Description: This is
a VOA Special English Agriculture Report.
See text below
Text:
Scientists have discovered more details about how
plants use water. Their findings could help to
engineer plants that grow better and more
effectively in conditions with higher levels of
carbon dioxide.
Plants naturally take in carbon dioxide they need
for photosynthesis, the process of changing light
energy to chemical energy. The carbon dioxide enters
the plants through tiny holes or pores on the
surface of leaves.
However, each time a plant takes in one molecule of
carbon dioxide gas, it loses hundreds of water
molecules.
Scientists say plants lose ninety-five percent of
the water they take in through these pores. Some
plants pores can tighten to save water during
conditions of high carbon dioxide. Other plants are
not able to do this as well. Now, scientists know
how these tiny pores tighten in plants.
Julian Schroeder is a professor of biology at the
University of California, San Diego. Mister
Schroeder says that carbon dioxide levels in the
atmosphere are much higher now than they were in the
past.
However, he says, many plants are not closing their
pores in order to hold in more water.
He and his team have identified proteins that
control the tightening of a plant's pores. The
proteins are enzymes called carbonic anhydrases. The
findings were published in the journal Nature Cell
Biology.
Mister Schroeder believes the enzymes could be
changed in some plants to increase their ability to
store water.
The researchers added carbonic anhydrase genes to
plants that do not react to higher levels of carbon
dioxide. They observed that for every molecule of
carbon dioxide taken in by the plants, they lost
forty-four percent less water.
The scientists say the photosynthesis process
continued normally in these plants. They say this
suggests that changing plants to save more water
will not affect plant growth.
This method might be used to help engineer food
crops that are resistant to extremely dry
conditions.
The discovery could help farmers meet a growing
demand for food as water supplies decrease.
However, the scientists say more research is needed.
And thats the VOA Special English Agriculture
report. For transcripts, MP3s and podcasts of our
reports, visit us on the Web at
voaspecialenglish.com.
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Hi. I
personally reviewed this video and found it appropriate for
the news section of English Global Group. This
is a Voice of America video which covers an interesting
topic in Special English. I would appreciate some feedback from both
students and teachers about this video. You can comment in
the window below using any of a number of different services
including Facebook, Yahoo, AOL, and Hotmail.
