Comparative responses of two Trigonella species to salinity and drought stresses in vitro

Abstract

Effects of salinity and drought on growth, contents of proline, malondialdehyde (MDA), protein<br />and activity of antioxidative enzymes were studied in two Trigonella species. Seeds and<br />explants of T. foenum-graecum and T. aphanoneura were grown on Murashige and Skoog<br />medium (MS) complemented with iso-osmotic concentrations of NaCl (0, 100, 150 mM) and<br />mannitol (0, 180, 275 mM). Growth and relative water content (RWC) of seedlings and calli<br />decreased by increasing of salinity and drought in both species. In contrast to that of calli,<br />proline and protein contents increased in seedlings of both species under both stresses. The<br />increase of proline content in seedlings of T. aphanoneura was higher than that of T. foenumgraecum<br />under NaCl stress. MDA content in seedlings of T. aphanoneura was higher than that<br />of T. foenum-graecum and increased in both species under salinity. Among antioxidative<br />enzymes, catalase (CAT) activity increased continuously in seedlings of T. aphanoneura<br />comparing to that of T. foenum-graecum. Similar increasing trends were obtained regarding<br />CAT activities in calli of both species under both stresses. Increase in activities of SOD, CAT<br />and POX was observed in calli of both species under stress. It seems that undifferentiated calli<br />respond more regularly to both stresses. Finally, higher proline content and lower amount of<br />MDA could be considered as criteria for higher tolerance of T. foenum-graecum seedlings<br />against osmotic stresses.