Cultivar sensitivity of broomcorn millet (Panicum miliaceum L.) to nitrogen availability is associated with differences in photosynthetic physiology and nitrogen uptake.

Yan Luo, Chunjuan Liu, Ke Dang, Xiangwei Gong, Baili Feng

Plant physiology and biochemistry : PPB 2022 Jul 01

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In order to explore the influences of low nitrogen (N) fertilizer on the growth performances of two broomcorn millet (Panicum miliaceum L.) cultivars with different N tolerances, the field experiment was carried out with a low-N-tolerant cultivar (BM 184) and a low-N-sensitive cultivar (BM 230) under three N levels (0, 75 and 150 kg N ha-1) in the Loess Plateau, China. 150 kg N ha-1 was conventional N application rate and considered as the control. Compared to typical N supply, low N fertilizer significantly weakened the photosynthetic capacity by increasing the light transmission ratio and decreasing leaf area index, resulting in reduced biomass accumulation. BM 184 held the longer duration of the biomass increase phase and larger relative growth rate than BM 230 as well as higher photosynthetic parameters (i.e., relative chlorophyll content, net photosynthetic rate, and transpiration rate) did under low N treatments. Such optimized physiological characteristics contributed to more effective N uptake and transportation from the stems, leaves, and sheaths to grains in the BM 184. Furthermore, compared with BM 230, BM 184 had higher rhizosphere soil fertility and soil enzyme activity under low N conditions; consequently, combined with the physiological characteristics for aboveground and soil nutrient status for belowground, higher productivity was obtained in BM 184 than that in BM 230 over the two years study. Overall, our results demonstrated that low-N-tolerant cultivar achieved reduced N fertilizer input with increased efficiency by optimizing growth performances in semi-arid cultivation areas. Copyright © 2022 Elsevier Masson SAS. All rights reserved.

Citation

Yan Luo, Chunjuan Liu, Ke Dang, Xiangwei Gong, Baili Feng. Cultivar sensitivity of broomcorn millet (Panicum miliaceum L.) to nitrogen availability is associated with differences in photosynthetic physiology and nitrogen uptake. Plant physiology and biochemistry : PPB. 2022 Jul 01;182:90-103