Saturday, 5 March 2011

Leaves have less holes but that's not a good thing


I have a few 'considered' postings to come before I leave Sydney at the end of March: two current radio blogs and a couple more from the radio archives (ones I missed in my first sweep). Then, I'll need to concentrate on moving home and catching planes for a while.

But occasionally I'll see, or be directed to, interesting plant stories on the internet so I might just post a few quick references so you and I don't lose track of them.

This one from Jim Croft is about a discovery that the number of stomata in some leaves has dropped by a third from what they had 150 years or so ago. Your can read more at EcoSeed.

Stomata are the breathing holes for plants. Mostly they let carbon dioxide in and oxygen out, as well as allowing water to be 'transpired'. At night most plants take in oxygen and let out carbon dioxide, and sometimes they close these breathing holes to stop water being lost.

The plants sampled grew in Florida, or once grew in Florida (and elsewhere). Collections of preserved plants, held in Herbaria, as well as plants preserved in peat gave the researchers a window into the past.

100 to 150 years ago was when industrialisation led to a sudden increase in carbon dioxide levels so the scientists hypothesise the if carbon dioxide levels rise with climate change we might expect future plants to have fewer stomata. This counters the increased growth expected due to increased photosynthesis (sun energy + carbon dioxide => oxygen + water) if carbon dioxide levels rise.

Less transpiration means less water in the atmosphere and in turn less rain. All very interconnected and complicated. But read it for yourself.

Image: I'm not going to include a picture of a stomate because they look too rude. Instead, I've included a picture of Sam Podjarski from Opera Australia playing his violin in the Pyramid (part of the Tropical Centre at Sydney's Royal Botanic Garden), in front of a leaf.

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