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Changes in IAA, tryptophan and activity of soluble peroxidase associated with zygotic embryogenesis in Araucaria angustifolia (Brazilian pine)

Astarita, L.V., Floh, E.I.S., Handro, W.
Plant growth regulation 2003 v.39 no.2 pp. 113-118
Araucaria angustifolia, seeds, gametophytes, zygote, embryo (plant), embryogenesis, seed development, cell growth, cell differentiation, developmental stages, chemical constituents of plants, tryptophan, quantitative analysis, peroxidase, enzyme activity, indole acetic acid, Brazil
In A. angustifolia seeds the highest values of free IAA occurred in the embryonic axis, at the initial phases of development. These values decreased sharply coincident with the increase of IAA with the differentiation of cotyledons and seed elongation. During seed development, tryptophan concentrations varied inversely with free IAA and directly with conjugated IAA. An increase in peroxidase activity was followed by a decrease in free IAA in the embryo axis, and in conjugated IAA in the megagametophyte. Megagametophyte tissues did not exhibit significant variation in free IAA during seed development. Following the stage where cotyledons arise, tryptophan decreased in the megagametophyte and increased in the cotyledons and embryonic axis.