Runny nose and streaming eyes? What's really getting up the nose of hay fever sufferers? What's out there? And why does it matter?
Experts from the Nanoscale and Microscale Research Centre (nmRC) at the University of Nottingham have been doing a bit of detective work to get a microscopic view of the things that make hay fever sufferers sneeze. They collected samples from a range of pollen release stages and put them under their powerful microscopes to show us what is really getting up our noses.
The results are not to be sniffed at! They've produced some stunning images showing, in minute detail, just how complex the act of pollination is.
Dr Beth Steer, Research Technician in the nmRC, said: “These images show in extraordinary detail microscopic particles, and demonstrate how microscale objects have a daily impact on our lives. The environmental SEM used (Quanta 650 ESEM) allowed us to pick catkins straight off the tree and image them fully hydrated, unlike a conventional SEM for which we’d need to dry them, so we can view them as they are with no modifications of the structures. One thing that is clear is how brilliant evolution is at honing natural designs.”
Pollen collection and scanning
Pollen is released from the plant's anther. They collected samples from the air by hanging strips of sticky tape outside for a few hours to see what they could catch. The samples were then imaged with a Scanning Electron Microscope (SEM).
Professor Andrei Khlobystov, Professor of Nanomaterials and Director of the Nottingham nmRC, said: "The typical size of pollen particles starts from a few micrometers to tens of micrometers, which is smaller than the diameter of a single human hair. In order to see these tiny particles properly and to appreciate their shape and intricate surface structure, we have to use a beam of fast electrons instead of light. With a much shorter wavelength than that of light, electrons in the SEM reveal effectively identity the pollen particles under investigation."
Every plant has a characteristic size and shape of pollen with complicated structures on their tough outer exine – their outer coating. This makes it nice and easy for pollen experts – palynologists – to identify them. Once this the pollen lands on the female stigma of the same species it's love at first sight. A pollen tube grows, penetrates and fertilises the plant.
Palynology at Nottingham
Our palynologists are studying pollen to increase food production. Dr Alison Tidy, from the School of Biosciences, said: "Pollen development is especially sensitive to environmental stresses such as heat. Hot days, such as the heat-wave we've experienced this summer, can have a negative impact on the survival of pollen and therefore food production. Part of our research looks at determining lines which are more resistant to changes in the environment in rice, oilseed rape, wheat and barley.
Dr Tidy is part of Professor Zoe Wilson’s team studying the molecular genetic analysis of plant development. They carry out research to understand pollen development and pollen release - in particular, in male sterile lines – lines that do not produce pollen – to enable crossing and hybrid production which can increase resistance to stresses such as heat and pathogens.
"To do this we use a number of different imaging techniques such as SEM and confocal microscopy. We use stains and fluorescent tags to observe differences in mutants to help us discover the roles of genes. We also use molecular biology to look at gene and protein expression in pollen development employing techniques such as quantitative polymerase chain reaction for gene expression (qPCR); western blotting for protein expression; and yeast-1-hybrid for DNA and protein interaction. All these techniques allow us to advance our knowledge in pollen development and help towards direct impact on food production."
SEM images of pollen are available here.
Images for Dr Alison Tidy are available via this link.
The images will be available until Wednesday 8 August 2018.
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Notes to editors:
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