Callus Induction and Plant Regeneration in Alstroemeria

Callus was induced from mature embryos of Alstroemeria cv. ‘Butterfly’cultured on MS medium supplemented with 2·0 or 4·0mg dm^–3 2,4–D or picloram and incubated at 25°Cin the dark. The effect of auxin concentration and precultureof embryos was studied. Callus was capable of regeneration aftertransfer to MS medium containing 4.0 mg dm°3 BAP. Shootsand whole plantlets were regenerated. The effect of growth regulators,used in the callus induction medium and the regeneration medium,on plant regeneration was studied Key words: Alstroemeria, callus, plant regeneration.     

Induction of Mutation by γ-Irradiation in the Presence of Oxygen or Nitrogen

The effect of γ-irradiation on Aspergillus nidulans genes depends on the presence of oxygen.     

In vitro root induction in axillary microshoots of Quercus robur L.

Whilst considerable efforts have been made to optimise shoot multiplication and rooting in oak, little attention has been paid to the impact of conditions used for multiplication on subsequent root formation. An optimised technique for rooting of oak microshoots has been developed to assess the effect of cytokinin treatments applied to shoot multiplication cultures on the subsequent rooting of microshoots. We found IBA to be more effective at inducing root formation in microshoots than NAA. Efficient rooting of oak microshoots (80%) was achieved after 35 days on medium supplemented with 1.0 mg litre^-1 IBA. Lower concentrations of IBA reduced the frequency of root formation and significantly increased the time taken for microshoots to form roots. High concentrations of IBA (3.0 mg litre^-1) produced similar rooting frequencies but with significantly increased numbers of roots formed by each microshoot. However, high concentrations of IBA stimulated the production of basal callus. Rooting of microshoots was unaffected by the concentration of BA used during shoot multiplication, although basal callusing was greater in microshoots taken from multiplication medium supplemented with the highest concentration of BA (1.0 mg litre^-1) and rooted on medium supplemented with 3.0 mg litre IBA. Reducing the period of exposure to auxin to 7 days by transferring microshoots to auxin-free medium increased the frequency of root formation (84%), led to more rapid root formation and a reduction in basal callus formation.     

An Anatomical Study of Rhizome Bud Formation Induced by Paclobutrazol and Adventitious Root Formation in In Vitro Cultures of Lapageria rosea (Ruiz et Pav.)

An anatomical study was made of bud dimorphism in in vitro shootcultures of Lapageria rosea cv. Nashcourt, utilizing the presenceand absence of the gibberellin-biosynthesis inhibitor paclobutrazol(10 µM) in the medium to control the development of axillarybuds. Patterns of axillary bud development differed betweenthe aerial pattern of shoot extension (in the absence of paclobutrazol)and rhizome bud formation (in the presence of paclobutrazol),with respect to planes of cell division, cell expansion andthe formation of adventitious root primordia. These differencesare examined and discussed. Lapageria rosea cv. Nashcourt, Chilean Bellflower, rhizome bud, paclobutrazol, gibberellin biosynthesis inhibitor, micropropagation