̽��ֱ�� of Cambridge - flowers

Flowers use adjustable ‘paint by numbers’ petal designs to attract pollinators

Anonymous — Fri, 13 Sep 2024 18:00:51 +0000

̽��ֱ��study, by researchers at the ̽��ֱ�� of Cambridge’s Sainsbury Laboratory also found that bees prefer larger bullseyes over smaller ones and fly 25% faster between artificial flower discs with larger bullseyes – potentially boosting efficiency for both bees and blossoms.

Patterns on the flowers of plants guide insects, like bees, to the centre of the flower, where nectar and pollen await, enhancing the plant's chances of successful pollination. Despite their importance, surprisingly little is known about how these petal patterns form and how they have evolved into the vast diversity we see today, including spots, stripes, veins, and bullseyes.

Using a small hibiscus plant as a model, researchers compared closely related plants with the same flower size but three differently sized bullseye patterns featuring a dark purple centre surrounded by white – H. richardsonii (small bullseye covering 4% of the flower disc), H. trionum (medium bullseye covering 16%) and a transgenic line (mutation) of H. trionum (large bullseye covering 36%).

They found that a pre-pattern is set up on the petal surface very early in the flower’s formation long before the petal shows any visible colour. ̽��ֱ��petal acts like a 'paint-by-numbers' canvas, where different regions are predetermined to develop specific colours and textures long before they start looking different from one another.

̽��ֱ��research also shows plants can precisely control and modify the shape and size of these patterns using multiple mechanisms, with possible implications for plant evolution. By fine-tuning these designs, plants may gain a competitive advantage in the contest to attract pollinators or maybe start attracting different species of insects.

These findings are published in Science Advances.

Dr Edwige Moyroud, who leads a research team studying the mechanisms underlying pattern formation in petals, explained: “If a trait can be produced by different methods, it gives evolution more options to modify it and create diversity, similar to an artist with a large palette or a builder with an extensive set of tools. By studying how bullseye patterns change, what we are really trying to understand is how nature generates biodiversity.”

Lead author Dr Lucie Riglet investigated the mechanism behind hibiscus petal patterning by analysing petal development in the three hibiscus flowers that had the same total size but different bullseye patterns.

3_hibiscus_bullseyes-2-01-01_sml.jpg

She found that the pre-pattern begins as a small, crescent-shaped region long before the bullseye is visible on tiny petals less than 0.2mm in size.

Dr Riglet said: “At the earliest stage we could dissect, the petals have around 700 cells and are still greenish in colour, with no visible purple pigment and no difference in cell shape or size. When the petal further develops to 4000 cells, it still does not have any visible pigment, but we identified a specific region where the cells were larger than their surrounding neighbours. This is the pre-pattern.”

These cells are important because they mark the position of the bullseye boundary, the line on the petal where the colour changes from purple to white – without a boundary there is no bullseye!

A computational model developed by Dr Argyris Zardilis provided further insights, and combining both computational models and experimental results, the researchers showed that hibiscus can vary bullseye dimensions very early during the pre-patterning phase or modulate growth in either region of the bullseye, by adjusting cell expansion or division, later in development.

Dr Riglet then compared the relative success of the bullseye patterns in attracting pollinators using artificial flower discs that mimicked the three different bullseye dimensions. Dr Riglet explained: “ ̽��ֱ��bees not only preferred the medium and larger bullseyes over the small bullseye, they were also 25% quicker visiting these larger flower discs. Foraging requires a lot of energy and so if a bee can visit 4 flowers rather than 3 flowers in the same time, then this is probably beneficial for the bee, and also the plants.”

̽��ֱ��researchers think that these pre-patterning strategies could have deep evolutionary roots, potentially influencing the diversity of flower patterns across different species. ̽��ֱ��next step for the research team is to identify the signals responsible for generating these early patterns and to explore whether similar pre-patterning mechanisms are used in other plant organs, such as leaves.

This research not only advances our understanding of plant biology but also highlights the intricate connections between plants and their environments, showing how precise natural designs can play a pivotal role in the survival and evolution of species.

