Pollination is a fundamental process in plant biology describing the transfer of pollen from the male to female parts of the plant. In out-crossing plant species this pollen transfer is difficult, often requiring the movement of pollen between plants sometimes across great distances. Plants have evolved a large array of different strategies to overcome these physical barriers using either abiotic or biotic mechanisms such as wind, rain or insects to mobilize pollen. Many of these pollination strategies are affected by external environmental conditions such as seasonal changes and fluctuations in ambient temperature. A second dilemma faced by out-crossing plants is how to limit self-pollination; very often this is achieved by offsetting the maturation timing of the male and female floral organs. Currently there is little information on how plants regulate the timing of floral organ maturation or on how plants perceive changes in the environment and what implications climate change may have on these precisely timed mechanisms or pollination strategies.


The Crop Floral Biology team aims to combine molecular techniques with detailed physiological measurements and time-lapse photography to investigate how changing environments affect plant and flower development, flower physiology, flower health and pollinator visits. We follow these flowers from bud opening to seed development to assess the impact of these weather conditions on plant reproduction and potentially crop yield.


Research Projects

We currently have three big collaborative interdisciplinary projects we are working on in collaboration with UFS, ARC and the Department of Geography at UP:

1. The effects of a changing environment and late-planting dates on maize plant development and yield in South Africa 

- Funded by Maize Trust and DSI through the GrainSA cooperation

2. The impact of heat stress on floral organ development at the physiological and molecular level during anthesis in domesticated sunflower

- Funded by NRF-Thuthuka

3. Assessing the effect of planting date and environment on sunflower development, Sclerotinia head rot and yield 

- Funded by OAC/OPDT



Heritage Day Group Project

To celebrate the diversity and heritages of our team, some of our members have written paragraphs about their research in their home languages. This is an effort to share our research with the wider communities we work within. 

“If you talk to a man in a language he understands, that goes to his head. If you talk to him in his own language, that goes to his heart.”- Nelson Mandela

We hope you to will fall in love with our research!

Uyabongeka Memela (MSc Student)


Lolucwaningo lubhekisisa isitshalo esibalulekile kakhulu kwezolimo esibizwa ngokuthi uBhekilanga. Lesisitshalo sihlakulwa umhlaba wonke ngoba sikhiqiza amafutha ayingqayizivele okupheka, okuyinto yokuqala esaziwa ngayo. Ngobuhle baso namakhanda amakhulu aphuzi, siyaye sisebenze ukuhlobisa. Akupheleli lapho, imbewu yalesisitshalo iyadliwa yodwa njengamakinati iphinde isetshenziselwe ukuthi idliwe izinyoni nezinkukhu. Ukushintsha kwesimo sezulu ngenxa yokufudumala komhlaba sekuyinto esijwayelekile manje. Lokhu kufudumala kudala ukuthi kugcine kunezimo zezulu ezahlukahlukene ngesikhathi esingajwayelekile futhi. Izitshalo kaningi ziyazwela makushintshashintsha isimo sezulu uma zidlula esigabeni zokuzala. Ikakhulu lolucwaningo lubukisisa ukuthi ukushisa kwesimo sezulu lokhu okweqile kuchaphazela kanjani lesisitshalo esiwuBhekilanga kanye nezitho zaso zangasese zokuzala phecelezi i-style, i-stigma kanye ne khwalithi ye mpova nesikhathi ngqo ephuma ngaso, nokuthi kushintsha kanjani indlela izinambuzane ezivakashela ngayo lezizimbali. Ngalendlela kuzoba nolwazi olunzulu lokuthi yini engenziwa kulembewu kaBhekilanga ukuze izokwazi ukumelana nalesimo sezulu esishintshayo njalo, ibe nomkhiqizo ofanayo noma ngabe ikhula kusiphi isimo sezulu.


Olu phando lujolise kwisityalo esibalulekileyo kwezolimo, uJongilanga. uJongilanga sisityalo esityalwa kwihlabathi liphela, isityalo esaziwa ngokuvelisa amafutha okupheka. Esi ke sisizathu sokuqala, sokutyala uJongilanga. Ngenxa yokuqaqamba, nobuhle baso, ikwasiso nesityalo esi setyenziselwa ukuhombisa. Ukwengeza, imbewu yesisityalo ityiwa okwezimuncumuncu, iphinde ibekuko nokutya kweentaka. Ukutshintsha kwesimo sezulu yaba yinto eqhelekileyo. Nangona kunjalo, ubushushu budala iingxaki ngokutshintsha isimo sokuzala kwezityalo. Olu phando lujonga indlela ubushushu bucaphazela ngayo isityalo uJongilanga kumalungu okuzala. Olulwazi, luzakunceda ekwenzeni isityalo uJongilanga, owohlukileyo. UJongilanga lo, uzokwazi ukumelana nobushushu, aqhubeke avelise amafutha la siwadingayo nokuba isimo sezulu sinjani na. Nangaphezulu, oku kunciphisa ukulahleka kwesivuno, uJongilanga.

