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

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.

Araucaria angustifolia is a long-lived conifer species with gravity-dispersed seeds (barochory) and wind-dispersed pollen (anemophily).Alternatively, see be dispersed by vertebrates.However, the trans seeds are often damaged by these animals and n to germinate (Müller andMacedo 1980, Mello F al. 1981).The pollination occurs between Sep and October, and seed ripening occurs from M July.The reproductive cycle of A. angustifolia in general, around two years from the beginning female cone development until seed dispersion and Hattemer 2003, Mantovani et al. 2004).
Aracaria angustifolia is a mainly dioeciou cies, but monoiceous specimens are seldom found ture.The occurrence of monoicy in A. angustifo been suggested to occur as an effect of pathoge fections or other sort of injuries in the adult plant and Klein 1966).Up to now, no other physiolog functional explanation has been proposed for the "main" -2009/9/30 -13:26 -page 702 -#2

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VALDIR M. STEFENON and CLARISSA A. CAPRESTANO angustifolia found in its natural area of occurrence, in Santa Catarina State, Brazil.The general structure of pollen grains was also studied and compared to the one of pollen grains of dioecious specimens of A. angustifolia described in the literature.

MATERIALS AND METHODS
The studied plant material was collected in the municipality of Lages, state of Santa Catarina, southern Brazil ( 27• 49 59 S and 50 • 20 49 W).The collection occurred at October, 9 th 2008.The tree is around 40 years old and is cultivated in a domestic backyard.A branch with male and female cones (Fig. 1) was collected and the voucher specimen was housed at the Herbarium Flor of the Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil, under the register number Flor-37053.Pictures were captured in the Laboratory of Developmental Plant Physiology and Plant Genetics of the Federal University of Santa Catarina using a stereomicroscope Olympus SZH10 or a digital camera Panasonic LZ3.For Scanning Electron Microscopy (SEM), naturally dehydrated pollen grains were coated with gold-palladium and analyzed using a Jeol JSM-6390LV microscope at the Central Laboratory of Electronic Microscopy of the Federal University of Santa Catarina.

RESULTS AND DISCUSSION
The occurrence of monoicy in A. angustifolia was firstly documented by Reitz and Klein (1966) and to our knowledge no further reports on this topic were published.Monoicy can be expressed in A. angustifolia in three different forms: (i) trees that produced exclusively female (or male) cones during a certain period of time and then started to produce just male (or female) 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).The holotypus described by these authors (collected in September 1962) represented the latter class of monoicy.The other two categories of monoicy were just reported as personal communications

GENERAL MORPHOLOGY
In contrast to the hypothesis of pathogenic infections or physical damages as grounds for the monoicy in Araucaria angustifolia, the specimen described here presented healthy appearance, suggesting other physiological cause for this event.The tree produced both male and female cones in the same branch (Fig. 1).As a rule, male and female cones were observed in the same branch, but not in the same ramifications of the branch.Evidences of active production of reproductive structures are given by the presence of immature male and female cones (Figs. 2 and 3), in addition to the mature male cones and the developing female cones observed.

MALE STRUCTURES AND POLLEN MORPHOLOGY
The mature male cones (Figs. 1 and 2) presented a typical form: they were cylindrical, brown-colored, slightly curved and large, reaching about 15 cm long.The microsporophylls were densely and spirally disposed in the axis of the cone.The monoiceous specimen of A. angustifolia infected with the fungus Uleiella paradoxa Schroet.(Uredinales) described by Reitz and Klein (1966) presented wounded pollen grains and abnormally ramified male cones.The fungus infection was considered by the authors as the cause of the monoicy of the tree.Like the cones, microsporophylls of the specimen described here presented normal morphology, comprising eight microsporangia (Figs. 7 and 8) and producing a huge amount of pollen.Pollen grains are large in comparison to other conifer species (the average from 50 observations was around 50μm; Figs. 9 and 10), sphereshaped and lack structures to assist the fly, as described by Sousa and Hattemer (2003).The pollen grains have a granulated surface formed by irregularly dispersed granules of the exine (Fig. 11).Equivalent characteristics were described by Del Fueyo et al. (2008) for pollen grains of dioecious specimens of A. angustifolia.

FEMALE STRUCTURES AND POLLINATION
The older female cone studied produced seeds (Fig. 4), between March and June.Also younger female cones analyzed were already pollinated (Figs. 5 and 6).The monoiceous specimen studied dispersed its pollen from August to September 2008.As a result of the large area of distribution, it is expected that the reproductive phenology of A. angustifolia differs among regions of occurrence.In Brazil, pollination of A. angustifolia has been reported to occur from August to mid-November (Sousa and Hattemer 2003, Mantovani et al. 2004, Anselmini et al. 2006).
Considering the position of the male cones above the female ones (Fig. 2), the occurrence of self-pollination is a liable event.Pollen grains of A. angustifolia lack a device to enhance its fly and have a relatively low floating rate (from 12.02 to 19.89 cm.s -1 ) when compared with other tree species (Sousa and Hattemer 2003).These features limiting distance of pollen dispersion increase the probability of auto-pollination in this monoiceous specimen.
have to be tested in order to highlight possible physiological aspects related with the monoicy of this specimen.An ongoing study will characterize the reproductive phenology of this tree, as well as potential physiological features linked to its monoicy.Additionally, tests for auto-pollination using molecular markers will be performed after seeds' fertilization and will be reported in an upcoming paper.

Fig. 1 -
Fig. 1 -Branch showing male and female cones.Note the normal morphological appearance of the reproductive structures.Scale bar = 10 cm.Fig. 2 -Mature male cones and immature female ones, which will maturate in about 18 months.Fig. 3 -Young male cone.Scale bar = 1 cm.Fig. 4 -Seeds of the older female cone present in the collected branch.Scale bar = 1 cm.