1. While
everybody enjoys fresh cut flowers around their house, few people know how to
keep them for as long as possible. This may be done by keeping in mind a few
simple facts. 2. An important thing to remember about cut
flowers is that they are sensitive to temperature. For example, studies have
shown that cut carnations(康乃馨) retain their freshness eight times longer when
kept at 12℃ than when kept at 26℃. Keeping freshly harvested flowers at the
right temperatures is probably the most important aspect of flower
care. 3. Flowers are not intended by nature to live very long.
Their biological purpose is simply to attract birds or insects, such as bees,
for pollination(授粉). After that, they quickly dry up and die. The process by
which flowers consume oxygen and produce carbon dioxide(二氧化碳), called
respiration(呼吸), generates the energy the flower needs to give the flower its
shape and color. The making of seeds also depends on this energy. While all
living things respire, flowers have a high level of respiration. A result of all
this respiration is heat, and for flowers the level of heat relative to the mass
of the flower is very high. Respiration also brings about the eventual death of
the flower. Thus the greater the level of respiration, the sooner the flower
dies. 4. How, then, to control the rate at which flowers die?
By controlling respiration. How is respiration controlled? By controlling
temperature. We know that respiration produces heat, but the reverse is also
true. Thus by maintaining low temperatures, respiration is reduced and the cut
flower will age more slowly. 5. Another vital factor in keeping
cut flowers is the quality of the water in which they are placed. Flowers find
it difficult to "drink" water that is dirty or otherwise polluted. Even when
water looks and smells clean, it almost certainly contains harmful substances
that can endanger the flowers. To rid the water of these unwanted substances,
household chlorine bleach(含氯漂白剂) can be used in small quantities. It is
recommended that 15 drops of chlorine bleach (at 4% solution) be added to each
litre of water. The water and solution should also be replaced each day.
填空题
Paragraph 2 ______
A. Control of Respiration
B. Beauty of Fresh Cut Flowers
C. Role of Respiration
D. Most Important Aspect of Flower Care
E. Need for Clean Water
F. Ways of Stopping Respiration
填空题
Paragraph 3 ______
填空题
Paragraph 4 ______
填空题
Paragraph 5 ______
填空题
A few simple facts will help you keep cut flowers ______.
A. by keeping its original shape and color
B. in the life of cut flowers
C. to produce carbon dioxide
D. for as long as possible
E. by controlling temperature
F. to replace the water and solution every day
填空题
Respiration plays a key role ______.
填空题
The aging of cut flowers can be slowed down ______.
填空题
Another important way to prolong the life of cut flowers is ______.