For example, H. richardsonii, which has the smallest bullseye of the three hibiscus plants studied in this research, is a critically endangered plant native to New Zealand. H. trionum is also found in New Zealand, but not considered to be native, and is widely distributed across Australia and Europe and has become a weedy naturalised plant in North America. Additional research is needed to determine whether the larger bullseye size helps H. trionum attract more pollinators and enhance its reproductive success.

Reference
Lucie Riglet, Argyris Zardilis, Alice L M Fairnie, May T Yeo, Henrik Jönsson and Edwige Moyroud (2024) Hibiscus bullseyes reveal mechanisms controlling petal pattern proportions that influence plant-pollinator interactions. Science Advances. DOI: 10.1126/sciadv.adp5574

Flowers like hibiscus use an invisible blueprint established very early in petal formation that dictates the size of their bullseyes – a crucial pre-pattern that can significantly impact their ability to attract pollinating bees.

If a trait can be produced by different methods, it gives evolution more options to modify it and create diversity, similar to an artist with a large palette or a builder with an extensive set of tools

Edwige Moyroud

Bumblebees prefer bigger targets

Lucie Riglet

Artificial flower discs designed to mimic the bullseye sizes of the three hibiscus flowers

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Licence type:

Attribution

UK plants flowering a month earlier due to climate change

sc604 — Wed, 02 Feb 2022 00:08:32 +0000

Using a citizen science database with records going back to the mid-18th century, a research team led by the ̽��ֱ�� of Cambridge has found that the effects of climate change are causing plants in the UK to flower one month earlier under recent global warming.

̽��ֱ��researchers based their analysis on more than 400,000 observations of 406 plant species from Nature’s Calendar, maintained by the Woodland Trust, and collated the first flowering dates with instrumental temperature measurements.

They found that the average first flowering date from 1987 to 2019 is a full month earlier than the average first flowering date from 1753 to 1986. ̽��ֱ��same period coincides with accelerating global warming caused by human activities. ̽��ֱ��results are reported in Proceedings of the Royal Society B.

While the first spring flowers are always a welcome sight, this earlier flowering can have consequences for the UK’s ecosystems and agriculture. Other species that synchronise their migration or hibernation can be left without the flowers and plants they rely on – a phenomenon known as ecological mismatch – which can lead to biodiversity loss if populations cannot adapt quickly enough.

̽��ֱ��change can also have consequences for farmers and gardeners. If fruit trees, for example, flower early following a mild winter, entire crops can be killed off if the blossoms are then hit by a late frost.

While we can see the effects of climate change through extreme weather events and increasing climate variability, the long-term effects of climate change on ecosystems are more subtle and are therefore difficult to recognise and quantify.

“We can use a wide range of environmental datasets to see how climate change is affecting different species, but most records we have only consider one or a handful of species in a relatively small area,” said Professor Ulf Büntgen from Cambridge’s Department of Geography, the study’s lead author. “To really understand what climate change is doing to our world, we need much larger datasets that look at whole ecosystems over a long period of time.”

̽��ֱ��UK has such a dataset: since the 18th century, observations of seasonal change have been recorded by scientists, naturalists, amateur and professional gardeners, as well as organisations such as the Royal Meteorological Society. In 2000, the Woodland Trust joined forced with the Centre for Ecology & Hydrology and collated these records into Nature’s Calendar, which currently has around 3.5 million records going back to 1736.

“Anyone in the UK can submit a record to Nature’s Calendar, by logging their observations of plants and wildlife,” said Büntgen. “It’s an incredibly rich and varied data source, and alongside temperature records, we can use it to quantify how climate change is affecting the functioning of various ecosystem components across the UK.”

For the current study, the researchers used over 400,000 records from Nature’s Calendar to study changes in 406 flowering plant species in the UK, between 1753 and 2019. They used observations of the first flowering date of trees, shrubs, herbs and climbers, in locations from the Channel Islands to Shetland, and from Northern Ireland to Suffolk.

̽��ֱ��researchers classified the observations in various ways: by location, elevation, and whether they were from urban or rural areas. ̽��ֱ��first flowering dates were then compared with monthly climate records.

To better balance the number of observations, the researchers divided the full dataset into records until 1986, and from 1987 onwards. ̽��ֱ��average first flowering advanced by a full month, and is strongly correlated with rising global temperatures.

