Abstract

Intraspecific competition for light affects nutrient uptake of maize, especially during the seed filling phase (from the blistering-stage to physiological-maturity). Partial leaf removal only affects the top leaves and improves the light-environment, which could then enhance nutrient uptake during the seed filling phase. However, there is a shortage of quantitative information on the yield effects of such a management measure. A 3-year field trial was conducted to evaluate the impact of different leaf removal treatments (no removal of leaves (D0: control), removal of two leaves (D2), removal of four leaves (D4), and removal of six leaves (D6) from maize-canopy) on total dry matter accumulation, and nitrogen, phosphorus, and potassium uptake at the blistering-stage and physiological-maturity, plus seed number per plant, seed weight, and seed yield at physiological maturity. Compared to D0, at physiological-maturity, D2 significantly increased total dry matter accumulation (by 9%), and uptake of nitrogen (by 5%), phosphorus (by 10%), and potassium (by 4%); while excessive leaf removal treatments considerably reduced dry matter accumulation and nutrient uptake. Importantly, during the seed filling phase of maize, treatment D2 significantly enhanced the uptake of nitrogen, phosphorus, and potassium by 76%, 40%, and 65%, respectively, compared to control. Treatment D2 increased seed number per plant (by 6.4%, from 448 under D0 to 477 in D2) and seed weight (by 5.7%). Relative to control, maize in D2 had 12%, 14%, and 11%, higher seed-yields in 2017, 2018, and 2019, respectively, and it also improved the economic profit when taking into account labor costs.

Graphic abstract

Graphical representation of changes in light transmittance, photosynthesis, nutrient uptake, carbohydrate, and dry matter accumulation in maize plants as affected by different leaf removal treatments. Treatment codes represent no defoliation (D0: control), removal of two leaves (D2), removal of four leaves (D4), and removal of six leaves (D6) from the top of maize canopy. Yellow and green arrows show the light environment and leaf area of maize plants. The black arrows represent the regulating directions of leaf removal treatments on maize growth and development in this paper. The graphical abstract clearly demonstrates the significant improvement of optimum leaf removal treatment (D2) as compared to control (D0). The red and blue arrows show the relevant increase and decrease of the mentioned components between the optimal leaf removal and control.

中文翻译：

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去除顶叶可增加玉米植物的产量和养分吸收

摘要

种内对光的竞争会影响玉米的养分吸收，尤其是在种子填充阶段（从起泡阶段到生理成熟）。去除部分叶子只会影响顶叶并改善光照环境，从而可以在种子填充阶段提高养分吸收。但是，关于这种管理措施的产量影响，缺乏定量信息。进行了为期三年的田间试验，以评估不同的除叶处理（不除叶（D0：对照），除两叶（D2），除四叶（D4）和除六叶（D0：对照）的影响。 D6）来自玉米冠层）的总干物质积累以及起泡期和生理成熟期的氮，磷和钾吸收量，以及单株种子数，种子重量，和生理成熟时的种子产量。与D0相比，在生理成熟时，D2显着增加了总干物质积累（增加了9％），并吸收了氮（增加了5％），磷（增加了10％）和钾（增加了4％）；而过多的除叶处理则大大减少了干物质的积累和养分的吸收。重要的是，在玉米的种子填充阶段，与对照相比，处理D2显着提高了氮，磷和钾的吸收量，分别为76％，40％和65％。处理D2使每株植物的种子数增加了6.4％，从D0下的448增加到D2中的477），种子重量增加了5.7％。相对于控制而言，D2的玉米在2017年，2018年和2019年的种子产量分别增加了12％，14％和11％，并且在考虑人工成本的情况下也提高了经济利润。

图形摘要

受不同脱叶处理影响的玉米植株的透光率，光合作用，养分吸收，碳水化合物和干物质积累的变化的图形表示。处理代码表示不脱叶（D0：对照），除去两片叶子（D2），除去四片叶子（D4）以及从玉米冠层顶部除去六片叶子（D6）。黄色和绿色箭头表示玉米植物的光照环境和叶面积。黑色箭头代表了脱叶处理对玉米生长发育的调控方向。图形摘要清楚地表明，与对照（D0）相比，最佳除叶处理（D2）有了显着改善。