English translation

This research is about a crop called a Sunflower, which is very important in the agricultural sector. This crop is cultivated worldwide primarily for its ability to produce high quality oil. Sunflower has big yellow flowers, and for that reason it is used as an ornamental plant. Furthermore, its seeds are eaten as a snack and used as bird feed. Climate change takes place due to global warming, which is slowly becoming a norm. The warming of the atmosphere is causing a change in weather patterns. Plants are very sensitive during their reproductive stage. Therefore, this study is investigating how heatwaves affects sunflowers reproductive organs, especially the style, stigma and pollen viability. It is also looking at how heatwaves affect pollinator visitors and the exact timing of pollinator visitors. The results from this study will be useful in a sense that it can provide information that will be used to create a variant that is able to withstand harsh weather conditions and be able to produce stable yields.

Vera Röder (MSc Student)


Gene sind der molekulare Bauplan des Lebens. Indem wir die Gene verstehen, können wir verstehen, warum Lebewesen so handeln und aussehen, wie sie es tun, und wie wir sie verändern können, um bestimmte Aspekte zu verbessern. Eines der größten Probleme unserer Generation ist die drohende Bedrohung des Klimawandels und der globalen Erwärmung. Davon wird jeder betroffen sein, auch unsere Pflanzen und Nahrungspflanzen. Wenn es in Zukunft noch heißer wird, werden viele unserer Nahrungspflanzen unter großem Hitzestress stehen. Eine dieser Nahrungspflanzen sind Sonnenblumen. Die Art und Weise, wie Sonnenblumen auf Hitzestress reagieren, ist noch unbekannt, insbesondere während der Blütezeit. Die Blütezeit ist die Zeit in der die Pflanzen am empfindlichsten auf Stress reagieren, was sich darauf auswirkt, wie viel Saatgut und Öl von Sonnenblumen geerntet werden kann. Ich untersuche, wie sich dieser Hitzestress auf bestimmte Prozesse und Teile der Blüte während der Blüte auswirkt und warum sie sich so verhalten, wie sie es tun. Durch eine Kombination von Feld- und Laborexperimenten kann ich herausfinden, welche zellulären Prozesse Sonnenblumen vor diesem Hitzestress schützen könnten. In Zukunft könnten diese Gene manipuliert werden, um Sonnenblumen und andere blühende Pflanzen zu schützen. Wenn wir wichtige Nahrungspflanzen wie die Sonnenblume nicht gegen künftige Klimaveränderungen schützen, könnte es zu schweren Nahrungsmittelengpässen kommen. Sonnenblumen gehören zu den vier wichtigsten Nahrungspflanzen, die für Speise- und Industrieöl angebaut werden, und sind für die Agrarwirtschaft vieler Länder von entscheidender Bedeutung. Genetische Studien und Entwicklungen von Nahrungspflanzen sind die Zukunft der Landwirtschaft.

English translation

Genes are the molecular blueprint for life. By understanding genes, we can understand why living things act and look the way they do, and how we can change them to improve particular aspects. One of the greatest problems of our generation is the looming threat of climate change and global warming. This will affect everyone, including our plants and crops. As the future gets hotter, many of our crops will be under great heat stress. One of these crops are sunflowers. The way sunflowers react to heat stress is still unknown, especially during flowering. Flowering is when plants are most vulnerable to stressful conditions, and this effects how much seed and oil can be harvested from sunflowers. I am studying how this heat stress effects certain processes and parts of the flower during flowering, and why they act the way they do. Using a combination of experiments in fields and in the lab, I can see which cellular processes might give sunflowers some protection against this heat stress. In the future, these genes could be manipulated to protect sunflowers and other flowering crops. If we don’t safeguard important food crops, such as sunflower, against future climate change conditions, there may be severe food shortages. Sunflower is one of the top four crops grown for edible and industrial oil and is vital for the agricultural economy of many countries. Genetic studies and developments of crops are the future of agriculture.

