Earth and Sky:Sunscreened Plants 遮光植物

Sunscreened Plants 遮光植物

A NASA researcher is finding that alfalfa plants grow more poorly when exposed to UVB -- ultraviolet B radiation from the sun. Learn more about sunscreened plants -- today on Earth and Sky.

JB: This is Earth and Sky. Earth's ozone¹ layer protects us from the sun's ultraviolet -- or UV, radiation. Ozone depletion² has been blamed for an increase in skin cancers in human beings.

DB: And this radiation seems to have a negative effect on plants as well. Jay Skiles is a scientist at NASA's Ames Research Center in Mountain View, California.

Jay Skiles: ... and what we found is that the ozone depletion is not only in the southern hemisphere over the poles but we're actually getting increased ultraviolet light here, at about 38 degrees north latittude ...

JB: For the past six years, Skiles has been growing alfalfa in three ways -- in the open air -- and under two kinds of filters. One set of filters block harmful UVB, or ultraviolet B radiation. The other filters let pass all light from the sun. Filtering UVB more or less simulates conditions that existed under an intact ozone shield -- before ozone depletion.

Jay Skiles: And we're finding that plants that are grown without UV ... are actually doing better -- they're producing more above-ground biomass. Their morphology is better, they're more vigorous, more chlorophyll . . . and they actually survive longer.

DB: . . . more evidence that Earth's ozone layer must remain protected and intact. For more, come to today's show at earthsky.org. Special thanks today to NASA's Earth Science Enterprise. We're Block and Byrd for Earth and Sky.

1 ozone   

n.臭氧，新鲜空气

参考例句：

• The ozone layer is a protective layer around the planet Earth.臭氧层是地球的保护层。
• The capacity of ozone can adjust according of requirement.臭氧的产量可根据需要或调节。

2 depletion   

n.耗尽，枯竭

参考例句：

• Increased consumption of water has led to rapid depletion of groundwater reserves.用水量的增加导致了地下水贮备迅速枯竭。
• Farmers should rotate crops every season to prevent depletion of the soil.农夫每季应该要轮耕，以免耗尽土壤。