Morphological and physiological response of maize seedlings to chilling stress

Abstract

Although accompanied with adverse low temperatures, early maize sowing could be used to avoid drought during flowering and diminish yield losses. Herein, a small-scale experiment of low temperature stress (LTS) on maize lines L1 (tolerant), L2 (medium tolerant) and L3 (susceptible) is presented. Plants were grown in pots exposed to exterior suboptimal (March) and optimal (late April) temperatures until three leaf stage. Chlorophyll (CH), flavonoids (FL), anthocyanins (AN) and nitrogen balance (NBI) indices were measured using Dualex Scientific optical device. Growth parameters were also determined. Under LTS, number of plants was unchanged for L1 and halved for L2 and L3. Compared to L2 and L3, L1 had significantly higher (p<0.05) shoot fresh weight (0.649 g vs. 0.406 g and 0.303 g), AN (0.17 vs. 0.13) and FL (1.47 vs. 1.38 and 1.36). For recovery evaluation, plants were transplanted into the field. Transplanted stressed L1 plants showed the highest grain yield per plant (55g) in the field. Due to high correlations (p<0.01) between FL in three leaf stage and grain yield per plant, FL could be used as an indicator of plant recovery of maize genotypes exposed to LTS during early sowing.