Synergistic effects of planting density and nitrogen fertilization on chlorophyll degradation and leaf senescence after silking in maize
Tianqiong Lan,
Lunjing Du,
Xinglong Wang,
Xiaoxu Zhan,
Qinlin Liu,
Gui Wei,
Chengcheng Lyu,
Fan Liu,
Jiaxu Gao,
Dongju Feng,
Fanlei Kong,
Jichao Yuan
Affiliations
Tianqiong Lan
Key Laboratory of Crop Physiology, Ecology, and Cultivation Southwest, Ministry of Agriculture, Sichuan Agricultural University, Chengdu 611130, Sichuan, China; College of Agronomy, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
Lunjing Du
Chongqing Academy of Agricultural Sciences, Chongqing 401329, China; College of Agronomy, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
Xinglong Wang
Key Laboratory of Crop Physiology, Ecology, and Cultivation Southwest, Ministry of Agriculture, Sichuan Agricultural University, Chengdu 611130, Sichuan, China; College of Agronomy, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
Xiaoxu Zhan
College of Agronomy, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
Qinlin Liu
College of Agronomy, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
Gui Wei
College of Agronomy, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
Chengcheng Lyu
College of Agronomy, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
Fan Liu
College of Agronomy, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
Jiaxu Gao
College of Agronomy, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
Dongju Feng
Key Laboratory of Crop Physiology, Ecology, and Cultivation Southwest, Ministry of Agriculture, Sichuan Agricultural University, Chengdu 611130, Sichuan, China; College of Agronomy, Sichuan Agricultural University, Chengdu 611130, Sichuan, China
Fanlei Kong
Key Laboratory of Crop Physiology, Ecology, and Cultivation Southwest, Ministry of Agriculture, Sichuan Agricultural University, Chengdu 611130, Sichuan, China; College of Agronomy, Sichuan Agricultural University, Chengdu 611130, Sichuan, China; Corresponding authors.
Jichao Yuan
Key Laboratory of Crop Physiology, Ecology, and Cultivation Southwest, Ministry of Agriculture, Sichuan Agricultural University, Chengdu 611130, Sichuan, China; College of Agronomy, Sichuan Agricultural University, Chengdu 611130, Sichuan, China; Corresponding authors.
Regulating planting density and nitrogen (N) fertilization could delay chlorophyll (Chl) degradation and leaf senescence in maize cultivars. This study measured changes in ear leaf green area (GLAear), Chl content, the activities of Chl a-degrading enzymes after silking, and the post-silking dry matter accumulation and grain yield under multiple planting densities and N fertilization rates. The dynamic change of GLAear after silking fitted to the logistic model, and the GLAear duration and the GLAear at 42 d after silking were affected mainly by the duration of the initial senescence period (T1) which was a key factor of the leaf senescence. The average chlorophyllase (CLH) activity was 8.3 times higher than pheophytinase activity and contributed most to the Chl content, indicating that CLH is a key enzyme for degrading Chl a in maize. Increasing density increased the CLH activity and decreased the Chl content, T1, GLAear, and GLAear duration. Under high density, appropriate N application reduced CLH activity, increased Chl content, prolonged T1, alleviated high-density-induced leaf senescence, and increased post-silking dry matter accumulation and grain yield.
