A botanical adventure in Africa

Some aloe plants are used as medicine for people and animals. Other aloes are lethal and used as poison. PHOTO: EVA BRÆNDYou have probably heard of a house plant called aloe vera. All over the world, the sap from the plant's thick leaves is used to heal skin wounds.

The aloe vera plant is part of the large aloe family. Some 500 species of aloe grow wild in Africa. They grow all across southern and eastern Africa, from the high mountains right down to the shoreline. Aloe plants differ considerably in appearance. Some are small like blades of grass. Others are 20 metres high. Yet all of them have thick, leathery leaves containing a bitter sap. Some of the plants are used as medicine for people and animals. Many aloes are lethal, and are used for poison darts and poison bait. Take for example, the tragedy that occurred in the year 983 when Germany's Emperor Otto II died from taking 16 grams of aloe for constipation.

Norwegian Charlotte is the first person in the world to explore the relationship between aloe plants in Africa. PHOTO: EVA BRÆNDNorwegian pioneer

The Norwegian student Charlotte Sletten Bjorå from the University of Oslo is the first person in the world to examine the genetic relationship between the different species of aloe plants in Africa.

Up to today, botanists always categorised aloes on the basis of their appearance. Botanists call this way of classifying plants morphology. The big aloe trees are placed in one group, the small aloes in another, and aloe bushes in a third group.

Climbing on her quest for Aloe flexilifolia, whose provenance is limited to a tiny area of Tanzania. PHOTO: EVA BRÆNDDefying danger

However, gene tests indicate that this classification is wrong. Now Charlotte is bringing order to chaos. Over the past few years, she has travelled across large parts of the bush in Africa and collected about 400 species of aloe, but her field work is difficult. Many of the plants thrive best on rocky outcroppings and steep cliffs. Once she encountered a swarm of angry wasps as she was scaling a dizzying 80-metre high ravine. Another time she stopped short just a few metres before stumbling across a black mamba, one of the most poisonous snakes in the world. She has also saved a colleague from drowning in quicksand. Occasionally, she has also had to be escorted by armed guards to protect her from dangerous animals and assailants.

Aloe mawii from Mount Mulanje in Malawi. PHOTO: EVA BRÆNDWet and sticky

Charlotte maintains it is best to collect the plants when they are in bloom. To preserve the plants, she presses them on herbarium sheets. But aloes are not easy to press because their leaves are full of sap. That often makes the process quite sticky and the work difficult, since wet plants decompose. As a result, she spends most evenings drying herbarium sheets and her flower press by the campfire.

Once back home in Oslo, she undertakes genetic analyses of the aloe plants. She does that by crushing the cells in the leaf and extracting DNA molecules. Then she compares the DNA patterns of the aloe plants. The more similar the patterns, the closer the family relationship.

Charlotte Bjorå has a greenhouse full of aloe plants at the Botanical Museum in Oslo. PHOTO: EVA BRÆNDGreenhouse to the rescue

Fortunately, Charlotte has a greenhouse for aloes at the Botanical Museum in Oslo. That has been a great advantage since it is not always easy to get home to Norway in time while the aloes are in blossom. With the greenhouse, she can bring seeds home and wait for the aloes to blossom in the greenhouse.

Sometimes the same species of aloe looks very different, depending on whether the plants grow in the mountains or on the lowlands. They may even have been described as two different species previously. Working in the greenhouse allows her to study whether they are identical when grown under the same temperature and light conditions.

She contends that her research is important, not least because many aloes are threatened by extinction. We need to know more about the rare aloes to protect and preserve them.

Translation: Linda Sivesind

*Published in 'Nysgjerrigper' no. 3/06*