Rare plants win new friends

Posted on December 6, 2011


New Scanning electron microscope allows expansion of forest data base –

Acacia williamsonii - commonly known as Whirakee Wattle

For most people the Box Ironbark forests of Central Victoria’s gold fields conjure up images of tall trees and tough timber for railway sleepers.

But for La Trobe University scientists Katherine Legge and Sabine Wilkens, it’s the small and delicate things that count in these iconic landscapes; the understory of shrubs, wildflowers – right down to every variety of pollen grain they have been able to document so far.

A recent community environmental award to Bendigo’s Huntly Primary School group was illustrated on Victoria’s Commissioner for Environmental Sustainability Professor Kate Auty’s website by this wonderful image of local Whirrakee Wattle taken from the La Trobe collection.

The school, working with Northern Bendigo Landcare, won the award for its community partnerships which included propagating 300 of the rare Wattles and partnering with Aboriginal people to create a bush-tucker garden.

The image of the Wattle is part of the University’s web-based data bank of plants and pollen assembled by Dr Legge and Dr Wilkens to serve as a research, teaching and community resource.

Unique contribution

La Trobe’s Bendigo campus, says Dr Legge, is fortunate to include a section of preserved Box Ironbark bushland next to the Greater Bendigo National Park. ‘We are therefore in a unique position to contribute to public knowledge about these interesting forests.’

The La Trobe website features more than 40 species of plants from the forest, including, Acacias, Melaleucas, Orchids, Daisies and Lilies, and there are stunning close-up images of their pollen grains, each with its own distinctive shape and intrinsic beauty.

‘The aim of this site is to increase our appreciation of the Box-Ironbark forests not only by providing public access to images of the plants, but also of their interesting and complex pollen grains, which, due to their microscopic size escape the casual visitor or bushwalker,’ says Dr Legge.

With most of Victoria’s Box Ironbark forests missing in action since European settlement, less than 20 per cent of the original cover remains and only a small fraction of that is protected in conservation reserves like the Greater Bendigo National Park. Here they survive, but still far from anywhere near their original condition. 

The forests produce nectar and pollen all year round which is critical for the survival of much native wildlife, including the migratory Swift Parrots, an endangered species.

The total number of plant species for Box-Ironbark forests and woodlands is estimated at more than 1,500, and so far Drs Legge and Wilkens have assembled images of flowers and pollen for a small percentage of these. 

A new scanning electron microscope, due to arrive at the Bendigo campus before the end of the year, will allow the continuing expansion of the image data base.

Highly complex structures

Different types of pollen grains

Dr Legge says the image data base caters for a range of users. Pollens can be identified on the basis of their morphology and are arranged under the plants’ scientific family names, species, and common names.

Pollens have highly complex structures that are characteristic of the plant from which they come, hence the grains can be used help identify plants down to family, genus and sometimes even species.

While gathering and classifying pollen is a scientific objective in itself, the information can be used by other researchers to learn more about pollination agents and the mechanism of pollination.

Identification of plants from pollen is used widely by scientists, as well as industry – for quality control of many foods (for example, honey), forensics, plant taxonomy and paleo-ecological studies.

Possible clues to climate change

Drs Legge and Wilkens collecting plants

Pollen grains are highly resistant to decomposition and, for that reason, can also help us answers questions about these forests going back to ancient times.

They can be extracted from old sediments, possibly revealing something about the composition of Victorian Box-Ironbark forests long before European settlement – as well as changing patterns of distribution, which could be valuable information for studies into the impact of climate change. (ER)