Analysis of Growth and Physiological Characteristics of Maize under Salinity Stress and its Mitigation by Seed Priming with Thiourea

Improved Salinity Tolerance in Maize by Thiourea

Abstract

Background: Among the many abiotic stresses, salinity stress is the most pervasive one. It affects plant productivity by altering the physiological phenomena. The seed priming strategy has proved of great significance in reducing the salinity stress effects. Thiourea has been least investigated for its specific physiological effects in improving salinity stress tolerance in plants.

Objectives: The purpose of this study was to explore the role of thiourea seed priming on the physiological and biochemical basis of salinity tolerance in hybrid maize (Zea mays L.) at early growth stage.

Methodology: The seed of maize hybrid Ujala were unsoaked, soaked in water (hydro-primed) and 400 µM thiourea (thiourea primed) and sown in plastic pots containing 5 kg of loam soil. After 28 days of growth, the increased salinity treatment (0, 50, 75 and 100 mM) were applied in installments of 25 mM per day. The plants were grown for 24 days after salinity treatment application. The data were recorded for different morphological and biochemical parameters using standard analytical procedures.

Results: Salinity stress adversely affected both physiological and growth attributes due to causing oxidative damage to cellular membranes, ion-toxicity and induced water deficit. However, thiourea primed plants manifested greater salinity tolerance in maize as compared to control and hydro-primed plants by showing improvements in photosynthetic pigments, osmoprotectants, vitamins and phenolic compounds. This was due to the defined role of thiourea to reduce oxidative damage and provide nitrogen nutrition by virtue of the presence of thiol, amino and imino groups in its molecule.

Conclusion: Seed priming with thiourea emerged to be an effective strategy for alleviating salinity stress in hybrid maize due to biological effects. The results suggested that thiourea seed priming can be effectively used to obtain improved maize growth in marginally to moderately salinity-hit areas.