知识与财富的链接
为明确种植密度对不同春小麦品种产量形成的影响,以辽春18、辽春43和沈麦155为材料,设置5个种植密度处理,分别为375万、525万、675万、825万和975万株·hm-2（记为D1、D2、D3、D4和D5）,比较分析了不同种植密度对春小麦产量及其构成因素、SPAD值、干物质积累与分配、叶面积指数（LAI）、粒叶比及光合特性的影响。结果表明,种植密度对春小麦产量及其构成因素具有显著调控作用,且品种与密度间存在显著互作效应。随着种植密度增加,3个春小麦品种单位面积有效穗数呈显著增加趋势;而穗粒数和千粒重总体呈下降趋势;产量总体呈先增后降趋势,辽春18和沈麦155均在D4下产量最高,分别为8 206.62和5 057.74 kg·hm-2,辽春43在D2下产量最高,为7 191.61 kg·hm-2;花前干物质转运量、花前干物质转运效率、花前干物质对籽粒产量贡献率、花后干物质积累量、花后干物质对籽粒产量贡献率和旗叶SPAD值总体均呈先升高后降低趋势,且均在D3或D4下达最大;LAI、粒数叶比、粒重叶比、旗叶胞间CO2浓度、净光合速率、气孔导度和蒸腾速率均呈先升高后降低趋势。综合来看,辽春18和沈麦155的适宜种植密度为825万株·hm-2,辽春43的适宜种植密度为525万株·hm-2。
To clarify the effects of planting density on yield formation in different spring wheat cultivars, a field experiment was conducted using three spring wheat cultivars, Liaochun 18, Liaochun 43, and Shenmai 155, under five planting densities of 3.75 million, 5.25 million, 6.75 million, 8.25 million, and 9.75 million plants·hm-2, designated as D1, D2, D3, D4, and D5, respectively. The effects of planting density on grain yield and its components, SPAD value, dry matter accumulation and distribution, leaf area index(LAI), grain to leaf ratio, and photosynthetic characteristics were compared among cultivars. The results showed that planting density significantly affected grain yield and its components, with significant variety and planting density interaction effects. With the increase of planting density, the number of effective spikes per unit area of the three varieties spring wheat showed a significant increasing trend, while the number of grains per spike and 1 000-grain weight generally showed a decreasing trend, and the yield showed an initial increase and then a decrease. The yield of Liaochun 18 and Shenmai 155 reached the highest under the D4 treatment, which were 8 206.62 and 5 057.74 kg·hm-2, respectively, the yield of Liaochun 43 reached the highest under the D2 treatment(7 191.61 kg·hm-2). With the increase of planting density, the dry matter transport before flowering, the dry matter transport efficiency before flowering, the contribution rate of dry matter before flowering to grain yield, the dry matter accumulation after flowering, the contribution rate of dry matter after flowering to grain yield, and the SPAD value of flag leaves all showed a trend of increasing first and then decreasing, and all reached the maximum at D3 or D4 treatments. The LAI, grain number per leaf, grain weight per leaf, intercellular CO2 concentration of flag leaves, net photosynthetic rate, stomatal conductance, and transpiration rate all showed an initial increase and then decrease trend with the increase of planting density. In conclusion, the optimum planting density was 8.25 million plants·hm-2 for Liaochun 18 and Shenmai 155, and 5.25 million plants·hm-2 for Liaochun 43.