“ ̽��ֱ��results are truly alarming, because of the ecological risks associated with earlier flowering times,” said Büntgen. “When plants flower too early, a late frost can kill them – a phenomenon that most gardeners will have experienced at some point. But the even bigger risk is ecological mismatch. Plants, insects, birds and other wildlife have co-evolved to a point that they’re synchronised in their development stages. A certain plant flowers, it attracts a particular type of insect, which attracts a particular type of bird, and so on. But if one component responds faster than the others, there’s a risk that they’ll be out of synch, which can lead species to collapse if they can’t adapt quickly enough.”

Büntgen says that if global temperatures continue to increase at their current rate, spring in the UK could eventually start in February. However, many of the species that our forests, gardens and farms rely on could experience serious problems given the rapid pace of change.

“Continued monitoring is necessary to ensure that we better understand the consequences of a changing climate,” said co-author Professor Tim Sparks from Cambridge’s Department of Zoology. “Contributing records to Nature’s Calendar is an activity that everyone can engage in.”

̽��ֱ��research was supported in part by the European Research Council, the Fritz and Elisabeth Schweingruber Foundation, and the Woodland Trust.

Reference:
Ulf Büntgen et al. ‘Plants in the UK flower a month earlier under recent warming.’ Proceedings of the Royal Society B (2022). DOI: 10.1098/rspb.2021.2456

Climate change is causing plants in the UK to flower a month earlier on average, which could have profound consequences for wildlife, agriculture and gardeners.

To really understand what climate change is doing to our world, we need much larger datasets that look at whole ecosystems over a long period of time

Ulf Büntgen

Crab apple tree in bloom

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Petals produce a 'blue halo' that helps bees find flowers

fpjl2 — Wed, 18 Oct 2017 09:54:15 +0000

Latest research has found that several common flower species have nanoscale ridges on the surface of their petals that meddle with light when viewed from certain angles.

These nanostructures scatter light particles in the blue to ultraviolet colour spectrum, generating a subtle optical effect that scientists have christened the ‘blue halo’.

By manufacturing artificial surfaces that replicated ‘blue halos’, scientists were able to test the effect on pollinators, in this case foraging bumblebees. They found that bees can see the blue halo, and use it as a signal to locate flowers more efficiently.

While the ridges and grooves on a petal surface line up next to each other “like a packet of dry spaghetti”, when analysing different flower species the researchers discovered these striations vary greatly in height, width and spacing – yet all produce a similar ‘blue halo’ effect.

In fact, even on a single petal these light-manipulating structures were found to be surprisingly irregular. This is a phenomenon physicists describe as ‘disorder’.

̽��ֱ��researchers conclude that these “messy” petal nanostructures likely evolved independently many times across flowering plants, but reached the same luminous outcome that increases visibility to pollinators – an example of what’s known as ‘convergent evolution’.

̽��ֱ��study was conducted by a multidisciplinary team of scientists from the ̽��ֱ�� of Cambridge’s departments of plant sciences, chemistry and physics along with colleagues from the Royal Botanic Gardens Kew and the Adolphe Merkele Institute in Switzerland.

̽��ֱ��findings are published today in the journal Nature.

“We had always assumed that the disorder we saw in our petal surfaces was just an accidental by-product of life – that flowers couldn’t do any better,” said senior author Prof Beverley Glover, plant scientist and director of Cambridge’s Botanic Garden.

“It came as a real surprise to discover that the disorder itself is what generates the important optical signal that allows bees to find the flowers more effectively.”

“As a biologist, I sometimes find myself apologising to physicist colleagues for the disorder in living organisms – how generally messy their development and body structures can seem.”

“However, the disorder we see in petal nanostructures appears to have been harnessed by evolution and ends up aiding floral communication with bees,” Glover said.

All flowering plants belong to the ‘angiosperm’ lineage. Researchers analysed some of the earliest diverging plants from this group, and found no halo-producing petal ridges.

However, they found several examples of halo-producing petals among the two major flower groups (monocots and eudicots) that emerged during the Cretaceous period over 100 million years ago – coinciding with the early evolution of flower-visiting insects, in particular nectar-sucking bees.

