IMPACT OF POLYETHYLENE GLYCOL-INDUCED OSMOTIC STRESS ON MAIZE GERMINATION, GROWTH, AND PHYSIOLOGICAL RESPONSE

Abstract

Drought stress is a significant environmental concern affecting crop growth, development, and yield. A laboratory experiment was conducted to examine the germination characteristics of four maize genotypes under varying levels of osmotic stress (0%, 2.5%, 5%, 7.5%, 10%) using polyethylene glycol (PEG) 6000 as an osmoticum. The experiment followed a factorial design within a Completely Randomized Design (CRD) framework with three replications. Varying concentrations of PEG influenced the germination and early growth of plants. An interesting finding was that as the concentration of PEG increased, there was a noticeable decrease in plant growth, indicating a negative correlation between the two. The findings indicated that subjecting maize plants to water stress treatments significantly affected various growth parameters (with a statistical significance level of P<0.05). Furthermore, with the increase in PEG concentration, there was a gradual decline in both respiration and transpiration rates, resulting in a decrease in protein concentration. There is a significant decrease in relative water content (RWC) in both shoot and root by 28.65% and 11.13%, respectively, compared with the control. When maize seedlings were subjected to water deficit by treating them with 2.5 to 10% PEG, there was a significant decrease (by 60.05%) in the level of chlorophyll 'b' while the decrease (by 33.25%) in chlorophyll 'a' content was comparatively less pronounced.