Monoicy in A. angustifolia (Bert.) O. Kuntze (Araucariaceae): I. Morphological aspects of the reproductive structures

Valdir M Stefenon,Clarissa A Caprestano

doi:10.1590/s0001-37652009000400009

Valdir M Stefenon, Clarissa A Caprestano

Open Access

https://doi.org/10.1590/s0001-37652009000400009

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Abstract

Araucaria angustifolia (Bert.) O. Kuntze is a dioecious conifer species native of Brazil. The rare occurrence of monoiceous specimens have been attributed to pathogenic infections or other injuries in adult trees. Here, the morphological characteristics of male and female cones and pollen grains of a monoiceous A. angustifolia are described. Male and female cones and pollen grains presented normal morphology, lacking any sort of injuries or infection and suggesting the existence of further grounds for the occurrence of monoicy in this conifer species.

Highlights

The genus Araucaria de Jussieu (Araucariaceae) includes 19 species with current geographic distribution restricted to the Southern hemisphere (Golte 1993)
The occurrence of monoicy in A. angustifolia has been suggested to occur as an effect of pathogenic infections or other sort of injuries in the adult plant (Reitz and Klein 1966)
Monoicy can be expressed in A. angustifolia in three different forms: (i) trees that produced exclusively female cones during a certain period of time and started to produce just male ones; (ii) trees that produce just female cones some years and both male and female cones in the others; and (iii) trees producing both kinds of cones, simultaneously in the same tree (Reitz and Klein 1966)

Summary

Introduction

The genus Araucaria de Jussieu (Araucariaceae) includes 19 species with current geographic distribution restricted to the Southern hemisphere (Golte 1993). Based on ripening time and seed color, ten botanical varieties of A. angustifolia are described: 1) elegans; 2) sancti josephi; 3) angustifolia; 4) caiova; 5) indehiscens; 6) nigra; 7) striata; 8) semi-alba; 9) alba (Reitz and Klein 1966) and 10) catarinensis (Matos 1994). Araucaria angustifolia is a long-lived conifer species with gravity-dispersed seeds (barochory) and wind-. Aracaria angustifolia is a mainly dioecious species, but monoiceous specimens are seldom found in nature. The occurrence of monoicy in A. angustifolia has been suggested to occur as an effect of pathogenic infections or other sort of injuries in the adult plant (Reitz and Klein 1966). The present note describes the morphological characterization of male and female reproductive structures of a monoiceous specimen of A

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