“Our findings suggest the petal ridges that produce ‘blue halos’ evolved many times across different flower lineages, all converging on this optical signal for pollinators,” said Glover.

Species which the team found to have halo-producing petals included Oenothera stricta (a type of Evening Primrose), Ursinia speciosa (a member of the Daisy family) and Hibiscus trionum (known as ‘Flower-of-the-hour’).

All the analysed flowers revealed significant levels of apparent ‘disorder’ in the dimensions and spacing of their petal nanostructures.

“ ̽��ֱ��huge variety of petal anatomies, combined with the disordered nanostructures, would suggest that different flowers should have different optical properties,” said Dr Silvia Vignolini, from Cambridge’s Department of Chemistry, who led the study’s physics team.

“However, we observed that all these petal structures produce a similar visual effect in the blue-to-ultraviolet wavelength region of the spectrum – the blue halo.”

Previous studies have shown that many species of bee have an innate preference for colours in the violet-blue range. However, plants do not always have the means to produce blue pigments.

“Many flowers lack the genetic and biochemical capability to manipulate pigment chemistry in the blue to ultraviolet spectrum,” said Vignolini. “ ̽��ֱ��presence of these disordered photonic structures on their petals provides an alternative way to produce signals that attract insects.”

̽��ֱ��researchers artificially recreated ‘blue halo’ nanostructures and used them as surfaces for artificial flowers. In a “flight arena” in a Cambridge lab, they tested how bumblebees responded to surfaces with and without halos.

Their experiments showed that bees can perceive the difference, finding the surfaces with halos more quickly – even when both types of surfaces were coloured with the same black or yellow pigment.

Using rewarding sugar solution in one type of artificial flower, and bitter quinine solution in the other, the scientists found that bees could use the blue halo to learn which type of surface had the reward.

“Insect visual systems are different to human ones,” explains Edwige Moyroud, from Cambridge’s Department of Plant Sciences and the study’s lead author. “Unlike us, bees have enhanced photoreceptor activity in the blue-UV parts of the spectrum.”

“Humans can identify some blue halos – those emanating from darkly pigmented flowers. For example the ‘black’ tulip cultivar, known as ‘Queen of the night’.”

“However, we can’t distinguish between a yellow flower with a blue halo and one without – but our study found that bumblebees can,” she said.

̽��ֱ��team say the findings open up new opportunities for the development of surfaces that are highly visible to pollinators, as well as exploring just how living plants control the levels of disorder on their petal surfaces. “ ̽��ֱ��developmental biology of these structures is a real mystery,” added Glover.

New study finds “messy” microscopic structures on petals of some flowers manipulate light to produce a blue colour effect that is easily seen by bee pollinators. Researchers say these petal grooves evolved independently multiple times across flowering plants, but produce the same result: a floral halo of blue-to-ultraviolet light.

̽��ֱ��disorder we see in petal nanostructures appears to have been harnessed by evolution and ends up aiding floral communication with bees

Beverley Glover

Tobias Wenzel/ Edwige Moyroud

Top: petals of Ursinia speciosa, a daisy, contain a dark pigment that appears blue due to 'disordered' striations. Bottom: close-up top and side view of microscopic striations.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Opinion: ̽��ֱ��flower breeders who sold X-ray lilies and atomic marigolds

Anonymous — Tue, 24 May 2016 09:35:24 +0000

̽��ֱ��Chelsea Flower Show, one of the biggest and best known horticultural shows in the world, is now open. In the coming days, some 150,000 visitors will make their way to the Royal Hospital Chelsea, expecting to be wowed by innovative garden designs and especially by gorgeous flowers. Among other things, show-goers will have a chance to learn the winner of the Royal Horticultural Society’s Plant of the Year award. This annual prize goes to the “most inspiring new plant” on display at the show – a high honour indeed given the number and range of varieties introduced each year.

̽��ֱ��relentless pursuit of showy flowers for garden display extends back significantly further than the 104 years of the Chelsea show. One need only recall the infamous Dutch tulip craze of the 17th century to be reminded that fascination with floral novelties has a long and storied history.

