Maize seedlings response to drought stress and re-watering: abscisic acid, a key regulator of physio-biochemical traits and gas exchange parameters

摘要

A pot-culture study was conducted to estimate the role of abscisic acid (ABA) and its regulatory mechanisms in maize seedlings to adapt water deficit and re-watering conditions. The maize seedlings ( Zea mays L.) were exposed to well-watered, water deficit and re-watering conditions at seedling stage. Results showed that ABA concentration was significantly increased 1.97-fold and 1.73-fold ( p 0.01) under moderate and severe drought stress conditions, respectively. Moreover, drought stress significantly increased the activities of antioxidant enzymes (SOD, POD and CAT), and the concentration of MDA and O 2 - . The photosynthetic rate ( P n), stomatal conductance ( g s ), and transpiration rate ( E ) in leaves were decreased by withholding water for 2 days. Our study demonstrated that the plants physio-biochemical traits and gas exchange parameters variation under drought probably were caused by a higher level of ABA. The shoot biomass was reduced by 34.4% and 66.1% and the root biomass was reduced by 44% and 69% under moderate and severe drought stress treatments, respectively. Results showed that the root biomass had more reduction under drought stress treatments, indicating that water deficit affected plants biomass allocation patterns. We conclude that ABA plays an important role in regulating the plant growth under drought stress and re-watering conditions, and improve the osmotic adjustment for plant better growth and development.