不同耐低氮性玉米品种的花后碳氮积累与转运特征

为了探明不同耐低氮性玉米品种生育后期碳、氮物质积累与转运特性及其对氮肥响应的差异,以期为品种高效施氮技术的制定提供理论依据。以耐低氮品种‘正红311’(Zhenghong311,ZH311)和低氮敏感品种‘先玉508’(Xianyu 508, XY508)为材料,设置4个氮肥用量(0、150、300和450 kg hm–2),于2017—2019年研究氮肥水平对不同耐低氮性玉米品种生育后期物质,包括干物质、全氮和非结构性碳水化合物(non-structural carbohydrate, NSC)积累和转运的影响。结果表明,供氮不足时,玉米通过增加花前贮存碳、氮物质对籽粒的转运以保证产量。增施氮肥能够提高玉米花后干物质和碳水化合物生产及其对籽粒质量的贡献率。与低氮敏感品种先玉508相比,在低氮条件下,耐低氮品种正红311在花前、花后均保持较高的植株干物质、NSC和氮素量,花后物质积累量及其对籽粒质量的贡献率更高,从而拥有更高的籽粒产量;品种间花前物质转运率及其对籽粒质量的贡献率差异不大。面对低氮胁迫,正红311既保证了花前贮存物质充分向籽粒运输,同时维持着较高的同化物积累能力来影响其产量形成。

Characteristics of post-anthesis carbon and nitrogen accumulation and translocation in maize cultivars with different low nitrogen tolerance

To understand the suitable amount of nitrogen(N)application and the potential of increasing yield and improve efficiency for the maize cultivars with different low N tolerance.The experiment was setting from 2017 to 2019,the low-N tolerant cultivar‘Zhenghong 311(ZH311)’and the low-N sensitive cultivar‘Xianyu 508(XY508)’were selected and four N application rates(0 kg hm-2,150 kg hm-2,300 kg hm-2,and 450 kg hm-2)were set to investigate the effects of N level on carbon(C)and N accumulation and translocation in the later growth stage of different maize cultivars.The results showed that in low N environment,maize increased the C and N translocations of pre-silking to the grain to ensure the yield.Increasing the N fertilizer applications could improve the contribution rates of dry matter and carbohydrate to grain yield.Compared with XY508,ZH311 had higher accumulations of plant dry matter,N and non-structural carbohydrate(NSC)of pre-and post-silking,and higher contribution rates of dry matter,N and accumulations to grain yield of post-silking,so it had higher grain yield.There was no significant difference between cultivars in the rate of dry matter,N and NSC translocation of pre-silking.In the face of low N stress,ZH 311 not only ensured the sufficient C and N translocations of pre-silking to the grain,but also maintained a higher capacity of assimilate accumulation to affect the yield formation.