• ISSN 1008-505X
  • CN 11-3996/S

氮磷钾配施缓解花期高温胁迫对玉米产量形成的影响

Mitigation effects of NPK fertilization on maize yield formation under high-temperature stress during flowering stage

    摘要
  • 摘要:
    目的 探究氮磷钾配施对花期高温胁迫下玉米产量形成的影响，为缓解玉米高温热害提供养分管理措施。
    方法 以耐高温品种MY73和高温敏感型品种先玉335(XY335)为试验材料进行盆栽试验。设置氮(N)、氮磷(NP)、氮钾(NK)、氮磷钾(NPK)及氮磷钾均不施(CK) 5个处理，于玉米抽雄期开始高温胁迫(日均40.7℃)和常温(日均29.5℃)处理，持续8天。在高温处理结束前一天测定叶片光合特性，成熟期测定植株生物量、果穗结实、产量及籽粒品质等指标。
    结果 (1)高温处理下品种MY73和XY335的产量较常温分别显著下降了36.2%～46.8%和39.9%～58.8%。高温下，两品种产量在N、NP、NK、NPK处理下均依次递增，与CK相比，MY73的增幅分别为18.1%、34.5%、42.5%、54.8%，XY335分别为14.2%、34.4%、87.4%、102.5%，耐高温品种MY73和高温敏感型品种XY335产量在NK和NPK处理间均差异不显著。(2)各施肥处理下两品种穗长、穗粗、穗粒数和百粒重受高温影响均降低，MY73分别下降10.5%～18.6%、4.8%～10.2%、13.7%～25.8%和17.0%～19.3%，XY335下降14.2%～28.7%、14.1%～21.0%、33.0%～45.4%和14.0%～20.5%；高温和常温下两品种穗部性状均以NPK处理最优，NK处理品种MY73的穗长、穗粗、穗粒数和百粒重与NPK差异不显著，而XY335的穗长和穗粒数显著低于NPK处理。(3)高温处理下，各施肥处理MY73和XY335的净光合速率(Pn) 分别较常温下降了24.3%～32.0%和23.3%～41.8%；高温条件下，两个品种在N、NP、NK、NPK处理的Pn均呈递增趋势，与CK相比，N、NP、NK、NPK处理MY73和XY335的Pn分别提高了4.7%、16.6%、20.0%、31.3%和20.3%、34.9%、37.9%、46.2%，均以NPK处理的效果最优。(4)温度和肥料分别对籽粒粗脂肪和粗蛋白影响显著，而品种因素主要影响赖氨酸和粗淀粉含量，常温和高温下MY73的粗淀粉含量在各施肥处理下均高于XY335。
    结论 抽雄后高温胁迫显著降低玉米的穗长、穗粗、穗粒数和百粒重，导致产量下降，且热敏感型品种XY335降幅大于耐热型品种MY73。高温条件下，施用NPK、NK、NP、N肥可不同程度地提升叶片净光合速率、气孔导度和胞间二氧化碳浓度，改善穗部性状，提高产量，进而缓解高温对两品种产量的抑制效果，提高玉米品种的综合耐热系数。缓解效果尤以NPK配施最为显著。

     

    Abstract:
    Objective The effects of different nitrogen, phosphorus and potassium fertilizer combinations on maize yield formation were studied under high-temperature stress during flowering stage, aiming to provide a nutrient management strategy for alleviating heat damage in maize.
    Methods A pot experiment was conducted using a heat-tolerant cultivar MY73 and a heat-sensitive cultivar Xianyu 335 (XY335). Five fertilization treatments were applied: nitrogen alone (N), nitrogen-phosphorus (NP), nitrogen-potassium (NK), nitrogen-phosphorus-potassium (NPK), and no fertilizer control (CK). High temperature stress (mean 40.7℃) and normal temperature (mean 29.5℃) treatment were imposed at the tasseling stage for 8 days. Leaf photosynthetic characteristics were measured one day before the end of high-temperature treatment. At maturing stage, plant biomass, ear traits, grain yield and quality were determined.
    Results (1) Under high-temperature, the grain yield of both MY73 and XY335 significantly decreased by 36.2%−46.8% and 39.9%−58.8%, respectively, compared with normal temperature. Under high temperature, the yield of both cultivars increased progressively in the order of N, NP, NK, and NPK. Compared with CK, yields of MY73 increased by 18.1%, 34.5%, 42.5%, 54.8%, yields of XY335 increased by 14.2%, 34.4%, 87.4%, 102.5%, respectively, under high temperature. For both the heat-tolerant cultivar MY73 and the heat-sensitive cultivar XY335, there was no significant yield difference between NK and NPK treatment under high-temperature. (2) Under high temperature, the ear length, ear diameter, kernel number per ear, and 100-grain weight of both maize cultivars decreased across fertilizer treatments, with MY73 decreased by 10.5%−18.6%, 4.8%−10.2%, 13.7%−25.8%, and 17.0%−19.3%, respectively, XY335 decreased by 14.2%−28.7%, 14.1%−21.0%, 33.0%−45.4%, and 14.0%−20.5%, respectively. NPK treatment resulted the highest values for all the ear traits. It was found that there was no significant difference in ear traits between NK and NPK treatment for MY73, whereas the ear length and kernel number per ear of XY335 in NK were significantly lower than in NPK treatment. (3) High temperature reduced the net photosynthetic rate (Pn) of MY73 and XY335 by 24.3%−32.0% and 23.3%−41.8%, respectively. Under high temperature, the Pn of both cultivars increased progressively with treatments from N to NPK; compared with CK, the Pn of MY73 increased by 4.7%, 16.6%, 20.0%, 31.3%, respectively, and the Pn of XY335 increased by 20.3%, 34.9%, 37.9%, 46.2%, respectively, with the NPK treatment consistently performed the best. (4) Temperature and fertilizer had significant effects on crude fat and crude protein in grains, respectively, while the cultivar factor primarily influenced lysine and crude starch content. The crude starch content of MY73 was higher than that of XY335 in all fertilization treatments under both temperature conditions.
    Conclusion High-temperature during tasseling stage reduced ear length, ear diameter, kernel number per ear, and 100-grain weight, leading to yield loss, with greater reduction in the heat-sensitive cultivar XY335 than in the heat-tolerant cultivar MY73. Under high temperature stress, fertilization stimulated the net photosynthetic rate, enhanced ear traits, and ultimately grain yield, thereby alleviating heat-induced yield suppression. NPK combined application showed the most significant mitigation effect and improved the comprehensive heat-tolerance coefficient of both cultivars.

     

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