Plant regeneration from protoplasts of Capsicum annuum L. cv. California Wonder.

Plant regeneration from mesophyll protoplasts of pepper, Capsicum annuum L. cv. California Wonder has been demonstrated via shoot organogenesis. Protoplasts isolated from fully expanded leaves of 3-week-old axenic shoots when cultured in TM medium supplemented with 1 mg l-1 NAA, 1 mg l-12,4-D, 0 5 mg l-1 BAP (CM 1) resulted in divisions with a frequency ranging from 20-25 %. Antioxidant ascorbic acid and polyvinylpyrrolidone (PVP) in the medium and incubation in the dark helped overcome browning of protoplasts. Microcalli and macrocalli were formed in TM medium containing 2 mg l-1 NAA and 0·5 mg l-1 BAP (CM Π) and MS gelled medium containing 2 mg 1-1 NAA and 0 5 mg 1-1 BAP (CM III), respectively. Regeneration of plantlets was possible via caulogenesis. Microshoots, 2-5 percallus appeared on MS gelled medium enriched with 0·5 mg l-1 IAA, 2mg l-1 GA and l0mg l-1 BAP (CM IVc). Rooting of microshoots was obtained on half strength gelled medium containing 1 mg l-1 NAA and 0·5mg l-1 BAP. Protoplasts isolated from cotyledons failed to divide and degenerated eventually.

Alterations in the activities of the enzymes of proline metabolism in Ragi (Eleusine coracana) leaves during water stress.

Free proline content in Ragi (Eleusine coracana) leaves increased markedly (6 to 85 fold) as the degree of water stress, created by polyethylene gylcol treatment, was prolonged There was also a marginal increase in soluble proteins in the stressed leaves as compared to that in the controls. Water stress stimulated the activities of ornithine aminotransferase and pyrroline-5-carboxylate reductase, the enzymes of proline biosynthesis and markedly inhibited the enzymes involved in proline degradation viz., proline oxidase and pyrroline-5-carboxylate dehydrogenase. These results suggest that increase in free proline content of Ragi leaves could be due to enhanced activities of the enzymes synthesizing proline but more importantly due to severe inhibition of the enzymes degrading proline. These observations establish for the first time, the pathway of proline metabolism in plants by way of detection of the activities of all the enzymes involved and also highlight the role of these enzymes in proline accumulation during water stress.