Premium
Increased Maize Plant Population Induced Leaf Senescence, Suppressed Root Growth, Nitrogen Uptake, and Grain Yield
Author(s) -
Li Rongfa,
Liu Peng,
Dong Shuting,
Zhang Jiwang,
Zhao Bin
Publication year - 2019
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2018.09.0554
Subject(s) - senescence , population , agronomy , nitrogen , biomass (ecology) , yield (engineering) , grain yield , field experiment , plant physiology , poaceae , biology , chemistry , horticulture , botany , organic chemistry , sociology , metallurgy , microbiology and biotechnology , materials science , demography
Core Ideas Increased maize plant population induced leaf senescence, especially lower leaf. Senescence of lower leaves could significantly decrease the distribution of C to the root system, root activity weakened, reducing the uptake of nitrogen. Senescence of lower leaves decreased the accumulation of biomass, resulting in lower yield.To date, little attention has been paid to the effects of lower position leaves on root function and N uptake in maize. This study was conducted to analysis the relationship between lower leaf senescence and root function in different plant population (67,500 plants ha −1 , 90,000 plants ha −1 ). We used the maize varieties DengHai661 (DH661) and ZhengDan958 (ZD958) in field and soil column experiments to unravel this physiological puzzle. The field experiment evaluated their effects on N accumulation and grain yield. Relative to the low plant population, the high plant population reduced leaf area (52.6–69.2%), and the root biomass (25.5–31.8%) per plant. Grain weight and the number of grains per ear were also negatively affected. Biomass and grain yield generally increased ( P < 0.05) with increasing plant population. The grain yield of DH661 and ZD958 increased by 8.1% and 10.1% in 2015, and 7.5% and 13.0% in 2016, respectively. The N accumulation of two varieties post‐silking decreased. In the soil column experiments, we found that lower leaf senescence suppressed root growth, N uptake, and altered N partition, thereby decreasing green leaf area and ultimately affecting grain yield. Grain yield in DH661 and ZD958 decreased by 5.8 and 8.6%, respectively. Our results suggest that delaying lower leaf senescence in high plant population would be conducive to maintaining the N‐uptake ability of roots, higher canopy photosynthetic capacity, and the building of grain sink to obtain higher yields.