Renel Groenewald (BSc Honours student)


Klimaatsverandering is ‘n wêreldwye probleem wat plante en allerlei gewasse aantas.  Bevrugting en die voorplantingsorgane word soms meer beskadig deur die toename in temperatuur.  Sonneblomme is ‘n belangrike gewas wat gebruik word om olie te vervaardig, en word geplant in baie lande.  Gene wat verantwoordelik is vir die verandering in plant organe, of wat die verandering veroorsaak, kan geïdentifiseer word deur molukulêre tegnieke.  Sonneblomme het ‘n orgaan wat deel is van die voortplantingstelsel genaamd die styl.  Style druk stuifmeel vanaf die binnekant na die buitekant van die sonneblom-blom sodat bestuiwers, byvoorbeeld insekte, die stuifmeel kan vervoer van een blom na die ander blom en bestuiwing gevolglik kan plaasvind.  Hoër temperature veroorsaak dat die style vinniger na buite gedruk word. Bestuiwers is dan te laat om stuifmeel te ontvang omdat die stuifmeel lank buite die blom is en vergaan. Bestuiwing van ander blomme kan gevolglik nie meer plaasvind nie.  Die gene wat betrokke is by die vinner groei van style moet nog ondersoek word. Een geen wat moontlik verantwoordelik is vir die groei van style is XTH (xylo glucan endo transglycosylase/ hydrolase).  Die geen se uitrukking sal gepaal word in style wat gegroei is onder normale omstandighede.  ‘n Verskil in die kwantiteit van die uitdrukking van die XTH geen is, sal aandui dat moontlik ‘n rol speel in styl ontwikkeling en groei.

English translation

Climate change is a problem worldwide and plants are severely affected. 
Reproductive organs and fertilisation are sometimes influenced more.  Sunflowers are important for oil production and planted in a lot of countries.  Genes in plants can be identified that change or is changed due to heat.  Sunflowers have tissue that form part of their reproduction called styles.  Styles push pollen out of the flower so that pollinators can use the pollen and pollinate other sunflowers for pollination to take place.  Under higher heat styles, emerge quicker and this causes pollinators to reach the styles too late when the pollen can no longer be used to fertilise other sunflowers.  The genes that cause styles to elongate in heat need to be investigated and one possible gene is XTH (xylo glucan endo transglycosylase/ hydrolase). This gene will be screened for in styles from plants that were exposed to high heat and styles from normal conditions.

Dr Robert Mangani (Postdoctoral Fellow)


MuSouth Africa, kudyarwa kwechibage kunofambidzana nekutanga kwekunaya kwemvura mumwaka wezhizha (Moletsi and Walker 2012). Kunonoka kwekunaya kwemvura kunovhiringidza nguva yekudyarwa kwembeu. Izvi zvinokanganisa kukura kwechibage uye zvinogona kukonzera kudzikira kwegoho nembeu zvakanyanya. Kunonoka kudyarwa kwechibage kunoita kuti chibage chikure munguva isingatarisirwe kurima chibage izvo zvinokonzera kudzika kwegoho nenzira dzakasiyana siyana zvichienderana nenzvimbo imwe neimwe uye nezvakatipoteredza. Mumakore achangodarika, goho rechibage muSouth Africa raingoshanduka shanduka, pamwe richiwanda pamwe richiita shoma zvichikonzerwa nekusiyana siyana kwemwaka pagore (DAFF – Agriculture yearbook 2017/2018). Pane fungidziro yekuti kudzikira kwegoho zvakanyanya mumakore ano kwaikonzerwa nekuda kwekunonoka kunaya kwemvura. Donzo redu mutsvakurudzo idzi rakanangana nekuongorora kudyarwa kwechibage muSouth Africa kana kuchinge kwanonoka kunaya, uye nekushanduka kwemamamiriro ekunze. Isu tinotarisira kuwedzera ruzivo ruripo mukushandiswa kwemamodheru ekuongorora zvinoitika kana chibage chichinge chanonoka kudyarwa. Tsvagurudzo iyi inobatsirawo kune zvinangwa zvekusimudzira kupedza nzara uye nekugara vanhu vakagadzirira matambudziko anogona kukonzwera nekukushanduka kushanduka kwemamiriro ekunze.

English translation

In South Africa, maize plantings are largely dependent on the onset of the summer rainy season, with late rains usually result in late plantings (Moletsi and Walker 2012). Late plantings can lead to early plant development under hot mid-summer conditions. This affects plant growth and development and can lead to significant decreases in yield and seed quality. Late plantings push plant development to the edges of the planting window and into sub-optimal conditions that will affect yield in several different ways depending on the growing region and specific environmental factors. In recent years, South Africa’s maize production has become more and more erratic, with increasing inter- and intra-annual variability (DAFF – Agriculture yearbook 2017/2018). There is a perception that this decrease in yield is predominantly due to delayed rains in those seasons. This project aims to investigate late maize plantings in South Africa and its association with late rain, and other extreme weather events. We hope to contribute to current predictive models based on planting date and aim to highlight risk factors through this study. This is an important project, which directly focuses on food security and the threat of climate change in South Africa. The study also contributes to the broader sustainability goals of zero hunger and climate action.

