Equal potassium-nitrogen ratio regulated the nitrogen metabolism and yield of high-density late-planted cotton (Gossypium hirsutum L.) in Yangtze River valley of China

et al. 2020

J Soil Sci Plant Nutr

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Potassium (K) plays a pivotal role in carbon (C) and nitrogen (N) balance via several physiological processes. Conventional K application ratio (0.6-0.8) is too low to meet the optimal K requirement for physiological activities as well as yield benefits in cotton. However, in line with low N application, what is the optimal K ratio relative to N, for efficient C-N balance and its relationship with enzymes activities as well as yield, is the objective of this study. A pot experiment was conducted with three K ratio to N (K 1 (0.8), K 2 (1.0), and K 3 (1.2)) using completely randomized design at the experimental site of Huazhong Agricultural University, Wuhan, China. The morphological attributes, C-N enzyme activities, assimilate contents, and yieldrelated components were analyzed under different K ratios. Results showed that higher K application ratios (K 2 and K 3) significantly enhanced the yield, leaf morphological attributes (leaf area and leaf weight), and C-and N-metabolizing enzyme activities. Similarly, C and N assimilation compounds were effectively balanced in leaves of plants receiving K 2 and K 3 over K 1 leading to an appropriate C/N ratio. Conclusively, leaf K content, C-N compounds balance, and narrow C/N ratio in higher K application suggest that the K relative ratio should be equal or even higher than N application rate. However, from an economic point of view, results suggest that the K ratio equal to the N is sufficient to get promising cotton yield with late planting under reducing N rate.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Relative Potassium Ratio Balanced the Carbon-Nitrogen Assimilation in Cotton Leaf Under Reducing Nitrogen Application

Ali

et al. 2020

J Soil Sci Plant Nutr

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“…Higher K fertilizer amounts (K 2 and K 3 ) increased 10.34%-20.03% seed cotton yield over K 1 due to higher boll density in 2016 and boll weight in both years, although differences existed between years in yield and its components [26,27].…”

Section: Discussionmentioning

confidence: 99%

“…The mean air temperatures from May to October in 2016 were 25.4 • C with 0.1 • C lower than that in 2017, and from June to September, air temperatures in 2016 were 0.3-1.6 • C lower than that in early 2017. The total rainfall from May to October in 2016 was 1311.6 mm with 925 mm more than that in 2017, and rainfall was mainly concentrated on June and July in 2016 with 823 mm more than that in 2017, but 107 mm less from August to September in 2016 than in 2017 [26].…”

Section: Climatementioning

confidence: 91%

Equal K Amounts to N Achieved Optimal Biomass and Better Fiber Quality of Late Sown Cotton in Yangtze River Valley

Ali

et al. 2020

Agronomy

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Potassium (K) fertilizer plays a crucial role in the formation of the biological and economic yield of cotton (Gossypium hirsutum L.). Here we investigated the effects of the amount of K on biomass accumulation and cotton fiber quality with lowered N amounts (210 kg ha−1) under late sowing, high density and fertilization once at 2 weeks after squaring. A 2-year field experiment was performed with three K fertilizer amounts (168 kg ha−1 (K1), 210 kg ha−1 (K2), and 252 kg ha−1 (K3)) using a randomized complete block design in 2016 and 2017. The results showed correspondingly, K3 accumulated cotton plant biomass of 7913.0 kg ha−1, next to K2 (7384.9 kg ha−1) but followed by K1 (6985.1 kg ha−1) averaged across two growing seasons. Higher K amounts (K2, K3) increased biomass primarily due to a higher accumulation rate (32.68%–74.02% higher than K1) during the fast accumulation period (FAP). Cotton fiber length, micronaire, and fiber strength in K2 were as well as K3 and significantly better than K1. These results suggest that K fertilizer of 210 kg ha−1 should be optimal to obtain a promising benefit both in cotton biomass and fiber quality and profit for the new cotton planting model in the Yangtze River Valley, China and similar climate regions.

“…Chlorophyll is the most important attribute of Pn as it reflects the level of Pn in the plants (Ali et al 2019). Tung et al (2018b) reported that MC-treated cotton usually have thick "leathery" leaves with higher chlorophyll contents.…”

Section: Physiological Aspects Of Mepiquat Chloride Application In Comentioning

confidence: 99%

Morpho-physiological Effects and Molecular Mode of Action of Mepiquat Chloride Application in Cotton: A Review

Tung

Huang

et al. 2020

J Soil Sci Plant Nutr

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Mepiquat chloride (MC) (1,1-dimethylpiperidinum chloride) is a plant growth regulator, usually sprayed on cotton foliage at different growth stages as a practical tool for cotton management. MC foliar applications reduce plant height, leaf area, node distance, and plant canopy but increase light interception within the canopy that leads to increase yields. Application at squaring stage reduces the partitioning of photoassimilates towards main stem, branches, and growing points but increases partitioning to the reproductive organs. Furthermore, MC application increases the net photosynthesis rate in cotton leaves as compared with control and triggers carbohydrate formation by improved source-sink relationship. Disturbed carbohydrate metabolism could affect the activity of sucrose metabolic enzymes resulted in variable yield responses. More precisely, it retards the vegetative growth by inhibiting the activity of gibberellin involved in cell elongation, which inhibits the signaling pathways and disturbs gibberellin homeostasis by upregulation of site-specific genes that ultimately results in keeping the plant stature shorter. Besides this, it enhances the yield due to raised boll setting on the lower branches by manipulating a compact canopy. This review will focus on cotton morphology and yield responses to MC application that have been published in last decades. Various physiological mechanisms such as carbohydrate metabolism and sucrose-related enzymes as well as its molecular mode of action in cotton have also been discussed. Further research is needed to exploit the role of MC specifically in gibberellin inhibition and carbohydrate metabolism with its related enzymes. Keywords Cotton. Mepiquat chloride. Morpho-physiological response. Molecular approach. Yield Abbreviations MC Mepiquat chloride PGRs Plant growth regulators GA Gibberellin Pn Net photosynthesis Rubisco Ribulose 1,5-bisphosphate carboxylase oxygenase SPS Sucrose phosphate synthase SS Sucrose synthase SAI Soluble acid invertase NI Neutral invertase UDPG Uridine diphosphate glucose a.i Active ingredient