Looking good now
The multitude of golden black-eyed Susan is setting the Autumn Garden aglow.
The multitude of golden black-eyed Susan is setting the Autumn Garden aglow.
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Nature's calendar: the Naked Scientists investigate how plants tell the time....

How do plants know when it’s time to pack up and sleep through winter or burst into flower for spring? What are the signs in our weather that the plants are reading and what happens when this process starts early? The award-winning Naked Scientists, one of the world's most popular science shows and based at Cambridge University's Institute of Continuing Education (ICE), have popped down to the Garden in search of early blooms and to investigate the process of hibernation.

The Naked Scientists share their observations and pop their plant questions to Dr Phil Wigge, a group leader at the Sainsbury Laboratory Cambridge University (SLCU), whose research investigates how plants perceive temperature and how these signals are integrated into development.

Dr Wigge says: “Plants are known as ‘sessile organisms’ - so unable to move around freely - and are highly responsive to small differences in temperature. This makes them ideal systems to identify the signal transduction pathways involved in temperature sensing. When to flower is a really important decision that plants must make, and they measure the temperature to help get this right. At the Sainsbury Laboratory some of the research we are doing is analysing how warm temperatures promote flowering.

“Small changes in temperature cause many changes to occur in the plant, for example growth speeds up at higher temperature, and so studying how flowering is affected by temperature may provide answers to wider issues. It is predicted that for every 1 ºC increase in temperature there is a corresponding drop of about 10% in crop yields,” says Dr Wigge. “This raises the interesting prospect that it might be possible to breed plants with optimised temperature responses for particular climates. We are working on several approaches to alter temperature responsiveness in a very precise and controlled way so that we can minimise the downsides of temperature stress on crop yields.”

Back in the Garden, Head of Horticulture, Sally Petitt, is observing how the unusually warm temperatures we have been experiencing are affecting flowering times. She says: “We’re already seeing daffodils in flower which is usually an indicator that spring has arrived.”

When it comes to our own gardens, Sally recommends gardeners give plants showing signs of unseasonal flowering added protection with a fleece wrapping, which will help prevent flowers being damaged. She says: “Unfortunately once the plants natural time clock has been disrupted we can do little to reset it for this year. So, some flowers will flower out of season and not flower again at the usual time. Those which produce a succession of flowers for several months may continue to do so - just rather earlier than normal. If the weather now reverts to that typical of winter the flowers and buds of others may be damaged and they may fail to flower until next year.”

To find out more about the signs and impact of hibernation and temperature change at the Garden, listen out for the Naked Scientist broadcast on BBC Radio Cambridgeshire on Sunday 17 January from 6pm - 7pm; Radio 5Live Saturday 23 January 5am. The podcast will be available from Tuesday evening 19 January or downloadable from www.nakedscientists.com.
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