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amp1 - a mutant with high cytokinin levels and altered embryonic pattern, faster vegetative growth, constitutive photomorphogenesis and precocious flowering

Authors

  • Abdul M. Chaudhury,

    Corresponding author
    1. CSIRO Division of Plant Industry, G.P.O. Box 1600, Canberra, ACT 2601, Australia
    2. The Co-operative Research Centre for Plant Science, G.P.O. Box 475, Australian National University, Canberra, ACT 2601, Australia
      *For correspondence (fax +61 6 246 5000).
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  • Stuart Letham,

    1. The Co-operative Research Centre for Plant Science, G.P.O. Box 475, Australian National University, Canberra, ACT 2601, Australia
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  • Stuart Craig,

    1. CSIRO Division of Plant Industry, G.P.O. Box 1600, Canberra, ACT 2601, Australia
    2. The Co-operative Research Centre for Plant Science, G.P.O. Box 475, Australian National University, Canberra, ACT 2601, Australia
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  • Elizabeth S. Dennis

    1. CSIRO Division of Plant Industry, G.P.O. Box 1600, Canberra, ACT 2601, Australia
    2. The Co-operative Research Centre for Plant Science, G.P.O. Box 475, Australian National University, Canberra, ACT 2601, Australia
    Search for more papers by this author

*For correspondence (fax +61 6 246 5000).

Abstract

amp1, a mutant of Arabidopsis thaliana has a phenotype altered in three different aspects of plant development; spatial pattern, photomorphogenetic growth, and initiation of flowering. While fewer than 0.1% of the seedlings of wild-type plants are non-dicot as many as 20% of the seedlings of the amp1 mutant are tricot or tetracot. The rate of leaf initiation is faster and vegetative phyllotaxy is altered in amp1. When grown in the dark amp1 seedlings show morphogenetic properties similar to light-grown wild-type plants: they do not form an apical hook, have hypocotyls shorter than wild-type plants and form etiolated true leaves. amp1 mutant flowers significantly earlier than congenic Amp1 plants. The mutant has six times more cytokinin than wild-type suggesting that endogenous cytokinin levels might play an important role in mediating these different developmental processes. AMP1 might code for a negative regulator of cytokinin biosynthesis, or may be required for the degradation of cytokinin.

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