Over the centuries, entrepreneurial cultivators have endeavoured to create unique plant varieties, either by bringing together the genetic material from established lines through hybridisation or through the discovery of new genetic variation such as a chance mutation in a field. Today, flower breeding is pursued with a far better understanding of plant biology than ever before, in some cases with the aid of technologies such as tissue culture and genetic transformation. Yet the goal remains the same: the creation of tantalising tulips, ravishing roses, show-stopping snapdragons and myriad other plants that will ideally prove irresistible to gardeners and turn a handsome profit.

̽��ֱ��quest to produce profitable new varieties – and to do so as fast as possible – at times led to breeders to embrace methods that today seem strange. There is no better illustration of this than the mid-century output of one of America’s largest flower-and-vegetable-seed companies, W Atlee Burpee & Co.

Gardening with X-rays

In 1941, Burpee Seed introduced a pair of calendula flowers called the “X-Ray Twins”. ̽��ֱ��company president, David Burpee, claimed that these had their origins in a batch of seeds exposed to X-rays in 1933 and that the radiation had generated mutant types, from which the “X-Ray Twins” were eventually developed.

At the time, Burpee was not alone in exploring whether X-rays might facilitate flower breeding. Geneticists had only recently come to agree that radiation could lead to genetic mutation: the possibilities for creating variation “on demand” now seemed boundless. Some breeders even hoped that X-ray technologies would help them press beyond existing biological limits.

̽��ֱ��Czech-born horticulturist Frank Reinelt thought that subjecting bulbs to radiation might help him produce an elusive red delphinium. Unfortunately, the experiment did not produce the hoped-for hue. Greater success was achieved by two engineers at the General Electric Research Laboratory, who produced – and patented – a new variety of lily as a result of their experiments in X-ray breeding.

Though Reinelt’s and other breeders' tangles with X-ray technology resulted in woefully few marketable plant varieties, David Burpee remained keen on testing new techniques as they appeared on the horizon. He was especially excited about methods that, like X-ray irradiation, promised to generate manifold genetic mutations. He thought these would transform plant breeding by making new inheritable traits – the essential foundation of a novel flower variety – available on demand. He estimated that “in his father’s time” a breeder chanced on a mutation “once in every 900,000 plants”. He and his breeders, by comparison, equipped with X-rays, UV-radiation, chemicals, and other mutation-inducing methods, could "turn them out once in every 900 plants. Or oftener”.

Scientific sales pitches

A 1973 Burpee cover. Burpee, CC BY-NC-ND

Burpee’s numbers were hot air, but in a few cases plant varieties produced through such methods did prove hot sellers. In the late 1930s Burpee breeders began experimentation with a plant alkaloid called colchicine, a compound that sometimes has the effect of doubling the number of chromosomes in a plant’s cells. They exploited the technique to create new varieties of popular garden flowers such as marigold, phlox, zinnia, and snapdragons.

All were advertised as larger and hardier as a result of their chromosome reconfiguration – and celebrated by the company as the products of “chemically accelerated evolution”. ̽��ֱ��technique proved particularly successful with snapdragons, giving rise to a line of "Tetra Snaps” that were by the mid-1950s the best-selling varieties of that flower in the United States.

Burpee’s fascination with (in his words) “shocking mother nature” to create novel flowers for American gardeners eventually led him to explore still more potent techniques for generating inheritable variation. He even had some of the company’s flower beds seeded with radioactive phosphorus in the 1950s. These efforts do not appear to have led to any new varieties – Burpee Seed never hawked an “atomic-bred” flower – but the firm’s experimentation with radiation did result in a new Burpee product. Beginning in 1962, they offered for sale packages of “atomic-treated” marigold seeds, from which home growers might expect to grow a rare white marigold among other oddities.

Burpee was, above all, a consummate showman and a master salesman. His enthusiasm for the use of X-rays, chemicals, and radioisotopes in flower breeding emerged as much from his knowledge that these methods could be effectively incorporated into sales pitches as from his interest in more efficient and effective breeding. Many of his mid-century consumers wanted to see the latest science and technology at work in their gardens, whether in the form of plant hormones, chemical treatments, or varieties produced through startling new techniques.

Times have changed, 60-odd years later. Chemicals and radiation are as more often cast as threatening than benign, and it is likely that many of today’s visitors to the Chelsea Flower Show hold a different view about the kinds of breeding methods they’d like to see employed on their garden flowers. But as the continued popularity of the show attests, their celebration of flower innovations and the human ingenuity behind these continues, unabated.

