Differential Na2SO4 tolerance in tobacco plants regenerated from Na2SO4‐grown callus

Abstract

Abstract The regenerated shoots from sodium sulphate (Na2SO4) grown callus of tobacco (Nicotiana tabacum L. cv. Wisconsin 38) were evaluated for Na2SO4 tolerance based on shoot proliferation and rooting in vitro, and seed germination in vivo in response to Na2SO4. An increase in Na2SO4 concentration resulted in significantly decreasing shoot fresh weight, number of shoots, shoot length and leaf size, and increasing per cent shoot dry weight of both control and Na2SO4‐grown cultures. In rooting, shoots of Na2SO4‐grown cultures exhibited the highest per cent rooting (85%) in the presence of 1% w/v Na2SO4. However, per cent rooting, root number per rooted cutting and root fresh weight decreased significantly with increasing Na2SO4 concentration when shoots were transferred to the medium in the absence of Na2SO4 for 4‐monthly passages. Following acclimatization of the rooted shoots of Na2SO4‐grown cultures, phenotypic variation was observed during growth and development. There were 13.2% sterile plants. Fertile plants were sorted into normal (N), tolerant (T), and sensitive (S) categories and the respective percentages of plants were 31.6, 44.7 and 10.5, based on per cent germination, germination velocity index and seedling survival to Na2SO4. The response of N, T and S types to Na2SO4 in subsequent shoot proliferation was similar to that of seed germination.