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All aerial tissues and organs of higher plants aregenerated from the shoot apical meristem (SAM) containinga pluripotent stem cell population. The maintenance of shootmeristem activity, such as cell proliferation and differentiation,is important for appropriate normal growth as well asadaptive plastic development under abiotic stress conditions. Here we report that the effects of salt tolerance on Arabidopsisshoot growth may occur via shoot meristem activity. Interestingly, the clv3-2 and clv1 bam1 mutants showed thesalt tolerant phenotype on shoot growth and developmentthrough the increased number of actively dividing cells inthe SAM but not the promoted expression levels of thetypical stress-responsive genes. The reduction of 5-ethynyl-2'-deoxyuridine (EdU)-labeled dividing cells in the SAM bythe treatment of abiotic stresses occurred most likelythrough abscisic acid (ABA) and reactive oxygen species(ROS). In addition, shoot meristem activity via cell proliferationwas regulated dynamically depending on the presence orabsence of abiotic stimuli. Therefore, these results suggestthat stem cell maintenance and differentiation in the SAM mayplay an important role in stress tolerance for developmentalplasticity on plant growth against unfavorable environmentalconditions.