Drought Induced Changes in Growth, Osmolyte Accumulation and Antioxidant Metabolism of Three Maize Hybrids

Abstract

Consequences of drought stress in crop production systems are perhaps more deleterious than other abiotic stresses under changing climatic scenarios. Regulations of physio-biochemical responses of plants under drought stress can be used as markers for drought stress tolerance in selection and breeding. The present study was conducted to appraise the performance of three different maize hybrids (Dong Dan 80, Wan Dan 13, and Run Nong 35) under well-watered, low, moderate and SD conditions maintained at 100, 80, 60, and 40% of field capacity, respectively. Compared with well-watered conditions, drought stress caused oxidative stress by excessive production of reactive oxygen species (ROS) which led to reduced growth and yield formation in all maize hybrids; nevertheless, negative effects of drought stress were more prominent in Run Nong 35. Drought-induced osmolyte accumulation and strong enzymatic and non-enzymatic defense systems prevented the severe damage in Dong Dan 80. Overall performance of all maize hybrids under drought stress was recorded as: Dong Dan 80 > Wan Dan 13 > Run Nong 35 with 6.39, 7.35, and 16.55% yield reductions. Consequently, these biochemical traits and differential physiological responses might be helpful to develop drought tolerance genotypes that can withstand water-deficit conditions with minimum yield losses.

Keywords: ROS; agronomic traits; antioxidant defense; drought; maize; yield formation.

FIGURE 1

Influence of different drought stress levels on the production of (A) malenoaldehyde (MDA), (B) superoxide anion (O₂^.-), (C) hydrogen peroxide (H₂O₂), (D) thiobarbituric acid reactive substances (TBARS), (E) electrolyte leakage (EL), and (F) lipoxygenase (LOX) in three maize hybrids. Capped bars above means represent ±SE of three replicates. Small alphabetical letters above means denote the significant differences among treatment with in a maize hybrid at P ≤ 0.05. Ck, control (100% FC); LD, low drought (80% FC); MRD, moderate drought (60% FC); and SD, severe drought (40% FC); FC, Field capacity.

FIGURE 2

Influence of different drought stress levels on the accumulations of (A) free proline, (B) total carbohydrates, (C) soluble sugars, (D) phenolic contents, (E) soluble protein, and (F) total free amino acids in three maize hybrids. Capped bars above means represent ±SE of three replicates. Small alphabetical letters above means denote the significant differences among treatment with in a maize hybrid at P ≤ 0.05. Ck, control (100% FC); LD, low drought (80% FC); MRD, moderate drought (60% FC); and SD, severe drought (40% FC); FC, Field capacity.

FIGURE 3

Influence of different drought stress levels on the activities of (A) superoxide dismutase (SOD), (B) peroxidase (POD), (C) catalase (CAT), (D) Ascorbate peroxidase (APX), (E) Dehydroascorbater eductase (DHAR), and (F) monodehydroascorbater eductase (MDHAR) in three maize hybrids. Capped bars above means represent ±SE of three replicates. Small alphabetical letters above means denote the significant differences among treatment with in a maize hybrid at P ≤ 0.05. Ck, control (100% FC); LD, low drought (80% FC); MRD, moderate drought (60% FC); and SD, severe drought (40% FC); FC, Field capacity.

FIGURE 4

Influence of different drought stress levels on (A) ascorbic acid (AsA), (B) reduced glutathione (GSH), (C) dehydroascorbate (DHA), (D) oxidized glutathione (GSSG) in three maize hybrids. Small alphabetical letters above means denote the significant differences among treatment with in a maize hybrid at P ≤ 0.05. Capped bars above means represent ±SE of three replicates. Ck, control (100% FC); LD, low drought (80% FC); MRD, moderate drought (60% FC); and SD, severe drought (40% FC); FC, Field capacity.