Characterization of alfalfa (Medicago sativa L.) following in vitro selection for salt tolerance

Abstract

Alfalfa (Medicago sativa L .) is a valuable forage crop which is grown in areas of limited rainfall, high temperature and where the land is often salt affected . Seedlings of the commercial variety CUF 101 and the more salt tolerant breeding line CUF101-1S were used as explant material to produce tissue cultures for an in vitro screen for salt tolerance. Callus cultures were placed on a regeneration medium containing 0-350 mol m-3 NaCl to establish the highest possible salt concentration that would allow buds to regenerate and survive as plantlets . Buds were regenerated in 250 mol m-3 NaCl then isolated, grown to maturity and set seed . The response to salt tolerance in the short term was investigated by exposing 14-day-old seedlings to 200 mol m-3 NaCl . Measurement of growth, survival, proline concentration and the activity of antioxidant enzymes were made after 14 days exposure to NaCl .

Physiological Characterization of Six Wheat Genotypes for Drought Tolerance

“…Plant accumulates higher concentration of free proline in their leaves and other tissues while exposed to abiotic stress conditions (Tan & Hollaran, 1982). Similar finding were also reported by other scientists (Sharpe and Verslues, 1999;Safarnejad et al, 1996;Staden et al, 1999;Mattioni, 1997;Serraj & Sinclair, 2002). Prominent accumulation of proline might be act as a protective mechanism to maintaining protein structures and ROS at equilibrium level.…”

Achievements and Challenges in Improving Temperate Perennial Forage Legumes

“…Direct selection at low and moderate levels of salinity has been shown to be effective (Johnson et al, 1992b;Al-Khatib et al, 1993). Assays have been developed including a greenhouse protocol (Peel et al, 2004) and in vitro selection (Winicov, 1991;Safarnejad et al, 1996). Selection at multiple growth stages has been shown to be important (Johnson et al, 1992a).…”

“…However, in vitro mass selection performed on seedlings may provide a cost-efficient means for selecting for tolerance to specific stresses. An in vitro protocol has recently been established to screen alfalfa for aluminium tolerance , and other protocols may be successful for other target traits, e.g., salt tolerance (Safarnejad et al, 1996) …”

Genetic diversity andin vitroassessment of salt tolerance responses and associated changes in gene expression of male poplar (Populus) trees

“…The inland salinity area is one of the major problems, which is continuously expanding, due to natural underground salt, unsustainable agricultural cultivation, low-quality irrigation, industrial waste and human-induced salinization (Pitman & Läuchli, 2002). Limited plant growth and reduced yield caused by these stresses are responsible for enormous economic losses worldwide (Safarnejad, 2004); therefore, the lack of salt-tolerant species is an important barrier to solving this problem.…”