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Salinity and waterlogging are two major factors affecting crop production around the world and often occur together (e.g., salt brought to the surface by rising water tables). While the physiological and molecular mechanisms of plant responses to each of these environmental constraints are studied in detail, the mechanisms underlying plant tolerance to their combined stress are much less understood. In this study, whole-plant physiological responses to individual/combined salinity and waterlogging stresses were studied using two barley varieties grown in either vermiculite (semi-hydroponics) or sandy loam. Two weeks of combined salinity and waterlogging treatment significantly decreased plant biomass, chlorophyll content, maximal quantum efficiency of PSII and water content (WC) in both varieties, while the percentage of chlorotic and necrotic leaves and leaf sap osmolality increased. The adverse effects of the combined stresses were much stronger in the waterlogging-sensitive variety Naso Nijo. Compared with salinity stress alone, the combined stress resulted in a 2-fold increase in leaf Na⁺, but a 40% decrease in leaf K⁺ content. Importantly, the effects of the combined stress were more pronounced in sandy loam compared with vermiculite and correlated with changes in the soil redox potential and accumulation of Mn and Fe in the waterlogged soils. It is concluded that hypoxia alone is not a major factor determining differential plant growth under adverse stress conditions, and that elemental toxicities resulting from changes in soil redox potential have a major impact on genotypic differences in plant physiological and agronomical responses. These results are further discussed in the context of plant breeding for waterlogging stress tolerance.

Item Type:	Refereed Article
Keywords:	salinity, waterlogging, microelement toxicity, barley, breeding, manganese, potassium, sodium
Research Division:	Agricultural, Veterinary and Food Sciences
Research Group:	Crop and pasture production
Research Field:	Crop and pasture improvement (incl. selection and breeding)
Objective Division:	Plant Production and Plant Primary Products
Objective Group:	Grains and seeds
Objective Field:	Barley
UTAS Author:	Zeng, F (Dr Fanrong Zeng)
UTAS Author:	Shabala, L (Associate Professor Lana Shabala)
UTAS Author:	Zhou, M (Professor Meixue Zhou)
UTAS Author:	Shabala, S (Professor Sergey Shabala)
ID Code:	87403
Year Published:	2013
Funding Support:	Australian Research Council (LP120200516)
Web of Science® Times Cited:	68
Deposited By:	Tasmanian Institute of Agriculture
Deposited On:	2013-11-14
Last Modified:	2014-07-30
Downloads:	317 View Download Statistics