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14 August 2018
WomenofKovsies Dr Lize Joubert on flowers and their favourite insects
Pollination is important to maintain diversity in our natural ecosystem and maintain ecosystem health

“Pollination is important to maintain diversity in our natural ecosystem and maintain ecosystem health.” So says Dr Lize Joubert, lecturer in the Department of Plant Sciences at the University of the Free State. “Research helps to understand the interaction between insects and flowers and their many implications on real-world problems.”

Plant systematics and pollination biology, Dr Joubert’s research field, looks at how plants diversify, adapt to environmental changes and how their flowers evolve to keep attracting insects to pollinate them for reproduction. 

Dependency on pollination

Crop production is, in many cases, dependent on pollination. About 75% of the world’s crops are to some extent dependant on pollination. “Pollination is really important for us as human beings, but it is also important to maintain diversity in our natural ecosystem and maintain ecosystem health.”

Dr Joubert obtained her PhD in plant systematics in 2013 and was subsequently awarded the EM van Zinderen-Bakker Prize for an outstanding PhD dissertation in Botany.

She is also the curator of the Geo Potts Herbarium in Bloemfontein, the internationally accredited herbarium housing over 30 000 plant specimens, mainly representing the flora of central South Africa and several special collections from Marion Island, the Okavango Delta, and KwaZulu-Natal. 

Learning from the experts

As a young researcher Dr Joubert became part of the Prestige Scholars Programme (PSP) at the UFS which led her to Cambridge University where she became part of a research group for nearly two years under an expert in her field, Prof Beverley Glover. The PSP at UFS identifies and promotes promising young academics at the university to become full professors with excellent research accomplishments. 

Dr Joubert views the PSP Programme to a large extent as her academic home. She is proud to be part of the programme that has brought her closer to other experts in her field and resulted in collaborations in which she is involved in cutting-edge research. 

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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