The systematic beds were covered in a light covering of snow during the guided walks.
With Spring somewhat delayed, the plants in the Garden’s systematic beds were keeping a low profile. Feverfew, one of the featured plants, responds to harsh weather governed by the compound melatonin. This compound is also produced by animals, chemically regulating the sleep-wake cycle by lowering the body temperature and causing drowsiness.
Chemical structure of melatonin, CSD refcode MELATN01
Luckily, the Trail also contains plants in the Glasshouses and some trees which are visible all year round. One of the trees is pine, which contains alpha- and beta-pinenes in its resin. These monoterpenes, which differ in the position of the C-C double bond, are the main constituents of turpentine.
The pine tree afforded me some shelter from the elements as I discussed alpha and beta pinene, extracted from pine tree resin.
In the presence of sunlight, these volatile compounds react with ozone and sulphur acids in the air to produce nanoparticles. These are Rayleigh scatterers and because they scatter blue light more strongly than the other components of sunlight, pine forests are often tinged blue. The resulting blue haze helps keep the trees cool in warm weather- so we didn’t see any evidence of it on our walks!
The Trail is usually at its best from June to October so if you’re planning a visit to Cambridge over the summer, why not have a look? The virtual Trail can be enjoyed all year round and in all weathers!
We hope to run some more walks at next year’s Science Festival. Before that we will be taking part in the “Festival of Plants” at the Garden on Saturday 18th May. Look out for more details nearer the time.