title: Genotypic Variation in Growth and Physiological Response to Drought Stress and Re-Watering Reveals the Critical Role of Recovery in Drought Adaptation in Maize Seedlings.
abstract: Non-irrigated crops in temperate climates and irrigated crops in arid climates are subjected to continuous cycles of water stress and re-watering. Thus, fast and efficient recovery from water stress may be among the key determinants of plant drought adaptation. The present study was designed to comparatively analyze the roles of drought resistance and drought recovery in drought adaptation and to investigate the physiological basis of genotypic variation in drought adaptation in maize (Zea mays) seedlings. As the seedlings behavior in growth associate with yield under drought, it could partly reflect the potential of drought adaptability. Growth and physiological responses to progressive drought stress and recovery were observed in seedlings of 10 maize lines. The results showed that drought adaptability is closely related to drought recovery (r = 0.714(**)), but not to drought resistance (r = 0.332). Drought induced decreases in leaf water content, water potential, osmotic potential, gas exchange parameters, chlorophyll content, Fv/Fm and nitrogen content, and increased H2O2 accumulation and lipid peroxidation. After recovery, most of these physiological parameters rapidly returned to normal levels. The physiological responses varied between lines. Further correlation analysis indicated that the physiological bases of drought resistance and drought recovery are definitely different, and that maintaining higher chlorophyll content (r = 0.874(***)) and Fv/Fm (r = 0.626(*)) under drought stress contributes to drought recovery. Our results suggest that both drought resistance and recovery are key determinants of plant drought adaptation, and that drought recovery may play a more important role than previously thought. In addition, leaf water potential, chlorophyll content and Fv/Fm could be used as efficient reference indicators in the selection of drought-adaptive genotypes.
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F UniversityYangling, China; College of Life Sciences, Northwest A&F UniversityYangling, China.
authors.forename: Daoqian
authors.initials: D
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F UniversityYangling, China; College of Natural Resources and Environment, Northwest A&F UniversityYangling, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water ResourcesYangling, China.
authors.forename: Shiwen
authors.initials: S
authors.lastname: Wang
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University Yangling, China.
authors.forename: Beibei
authors.initials: B
authors.lastname: Cao
authors.affiliation: Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources Yangling, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Cao
authors.affiliation: Beijing Zhongnong Chuangyou Seed Technology Corporation Limited Beijing, China.
authors.forename: Guohui
authors.initials: G
authors.lastname: Leng
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F UniversityYangling, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water ResourcesYangling, China.
authors.forename: Hongbing
authors.initials: H
authors.lastname: Li
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F UniversityYangling, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water ResourcesYangling, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F UniversityYangling, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water ResourcesYangling, China.
authors.forename: Lun
authors.initials: L
authors.lastname: Shan
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F UniversityYangling, China; College of Life Sciences, Northwest A&F UniversityYangling, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water ResourcesYangling, China.
authors.forename: Xiping
authors.initials: X
authors.lastname: Deng
keywords: drought adaptation; drought recovery; drought resistance; genotypic variation; maize