Dense plant cultivation is an efficient approach to improve maize production by maximizing the utilization of energy and nutrients. However, dense plant populations may aggravate the abortion rate of young grains, resulting in fewer kernels per ear. The rate and duration of grain-filling play decisive roles in maize grain yield. Therefore, to increase plant density, enhancing the grain-filling rate, extending the growth period of individual maize plants and regulating crop senescence would be the first priority. In this study, we examined the regulatory effects of GA₄₊₇ under two application methods: shanks and silks were moistened by cotton full with GA₄₊₇ solution at concentrations of 0, 10, 60, and 120 mg L⁻¹. The results showed that GA₄₊₇ improved the grain-filling rate by increasing the content of auxin, gibberellin, zeatin, and abscisic acid in grains compared to control plants. In addition, the auxin, gibberellin, and zeatin contents in the grains were positively and significantly correlated with the maximum grain weight and the maximum and mean grain-filling rates. Moreover, GA₄₊₇ increased the activities of superoxide dismutases, catalases, and peroxidases and reduced the malondialdehyde content in leaves compared with untreated plants. At the concentration of 60 mg L⁻¹, GA₄₊₇ showed the greatest effect on shank and silk applications (Sh-60 and Si-60) followed by 10 mg L⁻¹ (Sh-10) for shank treatment and 120 mg L⁻¹ (Si-120) for silk treatment. Our results suggest that a concentration of 60 mg L⁻¹ GA₄₊₇ for shank and silk application may be efficiently used for changing the level of hormones in grains and antioxidant enzymes in ear leaves, which may be useful for enhancing grain-filling rate and delaying leaf senescence, resulting in an increase in maize grain yield.

中文翻译：

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赤霉素（GA4 + 7）对高密度玉米（Zea mays L.）的籽粒充实，激素行为和抗氧化剂的影响。

密集植物栽培是通过最大限度地利用能量和养分来提高玉米产量的有效途径。但是，密集的植物种群可能会加剧幼粒的流产率，导致每个穗的籽粒更少。籽粒灌浆的速率和持续时间在玉米籽粒产量中起决定性作用。因此，提高植物密度，提高籽粒灌浆率，延长单个玉米植物的生长期和调节作物衰老将是当务之急。在这项研究中，我们研究了GA _{4 + 7}在两种施用方法下的调节作用：小腿和丝被浓度为0、10、60和120 mg L ^-1的GA _{4 + 7}溶液充满棉布润湿。结果表明GA _{4 + 7}与对照植物相比，通过增加谷物中生长素，赤霉素，玉米素和脱落酸的含量，提高了籽粒的灌浆率。此外，谷物中的生长素，赤霉素和玉米素含量与最大谷物重量以及最大和平均籽粒填充率呈正相关且显着相关。而且，与未经处理的植物相比，GA _{4 + 7}增加了叶片中的超氧化物歧化酶，过氧化氢酶和过氧化物酶的活性，并降低了丙二醛含量。在浓度为60 mg L ^-1时，GA _{4 + 7}对小腿和蚕丝的应用（Sh-60和Si-60）显示出最大的作用，其次为10 mg L ^-1（Sh-10）进行小腿处理，然后为120 mg L ^-1（Si-120）用于丝绸处理。我们的结果表明，用于小腿和蚕丝的浓度为60 mg L ^-1 GA _{4 + 7}可以有效地用于改变谷物中激素和耳叶中抗氧化酶的水平，这可能有助于提高谷物的填充率延缓叶片衰老，导致玉米籽粒产量增加。