About fifty years ago, plant physiologists set out to grow roots by themselves in solutions in laboratory flasks. The scientists found that the nutrition of isolated roots was quite simple. They required sugar and the usual minerals and vitamins. However, they did not require organic nitrogen compounds. These roots got along fine on mineral inorganic nitrogen. Roots are capable of making their own proteins and other organic compounds. These activities by roots require energy, of course. The process of respiration uses sugar to make the high energy compound ATP, which drives the biochemical reactions. Respiration also requires oxygen. Highly active roots require a good deal of oxygen. The study of isolated roots has provided an understanding of the relationship between shoots and roots in intact plants. The leaves of the shoots provide the roots with sugar and vitamins, and the roots provide the shoots with water and minerals. In addition, roots can provide the shoots with organic
A. The relationship between a plant’s roots and its shoots.
B. What can be learned by growing roots in isolation.
C. How plants can be grown without roots.
D. What elements are necessary for the growth of plants.
What will the world be like in fifty years
This week some top scientists, including Nobel Prize winners, gave their vision of how the world will look in 2056, from gas-powered cars to extraordinary health advances. John Ingham reports on what the world’s finest minds believe our futures will be.
For those of us lucky enough to live that long,2056 will be a world of almost perpetual youth, where obesity is a remote memory and robots become our companions.
We will be rubbing shoulders with aliens and colonising outer space. Better still, our descendants might at last live in a world at peace with itself.
The prediction is that we will have found a source of inexhaustible, safe, green energy, and that science will have killed off religion. If they are right we will have removed two of the main causes of war--our dependence on oii and religious prejudice.
Will we really, as today’s scientists claim, be able to live
A. human organs can be manufactured like appliances
B. people will be as strong and dynamic as supermen
C. human nerves can be replaced by optic fibers
D. lost fingers and limbs will be able to regrow
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