述酶活性差异幅度均较疏穗型大。【结论】小麦库容量（胚乳细胞数目）和库活性（淀粉合成相关酶活性）是制约强、弱势粒淀粉积累的主要因素。密穗型小麦强、弱势粒间的胚乳细胞数目和淀粉合成相关酶活性差异较大，这可能是造成密穗型小麦籽粒淀粉积累量在强、弱势粒间的差异幅度大于疏穗型的原因。

英文摘要：

[ Objective] The objectives of this study were to elucidate the relationship between starch accumulation and grain sink strength in superior and inferior grains of wheat, and to characterize the variance between the compact and loose spike cultivars in the starch accumulation and grain sink strength in superior and inferior grains. [Method] The field experiments were carried out at Tai＇an Experimental Station of Shandong Agricultural University in two growing seasons from October 2005 to June 2006 and from October 2006 to June 2007. Two loose spike wheat cultivars, SN1391 and SN12, and two compact spike wheat cultivars, LM21and JM20, were chosen in this study. Heads flowering on the same date were labeled with red thread after full heading. Spikes were sampled at 5-day intervals after anthesis till maturity, and partitioned into two groups, superior grains （the 1^st and 2^nd grains from the basal part of middle spikelets） and inferior grains （the 3^st and 4^nd grains from the basal part of middle spikelets）. The starch composition accumulation, endosperm cell numbers and activities of enzymes involved in starch synthesis were examined during grain development of winter wheat. [ Result ] The results showed that the accumulation of amylose and amylopectin in superior grains were significantly higher than those in inferior grains in both spike type cultivars. But the magnitude of difference in amylose and amylopectin accumulation between superior and inferior grains in compact spike wheat cultivars was large as compared with that in loose spike wheat cultivars. The accumulation courses of starch were well fitted to the logistic equation by relating starch contents against days after anthesis. Logistic simulation revealed that the higher starch accumulation in superior grains resulted from earlier initiating accumulation time and greater accumulation rate. There was a larger difference in starch accumulation rates between superior and inferior grains in compact spike wheat cultivars as compared with that in