新老玉米品种花粒期干物质及氮素积累转运机制的差异分析

Difference Analysis of Dry Matter and Nitrogen Accumulation and Translocation Mechanism of New and Old Maize Varieties Flowering to Maturity Stage

为明确新老玉米品种各器官干物质及氮素积累和分配的差异,以我国20世纪70年代主推杂交品种中单2号和21世纪前10年的主推杂交品种先玉335和郑单958为材料,设置追氮100,200 kg/hm^2以及密度5.25万,7.50万,10.50万株/hm^2等处理,以阐明其氮素营养策略和调整机制差异。结果表明,玉米新品种花前干物质较老品种高0.43 t/hm^2,且新品种吐丝期茎秆生物量与叶片生物量的比值为2.53,比老品种显著低11.7%;新品种吐丝期茎秆氮积累量与叶片氮积累量的比值为0.76,较老品种显著低15.8%,新品种叶片氮素运移对籽粒氮积累的贡献较老品种平均高出4.3%;2年间新品种平均6.21%的花前叶片干物质和24.7%的花前茎秆干物质在整个花后籽粒灌浆期阶段外运,老品种平均为12.7%,29.1%。在各种栽培条件下,玉米叶片转运氮素占吐丝期叶片氮积累量的比例始终保持在63%左右,而茎秆为60%左右。新品种花前干物质和氮素积累策略是更加侧重叶片干物质和氮素积累,老品种则是侧重茎秆,且在灌浆期新品种优先启动茎秆的养分运移,为叶片养分的过早运移提供缓冲,维持灌浆期叶片较高的光合功能,而获得更高产量;在多年来品种更替过程中,新老品种叶片和茎秆的氮素转运极限是相近的,差别在于新品种具有更高效的氮素积累和转运策略,以在不同栽培条件下获得更高的产量。

To search the differences of biomass and nitrogen accumulation and distribution in different organs of new and old hybrids.Field experiment was conducted in which commercial maize hybrids ZD2 at 1970 s and two commercial maize hybrids XY335 and ZD958 at 2000 s,their N fertilization were 100,200 kg/ha,and the plant density were 52 500,75 000,105 000 plants/ha,respectively,to definite the difference of nitrogen nutrition strategy and adjustment mechanism.The results showed that quality of new varieties biomass in pro-silking were higher than old varieties by 0.43 t/ha,the stem/leaf dry matter（2.53） and the stem/leaf nitrogen accumulation at silking（0.76） of new varieties were significant lower than old varieties in silking separately by 11.7% and 15.8%,the leaf removable nitrogen/grain nitrogen at maturity of new varieties was higher than old variaties by 4.3%.In two years,an average of new varieties was 6.21% leaves biomass and 24.7% stem biomass in pro-silking for external transport from R1 to R6,and the average of old varieties was 12.7% leaves dry matter and 29.1% stem biomass.Under different cultivation conditions,the ration of leaf N translation and leaf N accumulation in silking always kept63%,and the stem was 60%.In other words,the biomass and N accumulation strategy in pro-silking of new varieties were more focus on leaves,but the old varieties were more foucs on stem,the new varieties precedent activate stem nutrient transport in post-silking stage,to provide a buffer for leaf nutrient transport prematurely,and ensurethe function of leaves in post-silking stage to obtain higher yield.In the course of variety replacement,the N transport extremity of leaves and stems were similar in new and old varieties,the new varieties had higher N accumulation and translation strategy,to have more higher yield in different cultivation conditions.