PS COLUMN ARCHIVE

April 30, 2008

Power of plant and its wonder

Cherry blossom front is reported as moving up in Hokkaido. It passed Tokyo on March 21, one week earlier than average year, to have made it full bloom already at the end of March. Many of you, I suppose, must have enjoyed viewing cherries in a little bit chilly weather. As is cherry viewing time over with falling flower petals, it’s turned to cherry leaves season with leafy row of cherry trees. Roadside tree leaves are greening up day by day, of which fast growing surprises us indeed.

For this growth of greens, young leaves must be absorbing large volume of carbon dioxide gas from air. Plants produce starch from carbon dioxide gas contained in air. We really have to give those plants credit for producing oxygen by absorbing carbon dioxide that is said to cause global warming. The reason of a slight decrease in concentration of carbon dioxide, which is totally increasing throughout every year, at this time of a year is said to be owing to carbon dioxide assimilation of the plants.

In our school days, we learned of this plant function as carbon dioxide assimilation but now they seem to call it “photo synthesis”. It is understandable of their calling it so, because the plants do not only absorb carbon dioxide but also need sunlight for their botanical function. I regret a little bit, however, that it is rather hard to imagine, from the way to call it photo synthesis, of their actually absorbing carbon dioxide from air.

And now, we learned of photo synthesis even at elementary school. I think many of you must have experience of chemical experiment at science classroom; when you extract chlorophyll and others by boiling sun-lighted plant leaves by alcohol and dunk them in iodine solution, then sun-lighted parts of the leaves turn into purple color. This is to verify the producing of starch in the leaves detected by iodine solution.

Even learned at elementary school, however, mechanism of photo synthesis is very complicated. Among the scientists who tried to find out this mechanism, as many as five of them were awarded the Nobel Prize. Each one of them clarified mechanical function in a certain process of photo synthesis, nevertheless much is still remained mysterious. Therefore, mechanism of photo synthesis is still unable to be artificially reproduced.

If some material is to be invented for artificial photo synthesis, then we may have an instrument to artificially turn carbon dioxide in air to oxygen. If realized, I think serious problems of global warming and energy shortage will move much closer to resolution. What do you think? Looking at fast growing street leaves different day by day might have made me too much dreamful. On the other hand, I believe there must be scientists who are absorbed in studying this problem with the same dream as mine. All the above written is my dream and expectation so much amazed by greenery season brought by the wonders of nature power.

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