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

Abstract

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

Impact of Growth Retardant and Defoliant on Morpho-physiological Traits and Yield Improvement in Cotton

“…Application of MC improved the yield of cotton crop and also improves the fibre quality [5]. In comparison to MC application at 50 DAS, MC application at 70 DAS improved seed cotton yield plant -1 (23%) and ultimate cotton yield (23%) [30].…”

“…Cotton canopy management by MC is the one of the tactics used in agriculture to enhance the yield of cotton. MC application altered the plant canopy and increased the cotton yield by increasing air flow [5]. Because of the limited boll setting %, increase in plant density reduced boll weight, lint yield, and no.…”

Mepiquat chloride inhibits soybean growth but improves drought resistance

“…Spraying DPC on leaves also reduced plant height, leaf area, asphalt, and canopy, increasing light interception in the canopy, thereby increasing yield. In recent study, DPC was mainly used in cotton production and formed a relatively complete system ( Tung et al, 2020 ). However, DPC has also been applied to other crops.…”

The effects of mepiquat chloride (DPC) on the soluble protein content and the activities of protective enzymes in cotton in response to aphid feeding and on the activities of detoxifying enzymes in aphids

“…DPC enhanced cotton resistance through a variety of ways. For example, DPC enhances cotton resistance by promoting root growth [ 43 , 44 ]. Furthermore, DPC enhances photosynthesis in cotton leaves by increasing the chlorophyll content, photosynthetic rate, and the relative chlorophyll content (SPAD value) [ 25 , 26 ].…”