Ofentse Mathibela (PhD Student)


Maemo a bosa a lefatshe a tlile go tlhatlhoga ka 1.5°C-2°C, seo se tlile go tlhobaetsa ntshokuno ya dijalo. Tlhatlhogo ya di thempherature ena le bokgone bago tlisa phetogo ka mokgwa o dijalo di golang, go tloga tsatsi la bojalo, go fitlha ka nako ya kotulo. Tlhatlhogo ya maemo a bosa e dira dijalo di seka di a ungwa fa difitlhile mo nakong ya go nna le maungo. Ditlhatlhogo tse, di fetola nako eo dijalo di tshwanetseng go fetogela kgolong engwe, mme go feletsa go lobilwe maungo. Ditlhoro ke dipeo kgotsa dithoro tse ditswang lelapeng la bojang le le bidiwang Poaceae, ebile dijalo tseno dina le karolo e kgolo mo dijong tsa dinaga tse di tokafaditswengle tseo di sa tokafadiwang. Dijalo tse dina le seabe se se botlhokwa mo go direng dijo tsa maemo a godimo a a thusang ka ditwatsi, kagonne di tletse dikhabohaetereiti, poroteine, mafura, dibitamine le diminirale. Dithuto tse dintsi di bonagaditsegore tlhatlhogo ya maeomo a bosa e nale ditlamorago tse di sa kgatlising mo ntshokunong ya dijalo. Gore re natlafatse tshireletso ya dijo mo lefatsheng, go botlhokwa go tlhaloganya gore thempherature e dira eng mo popegong ya dijalo le ditsela tseo popego e, e ka tlhatlhojwang. Ntlha ya thadiso e, ke go leba diphetogo tseo di diragalang mo popegong ya ditlhoro fa thempherature e tlhatlhoga, le go netefatsa gore ke dithulaganyo dife tse di ka berekisiwang go tlhatlhoba diphetogo tse. Tshedimosetso e, e tlile go thusa balimi go baakanya, maano a a ka thusang go godisa maungo mo tshimong tsa bone.

English translation

Global temperatures are expected to increase by 1.5°C-2°C which will cause a strain in crop production. This is due to the ability of shifted temperatures to directly affect crop phenology. Crop phenology is defined as the physiological development of a crop’s growth from sowing to harvest. Increased temperatures tend to cause infertility in crops at a reproductive stage and shift the timing of various developmental stages leading to decreased yield. Cereals are edible seeds or grains from the grass family, Poaceae and these crops form a great portion in diets of many developing and developed countries. These crops play important roles in the manufacturing of high quality and health benefiting foods which are rich in carbohydrates, proteins, lipids, vitamins and minerals. Several studies have shown that increased global temperatures negatively affect cereal crop production. Depending on which developmental stage heat stress is experienced, there could be moderate to severe yield losses. To improve food security it is important to understand which phenological techniques can be applied to determine how phenology is affected by increased temperatures. The aim of this review is to revisit the phenological changes in cereal crops due increased temperatures and how different techniques assist in tracking these changes.  This knowledge will assist farmers in planning, organizing and timely execution of certain standard and special (preventive and protective) agricultural activities to maximise yield.

Editors: Prof Martin Coetzee (Afrikaans), Prof Almuth Hammerbacher (German), Moloro Mmutlane Malefo (Setswana), Annancietar Gomba (Shona), Kololwetu Cetyiwe (Xhoza and Zulu)

A BIG THANK YOU to all the editors that helped!

New Publications

Robert Mangani, Kpoti M. Gunn, Nicky Creux. (2023) Projecting the effect of climate change on planting date and cultivar choice for South African dryland maize production. Agricultural and Forest Meteorology 341(15):109695. 10.1016/j.agrformet.2023.109695
Marshall CM, Thompson VL, Creux NM, Harmer SL. (2023) The circadian clock controls temporal and spatial patterns of floral development in sunflower. eLife (12):e80984.. 10.7554/eLife.80984
Creux NM, Brown EA, Garner AG, Saeed S, Scher CL, Holalu SV, Yang D, Maloof JN, Blackman BK, Harmer SL. (2021) Flower orientation influences floral temperature, pollinator visits and plant fitness. New Phytologist 10.1111/nph.17627
Malefo M, Mathibela O, Makgopa E, Crampton BG. (2020) Investigating the role of Bowman-Birk serine protease inhibitor in Arabidopsis plants under drought stress. Plant Physiology and Biochemistry 149:286-293. 10.1016/J.PLAPHY.2020.02.007
Mangani R, Tesfamariam E, Engelbrecht CJ, Bellocchi G, Hassen A, Mangani T. (2019) Potential impacts of extreme weather events in main maize (Zea mays L.) producing areas of South Africa under rainfed conditions. Regional Environmental Change 10.1007/s10113-019-01486-8