IN-VITRO SELECTION AND CHARACTERIZATION OF TRANS-4-HYDROXY-L-PROLINE RESISTANT CALLUS LINES OF VIGNA-RADIATA - TOLERANCE TO NACL

A hydroxyproline resistant (Hyp(r)) callus line of Vigna radiata (L.) Wilczek has been isolated as a spontaneous variant, on agar solidified PC-L2 medium supplemented with 10 mM hydroxyproline (Hyp), a concentr ation lethal to wild type cells. The selected clone contained higher e ndogenous level of free proline and K+. The stability of selected trai t was determined by growing it on normal medium for 3 months and then bringing back it on the Hyp-containing medium. This cell-line grew wel l on medium containing 10 mM Hyp and still contained more proline and K+ than the wild type. Hyp(r) callus line showed better tolerance to e xogenously supplied NaCl in the medium than the normal sensitive callu s line. On salt medium, Hypr callus line synthesized more proline and maintained more K+ than the wild type. Higher endogenous levels of pro line and K+ appear to impart dual resistance to Hyp and NaCl to the se lected cell line.