Alleviation of Water Stress Effects on MR220 Rice by Application of Periodical Water Stress and Potassium Fertilization

Nurul Zain,Mohd Ismail,Adam Puteh,Maziah Mahmood,Mohd Ibrahim

doi:10.3390/molecules19021795

Nurul Zain, Mohd Ismail + Show 3 more

Open Access

https://doi.org/10.3390/molecules19021795

Copy DOI

Abstract

The use of periodical water stress and potassium fertilization may enhance rice tolerance to drought stress and improve the crop’s instantaneous water use efficiency without much yield reduction. This study was conducted to assess the effects of different periodical water stress combined with potassium fertilization regimes on growth, yield, leaf gas exchanges and biochemical changes in rice grown in pots and compare them with standard local rice grower practices. Five treatments including (1) standard local grower’s practice (control, 80CF = 80 kg K2O/ha + control flooding); (2) 120PW15 = 120 kg K2O/ha + periodical water stress for 15 days; (3) 120DS15V = 120 kg K2O/ha + drought stress for 15 days during the vegetative stage; (4) 120DS25V = 120 kg K2O/ha + drought stress for 25 days and (5) 120DS15R = 120 kg K2O/ha + drought stress for 15 days during the reproductive stage, were evaluated in this experiment. Control and 120PW15 treatments were stopped at 100 DAS, and continuously saturated conditions were applied until harvest. It was found that rice under 120PW15 treatment showed tolerance to drought stress evidenced by increased water use efficiency, peroxidase (POX), catalase (CAT) and proline levels, maximum efficiency of photosystem II (fv/fm) and lower minimal fluorescence (fo), compared to other treatments. Path coefficient analysis revealed that most of parameters contribute directly rather than indirectly to rice yield. In this experiment, there were four factors that are directly involved with rice yield: grain soluble sugar, photosynthesis, water use efficiency and total chlorophyll content. The residual factors affecting rice yield are observed to be quite low in the experiment (0.350), confirming that rice yield was mostly influenced by the parameters measured during the study.

Highlights

Drought is an abiotic stress, and it affects plants at various levels of their organization
The aim of the present work was to evaluate the effect of periodical water stress and potassium fertilization regimes on drought stress tolerance-related parameters (growth and yield, leaf gas exchange, chlorophyll fluorescence, the anti-oxidative enzymes (CAT and POX), soluble sugars, proline, and lipid peroxidation responses)
The results indicated that the tested management practices influenced the yield and all the growth components (p ≤ 0.01; Table 1)

Summary

Introduction

Drought is an abiotic stress, and it affects plants at various levels of their organization. Drought affects plant-water relations through the reduction of water content, turgor and total water, but it affects stomatal closure, limits gaseous exchange, reduces transpiration and arrests carbon assimilation (photosynthesis) rates [2]. Plant responses to drought are complex and several different mechanisms are adopted by plants when they encounter drought [3,4], including: (i) drought escape by rapid development which allows plants to finish their cycle before severe water stress; (ii) drought avoidance by, for instance, increasing water uptake and reducing transpiration rate by the reduction of stomatal conductance and leaf area; (iii) drought tolerance by maintaining tissue turgor during water stress via osmotic adjustment which allows plants to maintain growth under water stress, and (iv) resisting severe stress through other survival mechanisms [3]

Objectives

Results

Conclusion