Triadimefon ameliorates negative effects of in vitro salt stress on two cultivars of alfalfa(Medicago sativa L.)

Abstract

Triadimefon (TRD) is a member of triazol plant growth regulator group which is responsible for increasing stress tolerance. Effects of TRD on two cultivars of Medicago sativa (Hamedani and Yazdi) were investigated. The in vitro grown plantlets in MS medium were cultured in TRD at concentration 1.0, 2.0 and 4.0 mg/l combined with 0, 100 and 140 mM NaCl respectively. The changes in growth parameters, photosynthetic pigment, carbohydrate, α-tochopherol, glycine betain, proline and proline dehydrogenase (PDH) activity as well as its expression were measured after four weeks post treatment. NaCl treatment decreased overall plant growth and reduced the total chlorophyll, carbohydrate content, PDH activity and increased α-tochopherol, glycine betain content and proline content. The level of PDH transcript was changed in different combinations of NaCl and TRD, however, at 140 mM NaCl and 2 mg/l TRD expression was decreased. When plants were subjected to salt stress, TRD minimized the inhibitory effects of NaCl on plant growth by increasing, total chlorophyll, carbohydrate, α-tochopherol, glycine betaine content.