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.

Daoqian Chen,Shiwen Wang,Lina Yin,Lun Shan,Hongbing Li,Guohui Leng,Beibei Cao,Xiping Deng,Dan Cao

doi:10.3389/fpls.2015.01241

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.

Highlights

Drought stress imposes huge reductions in crop yield and is one of the greatest limitations to crop production outside presentday agriculture areas (Chaves et al, 2009)
Non-irrigated crops in temperate climates and irrigated crops under arid climates are subjected to continuous cycles of water stress and re-watering (Perrone et al, 2012)
In order to investigate the physiological basis of genotypic variation in drought adaptation, several droughtrelated physiological parameters were determined

Summary

Introduction

Drought stress imposes huge reductions in crop yield and is one of the greatest limitations to crop production outside presentday agriculture areas (Chaves et al, 2009). Drought resistance is defined by agronomists in terms of “relative yield of genotypes” or “the ability of a crop plant to produce its economic product with minimum loss in a water-deficit environment relative to the water-constraint free management” (Fukai and Cooper, 1995; Fang and Xiong, 2015). As yield is determined by growth and developmental processes, plant growth was considered as a measure of environmental input and adaptive capacity to a particular environment (Blum, 1979; Dolferus, 2014). In crop species like cereals, maintenance of growth under drought is more important than survival (Dolferus, 2014)

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Conclusion