Plants Could Combat Drought

Chinese scientists have recently reported breakthroughs in developing new types of plants, which could lead to new breeds and improve soil conditions in drought-stricken western regions.

Drought Resistant

Scientists from Lanzhou University reported that they have deciphered the code of a drought-resistant plant, licorice, and hope to create new plant species to green drought-prone western areas of the country.

The plant's molecular marker, which helps it resist extreme drought, has been located, researchers said.

It will be crucial for the cloning of licorice genes, a major step towards the breeding of transgenic plant species resistant to drought.

"Basically, we will not be far from applying the technique to practical uses once the cloning is accomplished," said Wang Genxuan, a professor from Lanzhou University in Northwestern China's Gansu Province. He heads the research team.

The research, done in the State Laboratory for Agricultural Biology in Drought-stricken Areas, found the pores of the licorice plant alternately open and shut when temperatures rises and moisture in the air falls to a specific degree, allowing it to efficiently utilize water to survive.

Experiments at the laboratory suggest the "switch function" of licorice pores can save up to 50 percent of water.

The research also found licorice cells boast a special molecular structure.

Researchers said the discovery will allow the cloning of drought-resistant genes that could be used to breed high-yielding crops to be grown in dry areas.

China's western regions are known for extreme climatic conditions, which has caused plants to develop particular genes that protect them against high and low temperatures, drought or salt. "Using genetic engineering technology to breed new plant species may greatly improve the vegetation cover over vast areas of deserts and bare hills," said Wang, who is also director of the lab.

Latest research in the area suggests that the drought-resistant capacity of plants such as licorice may be controlled by more than one gene, as previously thought, which makes study of their co-functioning more difficult, he said.

The research was initiated four years ago and funded by the Ministry of Education and the Ministry of Science and Technology, according to Wang.

Arsenic I Absorbent

Chinese scientists have also discovered a plant that can efficiently absorb arsenic, a lethal chemical, from the environment and clean up soil polluted with it.

This plant, referred to by local people as Centipede Leaf, was discovered in Central China's Hunan Province and South China's Guangxi Zhuang Autonomous Region by two research fellows, Chen Tongbin and Wei Chaoyang, from the China Institute of Geological Science and Resources.

The plant was identified as belonging to a family of ferns and proved extraordinarily efficient in absorbing arsenic from soil.

A check of chemicals in its leaves suggested an arsenic presence much higher than that of nitrogen and phosphorus, both common in plants.

"This extremely high absorbing capacity ensures the plant can survive highly polluted environments with as much arsenic presence as 3 percent," said Chen Tongbin. "It may have a very bright future if it is used in the rest of the country."

Chen said thousands of square kilometres of land in western China suffers from arsenic pollution, which was caused both naturally and by human activities.

Arsenic has been widely used across the world in chemical products such as pesticides, antiseptics and semiconductors, which poses a direct threat to soil and water.

Human exposure to an arsenic polluted environment can lead to liver cancer, skin cancer, and even to death, said Chen.

The idea of using plants to remove chemical pollutants from the soil was raised in the early 1980s, he said.

Using this approach, chemicals can be recovered for recycling while the soil is being cleaned up.

(China Daily 04/17/2001)

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