【摘要】 [目的]研究通过调整小麦种植密度构建高光能利用效率群体,促进群体氮素积累、分配和转运的效果和机理,为充分利用光能提高小麦产量提供理论依据。[方法]试验于2018—2019年在安徽省濉溪县和蒙城县进行,以分蘖能力强(安1302)和弱(皖垦麦0622)的品种为材料,设置180×10~4株/hm~2 (D1)、240×10~4株/hm~2(D2)、300×10~4株/hm~2(D3)、360×10~4株/hm~2 (D4)4个种植密度,调查了群体籽粒产量、光合有效辐射截获率和截获量、光合有效辐射转化率,以此为基础,将小麦群体分为光效率高、中、低3个类型,比较了不同光效率类型群体的叶面积指数、花前氮素积累和转运量、花后(乳熟期)氮素积累量。[结果]品种、密度及其互作效应显著影响小麦群体的光能利用率和籽粒产量。高光效型群体的光能利用率和籽粒产量分别达1.4%和9.7 t/hm~2,分别比中、低效型群体提高5%、14%和1%、5%。不同群体间开花期、乳熟期光合有效辐射截获率、开花期至乳熟期光合有效辐射截获量差异不显著,高光效型群体开花期至乳熟期光合有效辐射转化率高于中、低效型群体,达2.34 g/MJ。高光效型群体开花期、乳熟期叶面积指数及开花期茎秆叶鞘、叶片、单位叶面积氮素积累量均不同程度高于其他类型群体,分别达7.24、4.53及63.9 kg/hm~2、79.5 kg/hm~2和143.78μg/cm~2。此外,高光效型群体中群体和单茎花前氮素转运量分别为129 kg/hm~2和15 mg,均显著高于中、低效型群体,主要为茎秆+叶鞘和叶片氮素转运量较高,各营养器官间氮素转运率差异不显著,且高光效型群体成熟期个体营养器官仍保持较高的氮素积累量。[结论]高光效型群体开花期茎秆+叶鞘、叶片以及单位叶面积氮素积累量高,提高了开花期的叶面积指数,有利于光能的吸收和利用。虽然高光效型群体茎秆+叶鞘和叶片中的氮素转运量较高,其花后营养器官的氮素积累量依然较高,有助于维持花后较大叶面积指数,有效提升花后光合有效辐射转化率,获得更高的小麦籽粒产量。更多还原

【Abstract】 [Objectives] We constructed different types of radiation use efficient populations through the plant densities of wheat,and compared their N accumulation and transport characteristics before anthesis and the N accumulation after anthesis,to provide a theoretical base for improving wheat yield through efficient radiation use efficiency(RUE).[Methods] Field trials were conducted in Suixi and Mengcheng counties of Anhui Province in 2018-2019,the cultivar "An 1302" with strong tillering ability and "Wankenmai 0622" with weak tillering ability were employed as the test materials.Four plant densities:180×10~4 plants/hm~2(D1),240×10~4 plants/hm~2(D2),300×10~4 plants/hm~2(D3),and 360×10~4 plants/hm~2(D4) were set up for the investigation of yield,and the interception rate,amount,and photosynthetic conversion efficiency of active radiation at milk-ripening stage.According to these data,the wheat population was divided into high,moderate and low radiation use efficient types,denoted as H-,M-,and L-RUE,respectively.The N accumulation and translocation during anthesis stage,and the N accumulation and leaf area index at milk-ripening stage were compared among the three population types.[Results] Cultivar,density and their interaction significantly affected the RUE and grain yield.The RUE and grain yield of H-RUE population were 1.4% and 9.7 t/hm~2,which were higher than those of M-and L-RUE by5% and 14%,1% and 5%,respectively.The interception rate at anthesis and milk-ripe stages,and the interception amount of available radiation from anthesis to milk-ripe stages were not significantly different among the three population types,but the photosynthetic conversion efficiency of H-RUE was 2.34 g/MJ,which was higher than that of M-and L-RUE population.The H-RUE population had a higher leaf area index at anthesis(7.24) and milkripe stages(4.53),and higher N accumulation in stem & leaf sheath(63.9 kg/hm~2),leaves(79.5 kg/hm~2),and per unit leaf area(143.78 μg/cm~2) at anthesis,compared to the other population types.In addition,H-RUE population and the individual stem had similar translocation rate of N at pre-anthesis stage with the M-and L-RUE populations and the individual stems,but had significantly higher N translocation amount due to their higher N accumulation amount.The leaf area index of H-RUE population was significantly higher than the M-and L-RUE populations at anthesis and milk-ripening stage as well.[Conclusions] The wheat population with high radiation use efficiency could accumulate more N in stems & leaf sheaths,and leaves,and has higher N accumulation amount per unit leaf area before anthesis stage,in spite of higher translocation amount of N,the N accumulation in the vegetative organs is higher than those in the moderate and low radiation use efficiency populations,so the population maintains high leaf area index at anthesis and milk-ripening stage,which is inductive to the radiation conversion and the formation of yield.更多还原