Helen Anne Curry, Peter Lipton Lecturer in History of Modern Science and Technology, ̽��ֱ�� of Cambridge

This article was originally published on ̽��ֱ��Conversation. Read the original article.

̽��ֱ��opinions expressed in this article are those of the individual author(s) and do not represent the views of the ̽��ֱ�� of Cambridge.

Helen Anne Curry (Department of History and Philosophy of Science) discusses the history of our fascination with floral novelties.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

For image use please see separate credits above.

Yes

Cambridge ̽��ֱ�� Botanic Garden Festival of Plants

jeh98 — Tue, 10 May 2016 14:20:48 +0000

Set in the Garden’s 40 acres, the Festival of Plants celebrates all things plant as it hosts a range of activities, tours and events including: hands-on plant science activities and plant-themed pop-up museum family fun; displays of carnivorous plants and orchids; free tours of the Garden and bite-size plant science talks. Horticultural experts will be on hand to answer plant queries and offer advice including tips on vegetable growing and composting and there will be specialist plant stalls, pop-up food stalls and musical entertainment on the Garden’s Main Lawn.

̽��ֱ��aim of the Botanic Garden’s Festival of Plants is to provide visitors with an opportunity to find out more about the plants the Garden grows and the science they support as well as exciting plant and conservation projects happening in Cambridge. ̽��ֱ��day also offers a chance to interact with scientists from across the ̽��ֱ�� working on plant-based solutions to global problems.

Professor Beverley Glover, Director of the Botanic Garden says: "This is the fourth year we’re holding the Festival of Plants. It’s an important day for the Garden where we bring the wonders of the plant world into focus. May is one of the most promising and beautiful months of the year to visit British gardens – the spring tulips are still out, joined by irises and the early summer flowers, creating a crescendo of colour as the days become longer and the temperatures begin to climb. ̽��ֱ�� ̽��ֱ�� Botanic Garden, here in the heart of Cambridge, is no exception, and in spring we particularly celebrate our flowering trees as well as our herbaceous plants.

However, the Botanic Garden is not just about the beauty of plants; it is an important focus for plant science research, particularly in Cambridge, but also around the world. ̽��ֱ��Garden’s collection of 8000 species is used by researchers investigating how plants work, how they evolved, how they are related to each other, and how they can be used to address global problems as challenging as food security and climate change. Some of the species we grow are the focus of conservation projects because they are so rare while some are the focus of projects to extend the range and yield of important crops."

Botanic gardens and plant scientists play a crucial role in addressing the global concerns the world faces today.

Beverley continues: " ̽��ֱ��first two decades of the 21st century have been marked by a growing realisation that only scientific research, and particularly research focused on the plants we depend on for food and shelter, can tackle the global problems that face mankind. These issues were brought to public attention in 2009 when Professor John Beddington, then the UK government's chief scientific advisor, talked of a "perfect storm" resulting from shortages of food, energy and water. Botanic gardens are in the unique position of being able to supply researchers with access to an enormous diversity of plant species, and it is both a privilege and a challenge to support scientific research that aims to solve these problems."

Events will include free garden tours, drop-in talk throughout the day, the Cambridge Orchid Society Annual Show, and a Pop-up Science Marquee on the Main Lawn, where groups from the ̽��ֱ��’s Plant Science department, Sainsbury Laboratory, Global Food Security, Natural Material Group and others demonstrate and explain the wonders of plants with hands on experiments and interactive games designed to highlight how world-leading research can help address global challenges.

You can find an interactive map of the Botanic Garden and the Festival of Plants events here.

Cambridge ̽��ֱ�� Botanic Garden is holding its annual Festival of Plants on Saturday 14 May 2016, offering something for everyone to enjoy: from families to photographers, gardeners to budding plant scientists or anyone looking for an interesting day out in beautiful surroundings.

