plant science – Cabot Institute for the Environment blog

Kyoto and Bristol: Working together on plant science

Posted on October 22, 2014April 14, 2023 by janet.crompton

Last month Bristol’s plant scientists were pleased to welcome visiting researchers from Kyoto University, one of Japan’s leading universities.

The two universities have a strong partnership, which led to large cross-disciplinary symposia in 2013 and 2014. As Dr. Antony Dodd explains, the popularity of the 2014 plant science session led to the emergence of the latest workshop: “The second symposium included a large plant science session that attracted around 50 scientists. Following this, it was decided to expand upon this success and hold a focused three-day plant sciences workshop in the University of Bristol’s new Life Sciences Building”. Bristol’s Dr. Dodd and Professor Simon Hiscock and Kyoto’s Professors Minoru Tamura and Hiroshi Kudoh organised the event, which took place on 23-25 September 2014.


From left, organisers Minoru Tamura, Antony Dodd, Simon Hiscock and Hiroshi Kudoh

Academics, post-docs and (I was pleased to see) several PhD students from Kyoto’s Department of Botany and Center for Ecological Research made the long trip to Bristol. During the talks and poster presentations given by researchers from both Kyoto and Bristol, I was amazed by how similar our research interests were, for example in the areas of circadian rhythms (nature’s body clock), plant shade avoidance and the environmental regulation of the growing plant.
Botanic garden partnership

Plant science at both universities is enhanced by their botanic gardens. During the workshop, visitors from Kyoto had the opportunity for a guided tour of Bristol’s Botanic Garden by its director, Professor Hiscock. Many of us think of the Botanic Garden as somewhere pleasant to spend an afternoon, but it is an important resource for researchers at Bristol and further afield and as Dr. Dodd explains, “Both Kyoto and Bristol have long-standing interests in plant evolution and taxonomy”. At the end of the visit, Professors Hiscock and Tamura, the Director of the Kyoto Botanic Garden, signed a formal partnership between the two botanic gardens. Dr. Dodd expands on the importance of this agreement: “The new partnership between our two Botanic Gardens is very exciting because it will allow us to share good ideas and good practice in curation, cultivation, science and education”.

Professors Tamura and Hiscock sign the botanic
gardens partnership. Image credit: Botanic Gardens

Benefiting from international collaboration

The main aim of the workshop was to form collaborations between Kyoto and Bristol scientists. “The portfolio of techniques, ideas and approaches to academic research varies considerably between countries. International collaboration forms a brilliant way to accomplish science that would not otherwise be possible, by providing access to new techniques, facilities, and ideas”, says Dr. Dodd. The end of the meeting gave researchers a chance to meet with others with similar interests and discuss new ways to work together. Dr. Dodd and Professor Kudoh also announced that they had just won a funding grant to investigate circadian rhythms in the field in Kyoto, which sounded like a fascinating project. One of the aims of the project is a short-term graduate exchange programme, which will give the students a unique chance to learn new techniques and experience international research, forming new collaborations of their own.

I really enjoyed the workshop. It was fantastic to hear about the research underway in Kyoto University and to discuss my own work with people in related fields. It was also interesting to hear about the similarities and differences in academia half the world away. Thanks to the organisers, and I look forward to hearing about the international collaborations that come out of this event soon!

Image credit: Botanic Garden

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This blog is written by Sarah Jose, Cabot Institute, Biological Sciences, University of Bristol

Sarah Jose

Will global food security be affected by climate change?

Posted on September 30, 2013April 20, 2023 by janet.crompton

The Intergovernmental Panel on Climate Change (IPCC) has just released an important report outlining the evidence for past and future climate change. Unfortunately it confirms our fears; climate change is occurring at an unprecedented rate and humans have been the dominant cause since the 1950s. Atmospheric carbon dioxide (CO₂) has reached the highest level for the past 800,000 years, which has contributed to the increased temperatures and extreme weather we have already started to see.

As a plant scientist, I’m interested in the complicated effects that increased temperatures, carbon dioxide and changes in rainfall will have on global food security. Professor David Lobell and Dr Sharon Gourdji wrote about some of the possible effects of climate change on crop yield last year, summarised below alongside IPCC data.

Increased CO₂

Plants produce their food in a process called photosynthesis, which uses the energy of the sun to combine CO₂ and water into sugars (food) and oxygen (a rather useful waste product). The IPCC reports that we have already increased atmospheric CO₂ levels by 40% since pre-industrial times, which means it is at the highest concentration for almost a million years. Much of this has accumulated in the atmosphere (terrible for global warming) or been absorbed into the ocean (causing ocean acidification) however it may be good news for plants.

Lobell and Gourdji wrote that higher rates of photosynthesis are likely to increase growth rates and yields of many crop plants. Unfortunately, rapid growth can actually reduce the yields of grain crops like wheat, rice and maize. The plants mature too quickly and do not have enough time to move the carbohydrates that we eat into their grains.

High temperatures

The IPCC predicts that by the end of the 21st century, temperatures will be 1.5C to 4.5C higher than they were at the start of it. There will be longer and more frequent heat waves and cold weather will become less common.

Extremely high temperatures can directly damage plants, however even a small increase in temperature can impact yields. High temperatures means plants can photosynthesise and grow more quickly, which can either improve or shrink yields depending on the crop species (see above). Lobell and Gourdji noted that milder spring and autumn seasons would extend the growing period for plants into previously frosty times of year allowing new growth periods to be exploited, although heat waves in the summer may be problematic.

