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28 November 2019 | Story Leonie Bolleurs
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Dr Sandy-Lynn Steenhuisen and Ruth Cozien at a spot high up in the Maloti-Drakensberg World Heritage Site, close to Sentinel Peak, photographing a Drakensberg crag lizard underneath the leaves of the ‘Hidden Flower’.

Flowers high up in the Maloti-Drakensberg World Heritage Site made world news when it was discovered that the Drakensberg Crag Lizard is their sole pollinator. 

This first for continental Africa – a plant being pollinated by a lizard – is a discovery by a research group including Dr Sandy-Lynn Steenhuisen, Senior Lecturer in the Department of Plant Sciences and affiliate of the Afromontane Research Unit (ARU) at the Qwaqwa Campus of the University of the Free State (UFS), in collaboration with Dr Timo van der Niet, Prof Steven Johnson, and project leader Ruth Cozien, all from the Pollination Ecology Research Laboratory and Centre for Functional Biodiversity at the University of KwaZulu-Natal.

Besides their work being published in popular news here in South Africa (including an isiZulu article), it has also received coverage in, among others, Belgium, Canada, the Netherlands, and the United States of America. 

Is it a bee, a bird, perhaps a mouse?

‘Hidden Flower’, true to its name, is a plant species with flowers hidden at ground level, underneath the leaves of the plant. Like the leaves, the flowers are also green. With the flowers filled with nectar (up to 1 ml per plant) and strongly scented, one concludes that, just as with other flowers, these flowers must be visited by a pollinator. Is it a bee, is it a bird, perhaps a mouse/non-flying mammal?

According to Dr Steenhuisen, who was brought into the project because of her experience with rodents pollinating proteas, many plants are adapted to attract and be pollinated by a specific animal. They attract their pollinators using particular scents and colours and reward them for their service with, for example, nectar, oil, fragrance, and sometimes even shelter. 

The ‘Hidden Flower’ initially had the group of researchers thinking that it was being pollinated by a non-flying mammal. “Everything about the plant made it look like it should be mammal-pollinated,” Dr Steenhuisen said. 

They investigated all options, using several techniques to assess the contribution of different possible animals to set seed. To further assist them in their quest to find the true pollinator, the team put up motion cameras that recorded activity in the area of the ‘Hidden Flower’. 

Great was their surprise when studying the video material after a week of fieldwork in the mountains, finding shy lizards dipping their snouts in the ‘Hidden Flower’ and lapping up the nectar.

Dr Steenhuisen described this discovery as completely bizarre, exciting, and fascinating. 

To make 100% sure that lizards are pollinating the ‘Hidden Flower’, these animals were excluded from the plants. Results published in a paper in Ecology showed that when the lizards were experimentally excluded from the plants, the number of seeds produced dropped dramatically by almost 95%. This finding helped to further prove their discovery. 

Strong scent and bright orange colour attract

The team researched the new phenomenon and found that although flower visitation by lizards is not unknown, it occurs almost exclusively on oceanic islands. Cozien says one should keep in mind that mountains are like sky islands and might therefore have similarities with oceanic islands in terms of their ecology.

The strong scent and the touch of orange at the base of the inside of the flowers is believed to play an important role in attracting lizards. The little lizard may recognise the spots of orange inside the flowers which resemble the orange colour of a male lizard in mating season, attracting females. Lured by the strong scent and the orange spots, the reptiles stick their snouts into the flower in search of nectar, pollinating the ‘Hidden Flower’; thus, making sure that this flower will continue to grow on the slopes of Sentinel Peak in the Maloti Drakensberg range. 

This research finding on lizard pollination, which reads almost like a fairy tale with its islands, hidden flowers, nectar from the gods, and little dragons, shows that there are still many unknown and surprising interactions that need to be discovered and conserved to ensure a healthy ecological system. 

The research findings of this study were published in April 2019. 

News Archive

Sunflowers are satellite dishes for sunshine, or are they?
2016-07-20

Eighty-six percent of South Africa’s
sunflowers are produced in the
Free State and North West provinces.

Helen Mirren, the English actress, said “the sunflower is like a satellite dish for sunshine”. However, researchers at the University of the Free State (UFS) have found that too much of this sunshine could have a negative effect on the growth of sunflowers, which are a major source of oil in South Africa.

According to Dr Gert Ceronio from the Department of Soil, Crop, and Climate Sciences at the UFS, extremely high soil temperatures play a definite role in the sprouting of sunflower seedlings. Together with Lize Henning, professional officer in the department, and Dr André Nel from the Agricultural Research Council, he is doing research on biotic and abiotic factors that could have an impact on sunflowers.

Description: Sonneblom 2 Tags: Sonneblom 2

Various degrees of deformity (bad-left
to none-right) in seedlings of the same
cultivar at very high soil temperatures.
Photo: Dr Gert Ceronio

Impact of high temperatures on sunflower production

The Free State and North West provinces, which produce 86% of South Africa’s sunflowers, are afflicted especially by high summer temperatures that lead to extremely high soil temperatures.

Dr Ceronio says: “Although sunflower seeds are able to germinate at temperatures from as low as 4°C to as high as 41°C, soil temperatures of 35°C and higher could have a negative effect on the vegetative faculty of sunflower seedlings, and could have an adverse effect on the percentage of sunflowers that germinate. From the end of November until mid-January, this is a common phenomenon in the sandy soil of the Free State and North West provinces. Soil temperatures can easily exceed the critical temperature of 43°C, which can lead to poor germination and even the replanting of sunflowers.”

Since temperature have a huge impact not only on the germination of sunflower seeds, but also on the vegetative faculty and sprouting of sunflower seedlings, Dr Ceronio suggests that sunflowers should be planted in soil with soil temperatures of 22 to 30°C. Planting is usually done in October and early November. Unfortunately, this is not always possible, as soil moisture is not optimal for growth. Farmers are then compelled to plant sunflowers later.

Impact of herbicides on sunflower growth

“High soil temperatures, combined with the herbicide sensitivity of some cultivars, could lead to the poor development of seedlings," says Dr Ceronio.

The use of herbicides, such as ALACHLOR, for the control of weeds in sunflowers is common practice in sunflower production. It has already been determined that ALACHLOR could still have a damaging effect on the seedlings of some cultivars during germination and sprouting, even at recommended application dosages.

“The purpose of the continued research is to establish the sensitivity of sunflower cultivars to ALACHLOR when exposed to high soil temperatures,” says Dr Ceronio.

 

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