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Gradients of adventitious bud formation on excised epicotyl and root sections of citrus

1986; Elsevier BV; Volume: 43; Issue: 3 Linguagem: Inglês

10.1016/0168-9452(86)90023-3

1873-2259

David W. Burger, Wesley P. Hackett,

Plant Molecular Biology Research

Epicotyl and root sections from 'Valencia' orange (Citrus sinensis (L.) Osb.) seedlings were cultured in vitro on a Murashige-Tucker medium containing benzylaminopurine (BAP) and varying naphthaleneacetic acid (NAA) concentrations. A gradient of bud-forming potential was observed in both epicotyls and roots. NAA influenced the expression of the gradient with a concentration of 0.02 mg/l enhancing the expression and a concentration of 2 mg/l diminishing it. The presence or absence of the shoot and/or root apices did not influence the bud-forming capacity of cultured sections of epicotyls or roots. However, the presence of cotyledons did increase the bud-forming capacity of epicotyl sections 1 cm from the cotyledonary node. These data support the hypothesis that the bud-forming gradient in 'Valencia' epicotyls may be due to the presence of promoting substance(s) emanating from the cotyledons. However, the data do not support this hypothesis for explaining the bud-forming gradient in roots.