ISSN 1021-4437, Russian Journal of Plant Physiology, 2010, Vol. 57, No. 6, pp. 784–791. © Pleiades Publishing, Ltd., 2010. 784 1 INTRODUCTION The halophytic plant, Aeluropus lagopoides from Poaceae family is a stoloniferous perennial grass that has a C 4 type of photosynthesis. It is distributed in the regions with intermediate salinity and semi-desert cli- mate on Iranian plateau and is one of the animal for- age plants [1]. Vegetative propagation is one of the advantages of A. lagopoides to produce identical plant lines, which are needed for investigation of molecular and physiological aspects of adaptation to harsh envi- ronmental conditions. The patterns of ion secretion by A. lagopoides as a powerful strategy to cope with salt stress were reported [2]. A. lagopoides is very important plant because it can tolerate high salt and drought stress levels; it belongs to Poaceae, which is an impor- tant family of crops, including wheat and rice. Colmer 1 This text was submitted by the authors in English. et al. [3] have reported that it is possible to use wild rel- atives to improve wheat salt tolerance. Wei et al. [4] have reported the transfer of salt tolerance to wheat from A. littoralis, which is its wild and remote relative. To investigate the salt tolerance transfer to hybrid clones, proline content and the Na + /K + ratio were analyzed, and these two parameters were increased in hybrid clones under salt stress [4]. NaCl inhibits plant growth by osmotic or water- deficit effect and salt-specific or ion-excess effect [5]. Several roles for proline in plants are osmotic adjust- ment, stabilizing subcellular structures, scavenging free radicals, and buffering the cell redox potential under stress conditions [6]. Proline can also induce expression of salt stress-responsive genes, which have proline-responsive elements in their promoters [7]. Earlier, it has been shown that proline content in A. lagopoides was dramatically increased under drought stress [8]. The effect of salt stress on plant growth depends on the plant species. In Salicornia rubra, fresh and dry RESEARCH PAPERS Salt Stress Responses of a Halophytic Grass Aeluropus lagopoides and Subsequent Recovery 1 Hamid Sobhanian a, b, c, d , Nasrin Motamed a , Ferdous Rastgar Jazii b , Khadija Razavi b , Vahid Niknam a , and Setsuko Komatsu c a School of Biology, College of Science, University of Tehran, Tehran 14155-6455, Iran; fax: +98-21-6640-5141; e-mail: motamed2@khayam.ut.ac.ir b National Research Center for Genetic Engineering and Biotechnology, Tehran 14155-6343, Iran c National Institute of Crop Science, Tsukuba 305-8518, Japan d Payame Noor University, Tehran 19395-4697, Iran Received February 25, 2009 Abstract—To investigate the salt tolerance mechanisms, Aeluropus lagopoides as a halophytic plant was used. Plants were treated with 0, 150, 450, 600, and 750 mM NaCl and harvested at 0, 4, 8, and 10 days after treat- ment and 1 day and 1 week after recovery. Optimal growth, measured as fresh and dry weights, occurred at 150 mM NaCl, but it was suppressed by 450, 600, and 750 mM NaCl. Recovery significantly increased fresh and dry weights only in 750 mM NaCl-treated plants. Water content was decreased after NaCl treatment and increased after recovery. Na + and proline contents and activity of superoxide dismutase (SOD) were increased after NaCl treatment and decreased after recovery in all treated plants. In contrast, K + content and ascorbate peroxidase activity decreased after NaCl treatment and increased after recovery in all treated plants. Catalase (CAT) was activated only in 750 mM NaCl-treated plants. Total content of soluble protein was slightly changed after NaCl treatment. It was concluded that proline accumulation for osmotic adjustment, SOD activation for scavenging, and CAT activation at the higher level of salt stress to detoxify produced H 2 O 2 were main A. lagopoides strategies under salt stress. A. lagopoides salt tolerance was not based on the restriction of Na + uptake. Keywords: Aeluropus lagopoides, antioxidant enzymes, growth, halophyte, ion content, proline, recovery, salt stress. DOI: 10.1134/S1021443710060063 O 2 •– Abbreviations: APX—ascorbate peroxidase; CAT—catalase; SOD—superoxide dismutase.