A study of salt tolerance in Arabidopsis thaliana and Hordeum vulgare

QK Botany

Attumi, Alarbe ; Dominy, Peter

University:University of Glasgow

Department:Institute of Molecular Cell and Systems Biology

关键词: Salt tolerance, Arabidopsis thaliana, Hordeum vulgare.;   

Others  :  http://theses.gla.ac.uk/114/1/2007attumiphd.pdf

来源: University of Glasgow

【 摘 要 】

ABSTRACTThe original objective of this work was to compare the cellular processes in salt tolerantand salt sensitive plants cells to gain insight into the mechanisms that conferhalotolerance. Halotolerant and salt sensitive cell lines were derived from the modelglycophyte Arabidopsis thaliana; in addition cell suspension cultures from the dicothalophytes Beta vulgaris and Atriplex halimus were also generated. Unfortunately,severe disruptions were encountered following a serious fire; persistent power failures,and failures of new equipment hampered progress with this work. For this reason, onlycomparisons between the Arabidopsis cell lines were completed. The halotolerant(HHS) cell lines survival strategy is to prevent Na accumulation when grown in < 100mM NaCl. Wild type (WT) cells grow faster than HHS cells in the absence of NaCl, butrapidly take up Na in 50 mM NaCl where their growth is severely affected, and fail togrow completely above 100 mM NaCl. No evidence was found to suggest this growthimpairment arose from osmotic stress or nutrient ion deficiencies. Protein profiling ofHHS cells identified a number of proteins whose abundance is regulated by salt stress.These included proteins involved in ion transport, central metabolism, and general stressresponses. The implications of these findings are discussed.In a separate project, a whole plant approach was taken to establish the physiologicalmechanisms that account for the reported difference in halotolerance between twocommercially grown barley lines originating from China. Measurements on growth anddevelopment, plant water status, tissue ion profiling, photosynthesis rates, andtranspiration rates suggested the tolerant line (Zhou 1) enters the reproductive phase ofits life cycle approximately one week earlier than the sensitive line (Zhou 85), and thiscritical period allows floral development resulting in improved yields. This earlyiiflowering is not associated with the well characterized PpD-H1 locus controlling earlyflowering in cereals.The main conclusion from this study is that for glycophytes that do not complete a fulllife cycle above 100 mM NaCl (which includes all of the world’s major crops), it is theionic component of salinity stress that impairs growth and yield. Further research onsalinity stress in crops should focus on understanding the processes that control ionicbalance rather than osmoregulation.