Image credit: IPCC AR5 executive summary

Flooding and droughts

In the future, dry regions will become drier whilst rainy places will get wetter. The IPCC predicts that monsoon areas will expand and increase flooding, but droughts will become longer and more intense in other regions.

In flooded areas, waterlogged soils could prevent planting and damage those crops already established. Drought conditions mean that plants close the pores on the leaves (stomata) to prevent water loss, however this means that carbon dioxide cannot enter the leaves for photosynthesis and growth will stop. This may be partly counteracted by the increased carbon dioxide in the air, allowing plants to take in more CO₂ without fully opening their stomata, reducing further water loss and maintaining growth.

Image credit: IPCC AR5 executive summary

These factors (temperature, CO₂ levels and water availability) interact to complicate matters further. High carbon dioxide levels may mean plants need fewer stomata, which would reduce the amount of water they lose to the air. On the other hand, higher temperatures and/or increased rainfall may mean that crop diseases spread more quickly and reduce yields.

Overall Lobell and Gourdji state that climate change is unlikely to result in a net decline in global crop yields, although there will likely be regional losses that devastate local communities. They argue that climate change may prevent the increases in crop yields required to support the growing global population however.

The effect of climate change on global crop yields is extremely complex and difficult to predict, however floods, drought and extreme temperatures will mean that its impact on global food security (“when all people at all times have access to sufficient, safe, nutritious food to maintain a healthy and active life”) will almost certainly be devastating.

On the basis of the IPCC report and the predicted impact of climate change on all aspects of our planet, not just food security, it is critical that we act quickly to prevent temperature and CO₂ levels rising any further.

This blog is written by Sarah Jose, Biological Sciences, University of Bristol

You can follow Sarah on Twitter @JoseSci

Sarah Jose

Neonicotinoids: Are they killing our bees?

Posted on September 11, 2013April 20, 2023 by janet.crompton

The UK government has announced that whilst it accepts the European Union ban on neonicotinoid pesticides, it does not believe that there is enough scientific evidence to support this action.

In April, the EU banned the use of neonicotinoid pesticides for two years starting in December because of concerns over their effect on bees. The use of these pesticides will not be allowed on flowering crops that attract bees or by the general public, however winter crops may still be treated. Fifteen countries voted for this ban, with eight voting against it (including the UK and Germany) and four countries abstaining.

Neonicotinoids were originally thought to have less of an impact on the environment and human health than other leading pesticides. They are systemic insecticides, which means they are transported throughout the plant in the vascular system making all tissues toxic to herbivorous insects looking for an easy meal. The most common application in the UK is to treat seeds before they are sown to ensure that even tiny seedlings are protected against pests.

Image by Kath Baldock

The major concern over neonicotinoids is whether nectar and pollen contains levels of pesticide is high enough to cause problems for bees. It has already been shown that they do not contain a lethal dose, however this is not the full story. Bees live in complex social colonies and work together to ensure that there is enough food for developing larvae and the queen. Since neonicotinoids were introduced in the early 1990s bee populations have been in decline and there is a growing feeling of unease that the two may be connected. Scientific research has provided evidence both for and against a possible link leaving governments, farmers, chemical companies environmentalists and beekeepers in an endless debate about whether or not a ban would save our bees.

Several studies on bees have shown that sublethal levels of neonicotinoids disrupt bee behaviour and memory. These chemicals target nicotinic acetylcholine receptors, one of the major ways that signals are sent through the insect central nervous system. Scientists at Newcastle University recently showed that bees exposed to neonicotinoids were less able to form long-term memories associating a smell with a reward, an important behaviour when foraging for pollen and nectar in the wild.

Researchers at the University of Stirling fed bumble bee colonies on pollen and sugar water laced with neonicotinoids for two weeks to simulate field-like exposure to flowering oil seed rape. When the colonies were placed into the field, those that had been fed the pesticides grew more slowly and produced 85% less queens compared with those fed on untreated pollen and nectar. The production of new queens is vital for bee survival because they start new colonies the next year. Studies in other bee species have found that only the largest colonies produce queens, so if neonicotinoids have even a small effect on colony size it may have a devastating effect on queen production.

So why does the government argue that there is not enough scientific evidence to support a ban on neonicotinoids?

Image by Kath Baldock

In 2012, the Food and Environment Research Agency set up a field trial using bumble bee colonies placed on sites growing either neonicotinoid-treated oil seed rape or untreated seeds. They found no significant difference between the amount of queens produced on each site, although the colonies near neonicotinoid-treated crops grew more slowly. The study also found that the levels of pesticide present in the crops was much lower than previously reported.

I personally think that both laboratory and field studies bring important information to the debate, however neither has the full answer. Whilst more realistic, the government’s field trial suffered from a lack of replication, variation in flowering times and various alternative food sources available to bees. Only 35% of pollen collected by the bees was from the oil seed rape plants, so where oil seed rape comprises the majority of flowering plants available to bees the effect on neonicotinoids may be more pronounced. The laboratory research can control more variables to establish a more clear picture, however the bees in these studies were often given only neonicotinoid-treated pollen and nectar to eat, which clearly is not the case in a rural landscape. Flies and beetles have been shown to avoid neonicotinoids, which could mean that bees would find alternative food sources where possible. This would have a major impact on crop pollination.

We desperately need well-designed field studies looking at the effect of neonicotinoids on bees and the environment in general. Despite an EU moratorium on growing neonicotinoid treated crops, an allowance should be made for scientists to set up controlled field trials to study the effect of these pesticides on bees during the two year ban. It could be our only chance to determine the danger these chemicals pose to vital pollinators and the wider environment.

This blog is written by Sarah Jose, Biological Sciences, University of Bristol

Sarah Jose