Regeneration of the tropical legume Aeschynomene sensitiva Sw. from root explants

Abstract

Regeneration of Aeschynomene sensitiva Sw. after caUogenesis was obtained from small (2-5 mm long) root explants of 30-day-old seedlings aseptically cultivated on Murashige and Skoog medium supplemented with various concentrations of growth regulators. After 4 weeks, the best results were observed with 0.54 ~ c~-naphthaleneacetic acid and 2.22 BM benzyladenine. On this medium, the rate of regeneration depended on seedling age and agar concentration. The highest number of shoots per explant was obtained with small cuttings from 30-day-old seedlings grown on a medium containing 8 g 1 -i of agar. Regeneration success was also dependent on explant size. When longer explants (7-20 mm) were cut from the main root, direct regeneration was obtained in two weeks. These cuttings also generated shoots through callogenesis in four weeks but always in lower quantities than with direct regeneration, whatever the seedling age. Here also, the best regeneration was obtained with cuttings from 30-day-old seedlings maintained on a medium with 8 g 1-1 of agar. Regenerants were rooted on growth-regulator-free Murashige and Skoog medium and then acclimatized in a greenhouse. A better survival to transplantation was observed when plantlets were inoculated with the photosynthetic Bradyrhizobium strain ORS 278. Stem and root nodules developed on the inoculated plantlets and were able to fix nitrogen.

In vitro regeneration of peanut (Arachis hypogaea L.) through organogenesis: Effect of culture temperature and silver nitrate

“…The highest shoot proliferation rates were obtained when calluses were subcultured to fresh regeneration medium containing 5 p,M AgNOs 4 wk after culture initiation (Table 2). Silver nitrate is an inhibitor of ethylene action reported to improve morphogenetic efficiency in several species (Chraibi et al, 1991;Mukhopadhyay et al, 1992;Nef-Campa et al, 1996) and ethylene production is reported to increase in response to stress, including in tissue culture (Mukhopadhyay et al, 1992). The stress caused by the removal of the first shoots could conceivably stimulate ethylene production, with the consequent inhibition of further morphogenesis.…”

An Efficient <i>In Vitro</i> Propagation System for Purple Cone-Flower (<i>Echinacea Purpurea</i> L.)

“…Age of plantlets greatly influenced the regeneration ability of explants excised from garlic root tips, which reached the maximum value (95%) in 15 days old plantlets (Muhammad et al 1997). In addition the highest number of shoots per explant was obtained from 30 days old seedlings in Aeschynomene sensitiva (Claudine et al 1996). Up to the date the effect of planting material with plantlets age on shoot regeneration has not been reported in E. purpurea.…”

Plant regeneration in Arachis stenosperma Krapov. and W. C. Gregory from roots and calluses derived from leaflets of in vitro plants

“…Bud formation from roots is a natural phenomenon observed in some plants, especially under stress conditions. In vitro shoot production from roots can occur spontaneously after long culture periods or be induced by growth regulators, even in those species that do not have this natural ability (Nef-Campa et al 1996;Hosseini-Nasr and Rashid 2002). In Arachis, shoot differentiation from root tissues has already been observed in field conditions (Krapovickas and Gregory 1994) and it was also described in old in vitro cultures of A. villosulicarpa, in response to combinations of NAA and BA (Pittman et al 1984).…”