My Science School

 

 

           Some plants capture insects and other tiny animals and use them as food. They do not devour their prey by chewing but decompose them in a mixture of enzymes. The pitcher plant attracts an insect to its large showy leaf by means of sweet-smelling nectar. The leaf has a treacherous lip which precipitates the unwary victim into a deep hollow pitcher full of digestive “broth”, which soon decomposes its body. Other plants, like the Venus’s flytrap, snap their leaves shut on their prey as it prowls about the trigger hairs glistening with drops of nectar. The sundews secrete a sticky fluid.

A loofah is a fibrous, cylinder-shaped vegetable product often used in bathrooms as a kind of rough sponge or gentle brush. It is the dries interior of the fruit of a plant known to botanists as Luffa aegyptiaca. Less dignified, though more descriptive, names for this tropical climbing or trailing herb are dishcloth gourd and vegetable gourd.

     The Luffa belongs to the great gourd family of plants, and its 800 relations include the cucumber, the melon and the pumpkin. In spite of having an unpleasant smell, the Luffa is cultivated in Egypt (hence the second part of its Latin name) and in Arabia, India and china. The yellow-flowered climbers can sometimes be seen adorning the trunks of palm trees. Besides being used to make loofahs, the luffa’s fruit is eaten in curry.

     The development of man-made materials has led to a decline in the loofah’s popularity, but many people still use its slightly abrasive qualities to stimulate the skin.

      The breadfruit tree is found in the South Pacific Islands and, to a lesser, degree, in other parts of the tropics. It is an extremely handsome tree, growing up to 60 feet high. The oval leaves are a pleasant, glossy green and quite large.

      There are two distinct forms of breadfruit, one seedless and the other containing many seeds which, when boiled or roasted, taste much like chestnuts.

   The breadfruit, which contains a considerable amount of starch, is not really a fruit in the popular sense and is rarely eaten raw. It can be boiled or baked, served with salt, butter or syrup, and even sliced and fried like potatoes.

     Yews have long been associated with religious worship. So it is likely that churches were originally built near the sacred trees rather than the other way round.

     These trees live longer than any other species in Europe and can grow to an enormous size. Many are thought to be well over 1,000years old. Yews were revered by the druids of ancient Britain, France and Irelands and no doubt early Christian missionaries preached in the shelter of the trees before their first churches were built. Hywel Dda Howell the Good a Welsh king, who reigned in the 10th century, set a special value on “consecrated yews”.

   Some yews are even older than the ancient churches beside them, suggesting that the church was built on a spot already devoted to worship. The association continued, and it became traditional for yews to be planted in church yards.

    Also the great age to which yews live caused them to be regarded as a symbol of immortality and, therefore, associated with death, as man only becomes immortal after he dies.

The sweet scent of flowers is designed to attract insects who seek food in the shape of pollen and the fragrant-smelling nectar. This nectar is a solution of sugars produced in little sacs called nectarines at the base of the flower petal.

     The insects have a part in the process of fertilization. Almost all plants perpetuate themselves by means of sexual reproduction, during which a male reproductive cell or sperm fuses with female reproductive cell or egg.

     When bees or other insects visit flowers in search of the sweet-smelling nectar, parts of their hairy bodies become dusted with pollen which contains the male reproductive cells. This rubs off on the flower’s carpels which contain the egg or ovule.

Insects seem to be strongly attracted by sweet scents. In fact, some flowers, such as the meadow sweet, are so highly scented that insects are attracted to them although they have no nectar to offer. Most insect-pollinated flowers have evolved wonderful devices for guiding the movements of that pollen is dusted over the insect’s body

Reindeer moss is a species of lichen so called because it is the staple winter food of reindeer (and caribou) in Arctic and Sub-Arctic regions. The animals reach the plant by scraping away the snow with their feet. But Plant growth in those cold northern lands is so slow that the lichen can take more than 30 years to recover after the reindeer have grazed. These domesticated herds therefore have to travel long distance in search of food, and the Laplanders of northern Scandinavia, who depend on the animals for their livelihood, must travel with them.

      Fortunately, reindeer moss is especially abundant in Lapland, although it also grows extensively in much of northern Europe, the tundra (or treeless plains) of Siberia and the barren expanses of Arctic America.

     During the short summer the reindeer are able to feed on herbage and shoots then accessible in the valleys. These versatile animals provide the Laplanders with meat, milk, cheese and the raw materials for clothing, shoes and tents. They are also a means of transport.

     Reindeer moss is sometimes eaten by human beings, after being powdered and mixed with other food. But it leaves a slightly burning sensation on the human palate. This bluish-grey plant grows erect in tufts, and is remarkable for its many branches, which, strangely, resemble a deer’s antlers.