Ethylene Inhibitors Increase Net Assimilation Rate and Cotton Boll Dry Matter Under Drought

Giovani Greigh De Brito,Ana Luiza Dias Coelho Borin,Alexandre Cunha De Barcelos Ferreira

doi:10.5539/jas.v6n10p197

Abstract

Although the ethylene inhibitors role on reduction rate of boll abscission in cotton plants submitted to drought is being recently reported, its effects on photosynthesis performance and on cotton boll dry matter across the sympodial branch is scarce. Thus, the objective of this study was to evaluate the cotton photosynthesis and its boll dry matter performance across the reproductive branches via positional mapping in plants sprayed with ethylene inhibitors and submitted to water deficit. 1-methylcyclopropene (1-MCP), an inhibitor of ethylene action and aminoethoxyvinylglycine (AVG), an inhibitor of its synthesis, were sprayed on cotton plants alone and in association. Treatments were composed by (T1) control, where deionized water was sprayed; (T2) sprayed with AVG at 0.15 g a.i. L-1; (T3) 1-MCP at 0.076 g a.i. L-1; (T4) AVG at 0.15 g a.i. L-1 plus 1-MCP at 0.076 g a.i. L-1; (T5) AVG at 0.15 g a.i. L-1 twice at each seven days; (T6) 1-MCP sprayed at 0.076 g a.i. L-1 twice using the same interval and (T7) AVG at 0.15 g a.i. L-1 plus 1-MCP at 0.076 g a.i. L-1 twice at each seven days. The ethylene inhibitors sustained higher photosynthesis performance and higher boll dry mass across reproductive branches independent of compound, its combination or entries number. Highlight that a AVG (T2) or its 1-MCP association in two entries (T7) showed the best performance for dry matter accumulation, especially in the two first reproductive branches, while they maintained the highest photosynthesis rates at the end of stress period.

Highlights

Abiotic and biotic stresses represent the major constraints that result in agricultural losses on the global scale, and projected climate changes could increase their negative effects in the future (IPCC, 2007; Fischer & Schar, 2010).Cotton (Gossypium hirsutum L. r. latifolium) is the major fiber crop; cotton yields are often limited due to the extreme sensitivity of this crop to environmental stressors, such as temperature variation and drought events, so that cotton plants are continuously exposed to various biotic and abiotic stresses during growth in their natural environment
To gain more comprehensive knowledge in this respect, the objective of this research was to evaluate the performance of cotton boll dry mass across the reproductive branches via positional mapping and characterize its photosynthesis responses when sprayed with ethylene inhibitors and submitted to water deficit regime
Gas exchange analysis of untreated control with ethylene inhibitors and submitted to stress showed a photosynthesis decline of 24.6% at the end of stress period compared to those sprayed with these compounds independent of combinations and its entries number

Summary

Introduction

Abiotic and biotic stresses represent the major constraints that result in agricultural losses on the global scale, and projected climate changes could increase their negative effects in the future (IPCC, 2007; Fischer & Schar, 2010).Cotton (Gossypium hirsutum L. r. latifolium) is the major fiber crop; cotton yields are often limited due to the extreme sensitivity of this crop to environmental stressors, such as temperature variation and drought events, so that cotton plants are continuously exposed to various biotic and abiotic stresses during growth in their natural environment. Latifolium) is the major fiber crop; cotton yields are often limited due to the extreme sensitivity of this crop to environmental stressors, such as temperature variation and drought events, so that cotton plants are continuously exposed to various biotic and abiotic stresses during growth in their natural environment Under such conditions, cotton plants can evoke intricate mechanisms to perceive external signals, allowing the optimal response to the environmental conditions. Cotton plants can evoke intricate mechanisms to perceive external signals, allowing the optimal response to the environmental conditions As components of these mechanisms, plant hormones, including abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA) and ethylene (ET), are endogenous, low molecular weight molecules that primarily regulate the protective responses of plants against both biotic and abiotic stresses via synergistic and antagonistic actions, which are referred to as signaling crosstalk (Fujita et al, 2006). A common response of cotton plants when submitted to stress is its increased ethylene biosynthesis; and this comportment is very well established and its role in the regulation of the abscission process in cotton fruit is extensively reported, the relationship of www.ccsenet.org/jas

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