May is one of the most promising and beautiful months of the year to visit British gardens – the spring tulips are still out, joined by irises and the early summer flowers, creating a crescendo of colour

Beverley Glover

Cambridge ̽��ֱ�� Botanic Garden

Festival of Plants

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Flowers tone down the iridescence of their petals and avoid confusing bees

jeh98 — Thu, 25 Feb 2016 17:04:02 +0000

Iridescent flowers are never as dramatically rainbow-coloured as iridescent beetles, birds or fish, but their petals produce the perfect signal for bees, according to a new study published today in Current Biology.

Bees buzzing around a garden, looking for nectar, need to be able to spot flower petals and recognise which coloured flowers are full of food for them. Professor Beverley Glover from the ̽��ֱ�� of Cambridge’s Department of Plant Sciences and Dr Heather Whitney from the ̽��ֱ�� of Bristol found that iridescence – the shiny, colour-shifting effect seen on soap bubbles – makes flower petals more obvious to bees, but that too much iridescence confuses bees’ ability to distinguish colours.

Whitney, Glover and their colleagues found that flowers use more subtle, or imperfect, iridescence on their petals, which doesn’t interfere with the bees’ ability to distinguish subtly different colours, such as different shades of purple. Perfect iridescence, for example as found on the back of a CD, would make it more difficult for bees to distinguish between subtle colour variations and cause them to make mistakes in their flower choices.

“In 2009 we showed that some flowers can be iridescent and that bees can see that iridescence, but since then we have wondered why floral iridescence is so much less striking than other examples of iridescence in nature,” says Glover. “We have now discovered that floral iridescence is a trade-off that makes flower detection by bumblebees easier, but won’t interfere with their ability to recognise different colours.”

Bees use ‘search images’, based on previously-visited flowers, to remember which coloured flowers are a good source of nectar.

“On each foraging trip a bee will usually retain a single search image of a particular type of flower,” explains Glover, “so if they find a blue flower that is rich in nectar, they will then visit more blue flowers on that trip rather than hopping between different colours. If you watch a bee on a lavender plant, for example, you’ll see it visit lots of lavender flowers and then fly away – it won’t usually move from a lavender flower to a yellow or red flower.”

This colour recognition is vital for both the bees and the plants, which rely on the bees to pollinate them. If petals were perfectly iridescent, then bees could struggle to identify and recognise which colours are worthwhile visiting for nectar – instead, flowers have developed an iridescence signal that allows them to talk to bees in their own visual language.

̽��ֱ��researchers created replica flowers that were either perfectly iridescent (using a cast of the back of a CD), imperfectly iridescent (using casts of natural flowers), or non-iridescent. They then tested how long it took for individual bees to find the flowers.

They found that the bees were much quicker to locate the iridescent flowers than the non-iridescent flowers, but it didn’t make a difference whether the flowers were perfectly or imperfectly iridescent. ̽��ֱ��bees were just as quick to find the replicas modelled on natural petals as they were to find the perfectly iridescent replicas.

When they tested how fast the bees were to find nectar-rich flowers amongst other, similarly-coloured flowers, they found that perfect iridescence impeded the bees’ ability to distinguish between the flowers – the bees were often confused and visited the similarly-coloured flowers that contained no nectar. However, imperfect iridescence, found on natural petals, didn’t interfere with this ability, and the bees were able to successfully locate the correct flowers that were full of nectar.

“Bees are careful shoppers in the floral supermarket, and floral advertising has to tread a fine line between dazzling its customers and being recognisable,” says Lars Chittka from Queen Mary ̽��ֱ�� of London, another co-author of the study.

“To our eyes most iridescent flowers don’t look particularly striking, and we had wondered whether this is simply because flowers aren’t very good at producing iridescence,” says Glover. “But we are not the intended target – bees are, and they see the world differently from humans.”

“There are lots of optical effects in nature that we don’t yet understand. We tend to assume that colour is used for either camouflage or sexual signalling, but we are finding out that animals and plants have a lot more to say to the world and to each other.”

Glover and her colleagues are now working towards developing real flowers that vary in their amount of iridescence so that they can examine how bees interact with them.

“ ̽��ֱ��diffraction grating that the flowers produce is not as perfectly regular as those we can produce on things like CDs, but this 'advantageous imperfection' appears to benefit the flower-bee interaction,” says Whitney.

