Liu Xiaoming, Zhang Liguo, Yu Yang, Qian Chunrong, Li Congfeng, Wei Shi, Li Caifeng, Gu Wanrong
College of Agriculture, Northeast Agricultural University, Harbin, China.
Institute of Maize Research, Heilongjiang Academy of Agricultural Sciences, Harbin, China.
Front Plant Sci. 2022 Jun 23;13:754232. doi: 10.3389/fpls.2022.754232. eCollection 2022.
High-density planting aggravates competition among plants and has a negative impact on plant growth and productivity. Nitrogen application and chemical control can improve plant growth and increase grain yield in high-density planting. Our experiment explored the effects of nitrogen fertilizer and plant growth regulators on maize root-bleeding sap, phosphorus (P) and potassium (K) accumulation and translocation, and grain yield and quality in high-density planting. We established a field study during the 2017 and 2018 growing seasons, with three nitrogen levels of N100 (100 kg ha), N200 (200 kg ha), and N300 (300 kg ha) at high-density planting (90,000 plants ha), and applied Yuhuangjin (a plant growth regulator mixture of 3% DTA-6 and 27% ethephon) at the 7th leaf. Our results showed that N200 application combined with chemical control could regulate amino acid and mineral nutrient concentration delivery rates in root-bleeding sap and improve its sap rate. Also, the treated plant exhibited higher P and K uptake and translocation ability. Furthermore, chemical control and N200 treatment maintained a high level of ribulose-1,5-bisphosphate carboxylase (RuBPCase), phosphoenolpyruvate carboxylase (PEPCase), nitrate reductase (NR), and glutamine synthetase (GS) enzymatic activities in leaves. In addition, plant growth regulator and nitrogen application improved the enzymatic activities of GS, glutamate dehydrogenase (GDH), and glutamic pyruvic transaminase (GPT) and the contents of crude protein, lysine, sucrose, and soluble sugar in grain and ultimately increased maize yield. This study suggests that N200 application in combination with chemical control promotes root vitality and nutrient accumulation and could improve grain yield and quality in high-density planting.
高密度种植加剧了植物间的竞争，对植物生长和生产力产生负面影响。施用氮肥和进行化学调控可改善高密度种植条件下植物的生长并提高谷物产量。我们的试验探究了氮肥和植物生长调节剂对高密度种植玉米伤流液、磷（P）和钾（K）积累与转运以及谷物产量和品质的影响。我们在2017年和2018年生长季开展了田间研究，在高密度种植（90,000株/公顷）条件下设置了三个氮水平，即N100（100千克/公顷）、N200（200千克/公顷）和N300（300千克/公顷），并在第7片叶时施用了玉黄金（一种由3%胺鲜酯和27%乙烯利组成的植物生长调节剂混合物）。我们的结果表明，施用N200并结合化学调控可调节伤流液中氨基酸和矿质养分的浓度输送速率并提高伤流液速率。此外，处理后的植株表现出更高的P和K吸收与转运能力。此外，化学调控和N200处理使叶片中的1,5-二磷酸核酮糖羧化酶（RuBPCase）、磷酸烯醇式丙酮酸羧化酶（PEPCase）、硝酸还原酶（NR）和谷氨酰胺合成酶（GS）的酶活性维持在较高水平。此外，植物生长调节剂和氮肥的施用提高了GS、谷氨酸脱氢酶（GDH）和谷丙转氨酶（GPT）的酶活性以及谷物中粗蛋白、赖氨酸、蔗糖和可溶性糖的含量，最终提高了玉米产量。本研究表明，施用N200并结合化学调控可促进根系活力和养分积累，并能提高高密度种植条件下的谷物产量和品质。
