Wheatley, Andrew O.; Ahmad, Mohammed H.; Asemota, Helen N.; Osuji, G.
Author Affiliation, Ana.
Department of Basic Medical Sciences
Development of salt tolerance in in vitro yam (Dioscorea) plantlets
Jamaican journal of science and technology
Date of Publication
The development of plants capable of growing under saline conditions is one approach at utilizing saline soils that are otherwise arable. The study was designed to develop salt tolerant yam (Dioscorea alata) plantlets, using tissue culture techniques. Salt tolerant yam (Dioscorea alata cv. Sweet yam) plantlets were produced in vitro through repeated culturing and selection on saline media. Two hundred plantlets were subcultured on normal multiplication media (MS basal media with 30g/L sucrose and 0.1 mg/L benzylaminopurine). A further 400plantlets was equally subcultured on multiplication media supplemented with 100mM and 200mM NaCl. Plantlets that thrived under saline conditions were repeatedly subcultured on saline media. Growth of plantlets and root formation were assessed along with the biochemical parameters, invertase (EC 126.96.36.199), peroxidase (EC 188.8.131.52), and polyphenol oxidase (EC 184.108.40.206). No growth was observed for plantlets transferred to the highly saline media of 200 mM NaCl and the explants did not survive beyond six weeks. Control plantlets exhibited 100% rooting within three weeks compared to five weeka for plantlets on 100 mM NaCl. Development of new nodes and leaves were observed for plantlets on 100 mM NaCl, although at an initially slower rate for those in saline media than control. The enzyme profiles obtained for plantlets on 100 mM NaCl revealed the biochemical adjustments of the plantlets to cope with the saline conditions. This was further substantiated by the detection of two reproducible bands corresponding to approximately 1kb and 0.35kb from RT-PCR studies of salt tolerant yam plantlets. These result can be translated into efforts aimed at maximizing the use of saline soils.....