Myrtaceae anther glands: morphology, anatomy and variation in glandular contents

Context. Most tissues of Myrtaceae plants have oil glands. The anthers of many species have an oil-containing apical gland that is larger than those in other tissues of the plant. Aims. Representative species in the family were examined for the diversity of gland form and their oil contents. Methods. Representative anthers were sectioned for light microscopy and scanning electron microscopy study and anthers from selected species were analysed for oil content. Key results. The most common gland form is globular and narrowly attached to the apex of the connective, but in members of certain tribes, the gland is completely enclosed in the connective. The greatest morphological diversity is in the Chamelaucieae. Anther glands vary from plesiomorphic globular forms to glands that are larger than the anther thecae and almost completely fill the connective. Conclusions. There are three possible functions for the glands, including the following: (1) protecting the anthers from herbivores, (2) mixing with the pollen to aid adhesion to stylar hairs on many Chamelaucineae, and (3) rewarding pollinators that use the oil–pollen mixture as food. Implications. It is generally considered that the oils in various tissues of the Myrtaceae deter herbivores. In Myrtaceae with abundant anthers, the glands could deter flower visitors from consuming the anthers. Gland oil of the Eucalyptus and Leptospermum species examined contained α pinene as did the leaves of all species examined. The gland oil composition in Chamelaucium uncinatum and Verticordia grandis that have pollen presenters was different from that in the leaves and also different from that in the anthers of the two Verticordia species where bees collect the pollen–oil mixture for food.

Details

Title: Myrtaceae anther glands: morphology, anatomy and variation in glandular contents
Authors/Creators: Philip Ladd - Murdoch University, Centre for Terrestrial Ecosystem Science and Sustainability
Publication Details: Australian journal of botany, Vol.72(2), BT23073
Publisher: CSIRO Publishing
Identifiers: 991005649565907891
Murdoch Affiliation: School of Environmental and Conservation Sciences; Centre for Terrestrial Ecosystem Science and Sustainability
Resource Type: Journal article

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