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为明确不同移栽密度条件下施氮水平对水稻籽粒产量及灌浆特性的影响,设计裂区试验,主处理为氮肥量,副处理为移栽密度,用Richards方程拟合水稻强、弱势粒的灌浆过程,从不同粒位籽粒灌浆特性间的差异认识群体产量构成,以期为进一步提高水稻生产潜力提供理论依据。结果表明:1低密度(15万株/hm~2、21万株/hm~2)条件下,与不施氮处理相比,施氮分别平均增产36.6%、34.6%,且随施氮水平的提高呈增加趋势。高密度条件下(27万株/hm~2、33万株/hm~2),施氮分别平均增产30.8%、18.8%,结实率分别平均降低了2.0%和1.6%,且产量随施氮水平的提高呈先增加后降低趋势。2灌浆特性结果显示,施氮提高了强势粒的最大灌浆速率(GRmax),与不施氮处理(N0)相比平均增加了3.5%,且随施氮水平的提高呈先增加后降低趋势。移栽密度对强势粒平均灌浆速率(GRmean)有明显影响,在低密度(15万株/hm~2、21万株/hm~2)条件下施氮处理强势粒GRmean与不施氮处理相比分别平均降低了2.1%、3.1%,而在高密度(27万株/hm~2、33万株/hm~2)条件下则分别平均增加了1.0%、3.7%;施氮显著提高了弱势粒的GRmax和GRmean,与不施氮处理相比分别平均增加了14.3%、14.4%,且随施氮水平的提高呈先增加后降低趋势。3灌浆阶段性特征显示,灌浆中期强、弱势粒物质积累对籽粒形成的贡献率均最大,分别为58.6%、57.3%。随着施氮水平的提高,中期和后期籽粒的平均灌浆速率(MGR)呈先增加后降低趋势。灌浆持续天数和灌浆贡献率均随着移栽密度的提升而增加。千粒重与弱势粒的GRmax和GRmean呈极显著正相关,与籽粒的起始势(R0)及弱势粒的灌浆活跃期(D)呈显著负相关。结实率与弱势粒GRmean呈显著负相关,与弱势粒的R0呈极显著正相关关系。通过合理密植,同时适当提高施氮水平(27万株/hm~2,165 kg/hm~2),在增加单位面积穗数的同时也提高了水稻个体灌浆速率、增加了有效灌浆持续天数,最终籽粒灌浆充实度好,形成高产。
In order to clarify the effect of nitrogen application rate on grain yield and grain filling characteristics under different transplanting densities, the split zone experiment was designed. The main treatment was nitrogen fertilization and the deputy treatment was transplanting density. Richards equation was used to fit the strong and weak grains of rice Grouting process, from the grain-filling characteristics of different grain-filling differences between groups to understand the composition of production, with a view to further improve the potential of rice production to provide a theoretical basis. The results showed that nitrogen application rate increased by 36.6% and 34.6% on average at low density (150,000 plants / hm ~ 22,100 plants / hm ~ 2) Increase is on the rise. Under high density condition (270,000 plants / hm ~ 23300 plants / hm ~ 2), N application rate increased by 30.8% and 18.8% on average, and seed setting rate decreased by 2.0% and 1.6% on average respectively. The level of increase was increased first and then decreased. 2 Grouting characteristics The results showed that nitrogen application increased the maximum grain filling rate (GRmax) of strong grains, increased by 3.5% on average compared with that of no-nitrogen treatment (N0), and increased firstly and then decreased with the increase of nitrogen application rate. The transplanting density had a significant effect on the average grain filling rate (GRmean) of strong grains. Under the condition of low density (150000 plants / hm ~ 22100 plants / hm ~ 2) Which decreased by 2.1% and 3.1% on average, respectively, but increased 1.0% and 3.7% respectively on average at high density (270,000 plants / hm ~ 23.3 plants / hm ~ 2) Compared with the non-N treatment, GRmax and GRmean of under-treated grains increased by 14.3% and 14.4% on average, respectively, and increased first and then decreased with the increase of N application. 3 The stages of grain filling showed that the contribution of strong and weak grain accumulations in medium grain filling stage was the largest, accounting for 58.6% and 57.3% respectively. With the increase of nitrogen application rate, the average grain filling rate (MGR) increased first and then decreased. The duration of grouting and the contribution of grouting increased with the increase of transplanting density. There was a significant positive correlation between 1000 - grain weight and GRmax and GRmean, but negatively correlated with initial grain potential (R0) and weak grain filling stage (D). Seed setting rate was significantly negatively correlated with the weaker grain GRmean, and significantly negatively correlated with the R0 of the weaker grain. Through the rational close planting and the appropriate increase of nitrogen application rate (270,000 plants / hm ~ 2,165 kg / hm ~ 2), the grain filling rate per unit area was also increased and the effective grain filling duration was increased, while the final grain Filling degree is good, forming a high yield.