Grain filling is the final growth stage in cereals when fertilized ovaries develop into caryopses.The degree and rate of grain filling in rice spikelets differ largely with grain positions on a panicle and photosynthate accumulated in the stem sheath before and after flowering.A rice panicle is usually divided into inferior spikelets and superior spikelets,the poor grain-filling of inferior spikelets is more aggravated in the new bred "super" rice cultivars that have numerous spikelets on a panicle.In order to further investigate the mechanism,and the cultivation measures to improve the yield potential of "super" rice cultivars,two "super" hybrid indica rice cultivars,Yangliangyou 6 and Ⅱ you 084,were field-grown with treatments of two applications of wheat straw (all wheat straw residue applied to field,SRF; no wheat straw residue applied to field,NSRF) and two applications of nitrogen (the basic and tiller fertilizer to the panicle fertilizer=5:5,N1; and 7:3,N2).The accumulations of dry matter and NSC (non-structural carbohydrates) in stem and sheath,transportation percentage,and grain-filling characteristic in superior and inferior spikelets under nitrogen application amount of 225 kg ha-1 were measured.The results showed that the SPAD values of leaves and dry matter accumulation of stem and sheath in treatment of NSRF were higher than those in SRF before heading,which was on the contrary after heading.The SPAD values of the N2 were higher than those of the N1 before heading,but the dry matter accumulation of stem and sheath and its transportation percentage of the N2 were higher than those of the N1 at each growth stage,there was no significant difference before heading,while significant diffrence at heading and ripening periods.The interactions of the SFR and the N2 significantly enhanced dry matter accumulation in stem and sheath,output from stem and sheath,transportation percentage and NSC transportation percentage at mid and late grain-filling stages.Grain weight of the superior or inferior spikelets was positively and significantly or very significantly correlated with dry matter accumulation from heading to ripening,NSC accumulation in stem and sheath at heading,and dry matter weight in stem and sheath at ripening,while negatively and significantly correlated with NSC accumulation at ripening.The positive corrections between the initial growth power of the superior or inferior grains and the NSC accumulation of stems and sheath at heading,between the mean grain-filling rate and the NSC accumulation of stems and NSC transportation percentage at heading stage,between the maximum grain-filling rate of the superior grains and NSC accumulation and NSC translocation efficiency at heading,and between the maximum grain-filling rate of the inferior grains and the NSC transportation percentage were significant or very significant.%为探究不同栽培条件和耕作方式对大穗型超级稻籽粒灌浆结实的影响及不同粒位籽粒间差异,寻求超级稻高产优质栽培调控途径.以超级杂交籼稻扬两优6号和Ⅱ优084为材料,设置麦秸还田和氮肥运筹两因素试验,研究其对茎鞘光合同化物生产、运转及强、弱势粒灌浆特性影响.结果表明,抽穗前麦秸不还田处理(A1)的叶片SPAD值和茎鞘干物质积累量大于麦秸还田处理(A2),抽穗期以后则相反；抽穗前,基蘖肥∶穗肥=7∶3(B2)的处理叶片SPAD值高于基蘖肥∶穗肥=5∶5(B1)处理,生育各期茎鞘物质积累量与运转率均为B2大于B1,但干物质积累量抽穗期前差异不大,抽穗与成熟期呈显著与极显著差异；A2与B2互作显著提高生育中后期茎鞘干物质积累量、茎鞘物质输出率与运转率及非结构性碳水化合物(NSC)运转率；强、弱势粒粒重与抽穗至成熟期干物质积累量、抽穗期茎鞘NSC积累量、成熟期干物质量均呈显著正相关,与成熟期NSC积累量呈显著负相关；强、弱势粒的起始灌浆势与抽穗期NSC含量均呈极显著正相关,平均灌浆速率与抽穗期NSC含量及运转率呈显著正相关,强势粒的最大灌浆速率与抽穗期NSC含量及NSC运转率呈显著正相关,弱势粒的最大灌浆速率与NSC运转率呈显著正相关.
展开▼
