PAC对谷子花后土壤氮素供应和叶片抗氧化特性的影响

全基施肥方式会造成作物全生育期内营养供应失衡,导致生育后期缺氮早衰。为探究聚天门冬氨酸和壳聚糖复配剂(PAC)保障谷子(Setariaitalica)花后氮素供应和调控叶片抗氧化特性的机制,建立全基施肥背景下东北春谷防衰增产的生产技术,于2020–2021年在中国农业科学院作物科学研究所公主岭试验站开展大田试验,以谷子品种张杂谷13号和华优谷9号为材料,设置常规氮素(CN)和PAC配合氮素(PN) 6个氮素水平(0、75、112.5、150、225和337.5 kg·hm^–2)播种前进行全基施肥处理。结果表明,与常规氮肥处理相比,相同施氮量下,PAC处理后,两品种谷子花期和灌浆中期0–20cm和20–40 cm土层土壤硝态氮和铵态氮含量升高,花后叶面积显著增大,叶面积降幅减小;花后0–40天旗叶超氧化物歧化酶、过氧化物酶及过氧化氢酶活性升高,丙二醛含量降低。因此, PAC有效保障了谷子生育中、后期土壤氮素的供应,提高了叶片抗氧化能力,延缓了叶片衰老进程,进而提高产量。2020年和2021年Z13的增产幅度分别为11.24%–21.55%和8.65%–14.22%,...

Effects of PAC on Soil Nitrogen Supply and Leaf Antioxidant Properties in Foxtail Millet at Anthesis Stage

The way of one-time basic fertilizer application causes imbalance of nutrients supplies in the whole growth period of crops, which results in the deficiency of nutrients and premature senility in the late growth period. In order to investigate the mechanism of polyaspartic acid-chitosan (PAC) in soil nitrogen supply and regulation of antioxidant properties in foxtail millet leaf after flowering in the northeast China and establish an anti-aging and high-yielding technology under the background of one-time basic fertilizer application, a field experiment was conducted using foxtail millet (Setaria italica) varieties of Zhangzagu 13 and Huayougu 9 in Gongzhuling Experimental Station of Institute of Crop Sciences (Chinese Academy of Agricultural Sciences) from 2020 to 2021. Conventional fertilization (CN) and PAC with fertilization (PN) treatments were set under six nitrogen levels of 0, 75, 112.5, 150, 225, and 337.5 kg·hm^-2 with all fertilizer applicated before sowing. Our results showed that, compared with CN under the same nitrogen application level, PAC increased NO₃^--N and NH₄⁺-N content in the 0-20 cm and 20-40 cm soil layers of two foxtail millet varieties at anthesis and mid-filling stage. Meanwhile, PAC increased leaf area and decreased leaf area reduction per plant significantly. The activities of superoxide dismutase, peroxidase and catalase of the flag leaf increased but the content of malondialdehyde reduced in 0-40 days after flowering. Thus, PAC ensures the supply of nitrogen in soil during the middle-late growth period, increases the antioxidant properties of leaf to delay the progress of leaf senescence and increase yield of foxtail millet effectively. In 2020 and 2021, the yield of Zhangzagu 13 increased by 11.24%-21.55% and 8.65%-14.22%, respectively, and the yield of Huayougu 9 increased by 5.53%-15.75% and 10.43%-16.17%, respectively, compared with CN under the same nitrogen application level. The effect of the items above was more significant at low-middle nitrogen application levels of 75, 112.5 and 150 kg·hm^-2. Therefore, PAC combined with nitrogen fertilizer could be an anti-aging and high-yielding cultivation technique in foxtail millet production in the northeast China spring-sowing region.