Reference: Whitney, Heather et al “Flower Iridescence Increases Object Detection in the Insect Visual System without Compromising Object Identity” Current Biology (2016). DOI: https://dx.doi.org/10.1016/j.cub.2016.01.026

Professor Glover will be giving the talk 'Can we improve crop pollination by breeding better flowers?' at the Cambridge Science Festival on Sunday 20 March 2016. More information can be found here: http://www.sciencefestival.cam.ac.uk/events/can-we-improve-crop-pollinat...

Inset images: Iridescent flower (Copyright Howard Rice); Bee on non-iridescent flower (Edwige Moyroud); Bee on non-iridescent flower (Edwige Moyroud).

Latest research shows that flowers’ iridescent petals, which may look plain to human eyes, are perfectly tailored to a bee’s-eye-view.

There are lots of optical effects in nature that we don’t yet understand... we are finding out that animals and plants have a lot more to say to the world and to each other

Beverley Glover

Bee on a non-iridescent flower

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Why buttercups reflect yellow on chins

gm349 — Wed, 14 Dec 2011 08:00:54 +0000

Scientists have found that the distinctive glossiness of the buttercup flower (Ranunculus repens), which children like to shine under the chin to test whether their friends like butter, is related to its unique anatomical structure. Their findings were published today, 14 December, in the Royal Society journal Interface.

̽��ֱ��researchers discovered that the buttercup petal’s unique bright and glossy appearance is the result of the interplay between its different layers. In particular, the strong yellow reflection responsible for the chin illumination is mainly due to the epidermal layer of the petal that reflects yellow light with an intensity that is comparable to glass.

Scientists have been interested in how the buttercup flower works for over a century. They have previously shown that the reflected colour is yellow due to the absorption of the colours in the blue-green region of the spectrum by the carotenoid pigment in the petals. As the blue-green light is absorbed, the light in the other spectral regions (in this case, primarily yellow) is reflected. It has also been known for many years that the epidermal layer of the petals is composed of very flat cells, providing strong reflection.

This new study shows how the buttercup’s exceptionally bright appearance is a result of a special feature of the petal structure. ̽��ֱ��epidermal layer of cells has not one but two extremely flat surfaces from which light is reflected. One is the top of the cells, the other exists because the epidermis is separated from the lower layers of the petal by an air gap. Reflection of light by the smooth surface of the cells and by the air layer effectively doubles the gloss of the petal, explaining why buttercups are so much better at reflecting light under your chin than any other flower.

̽��ֱ��researchers, who were funded by the Leverhulme Trust and the EPSRC, also found that the buttercup reflects a significant amount of UV light. As many pollinators, including bees, have eyes sensitive in the UV region, this provides insight into how the buttercup uses its unique appearance to attract insects.

Dr Silvia Vignolini, from the ̽��ֱ�� of Cambridge’s Department of Physics (Cavendish Laboratory), explained the importance of the buttercup’s unique appearance: “Although many different factors, such as scent and temperature, influence the relationships between pollinators and flowers, the visual appearance of flowers is one of the most important factors in this communication. Flowers develop brilliant colour, or additional cues, such as glossiness - in the case of the buttercup - that contribute to make the optical response of the flower unique. Moreover, the glossiness might also mimic the presence of nectar droplets on the petals, making them that much more attractive.”

Dr Beverley Glover, Department of Plant Sciences, said: “This phenomenon has intrigued scientists and laymen alike for centuries. Our research provides exciting insight into not only a children’s game but also into the lengths to which flowers will go to attract pollinators.”

Professor Ulli Steiner, from the Nanophotonics Centre at the Cavendish Laboratory, the ̽��ֱ�� of Cambridge’s Department of Physics, said: “It is fun to revisit a problem that is more than one century old and, using modern methods, discover something new. ̽��ֱ��strong collaboration between Physics and the Plant Sciences has enabled this.”

Scientists discover why buttercups reflect yellow on chins – and it doesn’t have anything to do with whether you like butter. ̽��ֱ��new research sheds light on children’s game and provides insight into pollination.

Our research provides exciting insight into not only a children’s game but also into the lengths to which flowers will go to attract pollinators.

Dr Beverley Glover, Department of Plant Sciences

Photo Silvia Vignolini

Buttercup under chin

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