High-frequency shoot regeneration from leaves of the apple rootstock M26 (Malus pumila Mill.)

Abstract

Regeneration of shoots was achieved from in vitro leaves of M26 at frequencies close to 100% on a medium based on MS salts and LS vitamins, containing 4.4#M BA and 0.5~M NAA. Dark and red light gave the best results in inducing shoot regeneration. White light at high intensity helped development of regenerated shoots. Inorganic nitrogen could be reduced by 75% without negative effect, and the presence of NH~ was necessary for regeneration. Leaves were able to regenerate after a 3 kR irradiation (gamma rays), not after 4 kR. Optimal dose should be between 1 and 2 kR.

Influence of nitrogen form and NH4 +-N/:NO3 ?-N ratios on adventitious shoot formation from pear (Pyrus communis) leaf explants in vitro

“…Adventitious shoot regeneration from leaf explants has been reported from several woody fruit species (Chevreau et al 1989;Fasolo et al 1989;James et al 1988;Predieri et al 1989;Tapia y Figueroa & Viseur 1986;Welander 1988). Although the importance of shoot development has been discussed in two recent reviews (Brown & Thorpe 1986;Hutchinson & Zimmerman 1987) most of the work has concentrated on the role of growth regulators on this phenomenon.…”

“…Higher total nitrogen and nitrate reductase have been detected during shoot formation (Brown & Thorpe 1986). For apple, when the ratio of NH4:NO 3 in the regeneration medium was changed from 1:2 to 1:1, the number of regenerated shoots per leaf was decreased, regardless of the total nitrogen level Predieri et al 1989). Chevreau et al (1989) used Quoirin & Lepoivre (1977) salts as a basal medium for adventitious shoot formation on leaves of several pear cultivars.…”

Light Requirement for Shoot Regeneration in Horseradish Hairy Roots

“…Adventitious shoot formation in tobacco calli was reported to be stimulated by blue light and inhibited by red light (15,20). On the other hand, red light stimulated shoot formation in Pseudotsuga menziesii (7), petunia (2), and apple (13). To clarify the underlying mechanisms for light involvement in this process, we are currently attempting to elucidate the involvement of phytochrome in light-induced shoot formation of horseradish.…”

The effect of some macronutrients on adventitious root development on scion apple cultivars in vitro

“…They also showed that the influence of nitrogen in the rooting medium was more important than that of potassium. Fasolo et al [5] and Predieri & Malavasi [17] suggest that the ratio of NHaNO3 to KNO3 influences adventitious shoot formation from apple leaves. In our studies we have found a relationship between the two compounds and root formation.…”