Why leaves change colour in autumn

Monday, October 25, 2010

LONDON - A scientist has come up with a new theory for why leaves change their colour and then drop from trees in autumn.

Professor Brian Ford, writer and broadcaster, believes leaf drop occurs in order to excrete waste products from the tree.

The president of the Cambridge Society for the Application of Research said, “We have long understood the importance of the leaf as the organ of energy capture, through photosynthesis, and of homeostasis, via transpiration.”

But the leaf is also an excretophore a means of consigning unwanted wastes to the void. This is why all plants drop leaves.

He found that, shortly before they are shed, levels of potentially harmful components such as tannins and oxalates in leaves increase.

“The levels of heavy metals in abscised leaves are also raised, and they are clearly there to be excreted rather than stored,” The Telegraph quoted Ford as saying.

He argued that leaves do not simply die when plants run low on water, as plants, which live in water, such as water lilies, also shed leaves.

“In autumnal landscapes, when plants leaves turn red and brown and are suddenly shed it is important to bear in mind what is happening. The plants are having their annual, well, excretion,” Ford said.

“It does, though, mean that the colouration of leaves in autumn will never seem quite the same again,” he added. (ANI)

Filed under: Science and Technology

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