Changes in Leaf Structure and Chemical Compositions Investigated by FTIR Are Correlated with Different Low Potassium Adaptation of Two Cotton Genotypes

Xiuwen Wu,Muhammad Riaz,Yanshu Hao,Cuncang Jiang

doi:10.3390/agronomy10040479

Abstract

Potassium (K) is an essential macronutrient for plant growth and development. K deficiency seriously affects protein and carbohydrate synthesis in the leaves of plants. The present study was carried out with two cotton genotypes with low K tolerance to investigate the different changes on chemical composition and structure in leaves of K-efficient cotton genotypes under low K stress by using Fourier transform infrared spectroscopy (FTIR) technology. The results showed that K deficiency decreased the leaf photosynthetic pigments in both genotypes, but significant observations were noted in K-efficient genotype 103. FTIR spectra and semiquantitative analysis revealed that the cell membrane permeability, cell wall pectin, protein, and polysaccharides of leaves were greatly influenced by K deficiency, and the changes were more significant in the leaf of genotype 122, indicating a better adaptation to low K in genotype 103. The results of this study revealed that the difference of low K adaptation of these two cotton genotypes might be related to maintaining cell wall integrity and carbohydrate transport in cells. These different compositional and structural changes in the leaves of the two cotton genotypes under K-deficient level gain a new physiological mechanism of K efficiency in cotton.

Highlights

Potassium (K) is an essential mineral nutrient for normal growth and development of higher plants [1]
The results indicated that K deficiency has a more significant effect on protein structure and cellulose in the functional leaves, while it does not decrease carbohydrates in
Our Fourier transform infrared spectroscopy (FTIR) spectra showed the decreased intensities of vibrations in 1650, 1550, 1436, and 1244 cm−1 were associated with protein and its structure (Table 2), implying that K deficiency stress seriously influenced the protein synthesis and structure of both cotton genotypes

Summary

Introduction

Potassium (K) is an essential mineral nutrient for normal growth and development of higher plants [1]. It is widely accepted that K plays a vital role in activating the enzyme system, maintaining photosynthesis, and promoting translocation of photosynthate [2]. A high concentration of K+ is required for optimal protein synthesis and photosynthesis [3]. K, the majority of K+ in soils is either dehydrated or attached to oxygen atoms and is unavailable for plants. Chemical fertilizer is mandatory to ensure an adequate supply of available K to crops in intensive agriculture. The K fertilizer demand in the world is projected to further increase from 23.8 million tons (Mt) in 2011 to 27.1

Methods

Findings

Discussion

Conclusion