Growth regulator requirement for in vitro embryogenic cultures of snowdrop (Galanthus nivalis L.) suitable for germplasm preservation

In this study, we report on the production of bulb scale-derived tissue cultures capable of efficient shoot and plant regeneration in three genotypes of snowdrop (Galanthus nivalis L., Amaryllidaceae), a protected ornamental plant. For culture line A, high auxin and low cytokinin concentration is required for callus production and plant regeneration. The type of auxin is of key importance: α-naphthaleneacetic acid (NAA) in combination with indole-3-acetic acid (IAA) at concentrations of 2 mg L−1 or 2–10 mg L−1 NAA with 1 mg L−1 N6-benzyladenine (BA), a cytokinin on full-strength media are required for regeneration. Cultures showing regeneration were embryogenic. When lines B and C were induced and maintained with 2 mg L−1 NAA and 1 mg L−1 BA, they produced mature bulblets with shoots, without roots. Line A produced immature bulblets with shoots under the above culture condition. Amplified Fragment Length Polymorphism (AFLP) analysis showed that (i) genetic differences between line A and its bulb explants were not significant, therefore these tissue cultures are suitable for germplasm preservation, and (ii) different morphogenetic responses of lines A, B and C originated from genetic differences. Culture line A is suitable for field-growing, cultivation and germplasm preservation of G. nivalis and for the production of Amaryllidaceae alkaloids

Effects of cytokinins on in vitro mineral accumulation and bud development in Annona glabra L. Efeito de citocininas sobre o acúmulo de minerais e desenvolvimento de brotações de Annona glabra L. in vitro

Annona glabra is a tropical species that has significant agronomic potential in terms of furnishing fruits for in natura consumption and for the production of phyto-pharmaceuticals. In vitro cultivation has been considered the most promising form of propagation for this species, although large scale utilization of this technique is currently limited by high rates of leaf abscission, reduced rates of explant multiplication and slow bud growth. The present work evaluated the effects of different cytokinins on mineral accumulation in shoots of A. glabra cultivated in vitro, and their effects on growth and survival of these plants. Buds of A. glabra were cultivated in Wood Plant Medium (WPM) in the presence of 6-benzilaminopurine (BAP), thidiazuron (TDZ), kinetin (KIN), and zeatin (ZEA). KIN and BAP use resulted in the greatest growth, largest accumulation of dry mass and leaf area development, as well as the greatest survival rate during in vitro cultivation of this species. All cytokinins tested stimulated large accumulations of nitrogen and boron in shoots, but diminished levels of calcium as compared to controls.<br>Annona glabra é uma espécie frutífera tropical que apresenta elevado potencial agronômico pelo fornecimento de frutos para o consumo in natura e pela produção de fitofármacos. O cultivo in vitro tem sido preconizado como a forma mais adequada de propagação para essa espécie, embora sua utilização em larga escala ainda seja limitada pela elevada taxa de abscisão foliar, reduzida taxa de multiplicação dos explantes e crescimento lento das brotações. Objetivou-se, neste trabalho, avaliar o efeito de citocininas sobre o acúmulo de minerais nas brotações de A. glabra cultivadas in vitro e seus reflexos sobre o crescimento e sobrevivência das plantas nesse tipo de ambiente. Brotações de A. glabra foram cultivadas em meio Wood Plant Medium (WPM), na presença de 6-benzilaminopurina (BAP), thidiazuron (TDZ), cinetina (KIN) e zeatina (ZEA). A utilização de KIN e BAP induziu maior crescimento, maior acúmulo de massa seca, maior desenvolvimento da área foliar e maior taxa de sobrevivência das plantas durante o cultivo in vitro dessa espécie. Todas as fontes de citocininas testadas estimularam maiores acúmulos de nitrogênio e boro nas brotações e menores de cálcio