长期不同施肥处理对高粱花后叶片衰老、抗氧化酶活性及产量的影响

Impacts of long-term fertilization on post-anthesis leaf senescence,antioxidant enzyme activities and yield in sorghum

高粱花后叶片缓慢衰老及持绿能提高高粱应对干旱等逆境胁迫能力,也与籽粒产量密切相关;在育种上已将叶片抗早衰性作为育种的优异性状以提高谷物产量及稳定性,栽培措施(包括施肥)也能够提高高粱花后叶片的抗早衰能力。为探明长期不同施肥处理对高粱花后叶片抗早衰性和叶片功能的影响,2020和2021年在大田条件下研究了长期单施氮磷钾化学肥料(NPK)、化学肥料结合有机肥(NPKM)、化学肥料结合有机肥和秸秆还田(NPKMS)、有机肥和秸秆还田(MS)和不施肥(CK)各处理对高粱花后叶面积变化、叶片SPAD值、单位叶面积氮累积量(SLN)、叶片抗氧化酶活性及籽粒产量等影响。结果表明,施肥提高了高粱花后持绿叶面积、SPAD值和SLN值;与NPK比较,NPKM、NPKMS和MS能够有效控制持绿叶面积的衰减,提高上中下3个部位叶片的SPAD值和SLN值,其中MS与NPK处理氮投入相当。施肥也提高了不同部位叶片的SOD、POD和CAT抗氧化酶活性,降低了MDA的含量;与NPK比较,NPKM、NPKMS和MS显著提高了SOD、POD和CAT抗氧化酶活性和降低了MDA的含量。与CK和NPK比较,NPKM、NPKMS和MS显著提高了单穗粒数而提高了高粱籽粒产量。为此,长期施用有机肥结合秸秆还田即能代替化肥,又能防止高粱叶片早衰提高高粱产量。

Post-anthesis delayed leaf senescence and stay-green leaf phenotype are typically associated with the increasing yield,which offers the potential to increase crop resilience to drought stress.Retarded leaf senescence is beneficial to maintain cereal yield adaptability and stability.Many different management approaches,including fertilization,can modulate leaf senescence as well.The impacts of different long-term fertilization treatments on sorghum post-anthesis leaf senescence,antioxidant enzyme activities,and the yield were explored in 2020 and 2021 in this study.There were five treatments,which included chemical fertilizers of NPK(NPK),NPK plus manure(NPKM),NPK plus manure and straw returning(NPKMS),manure plus straw returning(MS),and fertilizer withdrawn(CK).Fertilizer application enhanced green leaf area per plant,SPAD reading and specific leaf nitrogen(SLN)compared with the control.Compared with NPK,the treatments of NPKM,NPKMS along with MS delayed post-anthesis attenuation of leaf area per plant and enhanced the values of SPAD and SLN in spite of the similar N application for NPK and MS.The treatments of NPK,NPKM,NPKMS,and MS increased antioxidant activities of SOD,POD,and CAT conjugate with a decreasing MDA content compared with the control.Among those,higher antioxidant enzymes activities and lower MDA content were induced by NPKM,NPKMS,and MS than NPK.In conclusion,NPKM,NPKMS,and MS promoted sorghum grain yield due to the increased grain number per panicle.Therefore,long-term application of manure combined with straw returning can not only replace chemical fertilizer but also delay leaf senescence,which leading to high grain yield in sorghum.