Harakeke under the microscope

Microscopes have played an important role in recent research on harakeke (native New Zealand flax) at the University of Otago. Dr Bronwyn Lowe and other researchers have been working with Māori weavers to investigate a collection of harakeke plants at the Dunedin Botanic Garden (DBG).

The team explored the individual harakeke varieties under the microscope, including their surface waxes and their fibre (muka or whītau) content. They also looked at the weaving properties of the different varieties and have shown that weavers’ experience of the plants correlates well with results from microscopy.

Harakeke’s importance for Māori

Harakeke has great cultural significance for Māori. Traditionally, muka and leaves were used to make a wide variety of woven objects such as kete (baskets), whāriki (mats) and kākahu (clothing). Specific varieties of harakeke were valued for making different objects and were grown for that purpose. However, much of this mātauranga (traditional knowledge) is now fragmented or lost.

There is particularly scant knowledge about Te Waipounamu South Island harakeke varieties (although North Island weaving varieties have now been extensively documented). It’s not clear whether southern Māori favoured harakeke varieties that were distinct from North Island ones and whether they traded harakeke with North Island iwi.

There’s heaps and heaps of knowledge handed down and existing within any weaver, and what was really nice was often there’d be affirmation of the weaving knowledge with the scientific knowledge.

Dr Bronwyn Lowe

A South Island harakeke collection

Over 100 years ago, a collection of 50 varieties of harakeke and wharariki (mountain flax) plants was gifted to the DBG. It now includes 214 individual plants. The collection is regarded as taonga by local iwi (Kāi Tahu). However, the origins and purpose of the collection are unclear. Why was it gifted? Were the harakeke varieties in the collection important to Māori? Could it include South Island-specific varieties?

To answer these questions, researchers at the University of Otago and the Botanic Garden formed partnerships with Māori weavers and others. Together, they set out to explore many characteristics of the harakeke varieties in the collection, including their appearance under the microscope and their weaving properties.

A cross-cultural approach

Because of the cultural significance of harakeke, the research on the DBG collection was done using a kaupapa Māori approach. Kaupapa Māori research aims at positive outcomes for Māori: extensive consultation precedes research, and findings are publicised widely throughout the community. Kaupapa Māori researchers also think carefully about the implications of their research from a Māori perspective. Who does it benefit? How might the findings be used?

The involvement of Māori weavers Kahutoi Te Kanawa, Roka Ngarimu-Cameron, Anna Gorham and Christine Holtham was an important part of the project. The weavers chose which harakeke plants would be studied in detail and assessed the weaving properties of each one. Along with Rua McCallum (who consulted on matāuranga Māori for the project) and others, they were also involved in setting the overall direction of the research and the way it was shared with the community.

Exploring harakeke with microscopes

Dr Bronwyn Lowe used microscopes – particularly the scanning electron microscope (SEM) – to analyse leaves from the harakeke varieties in the collection. SEM is a particularly useful microscope for studying structures like leaves, because it shows the leaf surface (or a cross-section) in three dimensions and at high resolution.

Bronwyn used a particular SEM technique (cryoSEM) in which the leaf is frozen rapidly before being looked at through the microscope and remains frozen throughout the experiment. Freezing the leaf means that it looks as similar as possible to the living leaf, because it bypasses the complex preparation steps that would otherwise be needed to remove all the water from the leaf. (Liquid water would damage the microscope extensively, but frozen water – ice – is OK!)

Bronwyn was especially interested to look at high-resolution images of the waxes on the surface of the harakeke leaves. She found that the waxes formed crystals with interesting shapes that differed among varieties. She also looked at stomata on the leaf surface and found that some varieties had far more than others. Finally, she viewed cross-sections of the leaves to see what the bundles of muka looked like in each variety.

Microscopy and matāuranga Māori

For Bronwyn, one of the most rewarding aspects of the work was seeing how mātauranga Māori and western scientific knowledge could fit together. Often, Bronwyn’s observations on the microscope echoed the weavers’ knowledge of the different harakeke varieties. For example, the varieties that appeared under the microscope to have the biggest, most even muka were also chosen by the weavers as having good muka yields.