EVENING PRIMROSE: A UNIQUE BOTANICAL SPECIMEN
In its natural state, the evening primrose is a wild flower. But it is only in the last decade or so that agronomists have turned this wild, untamed flower into a crop.Most crops have been in existence for centuries. Farmers have had plenty of time to learn about their cultivation. The evening primrose, however, is a brand new crop and has presented an enormous challenge to agronomists who are trying to master its cultivation in a fraction of the time devoted to other crops.Grown from seed, the evening primrose plant produces a rosette of leaves close to the ground in the first year. The following season the plant shoots up to produce a main stem that can be 5 or 6ft tall (almost 2m) bearing the attractive yellow flowers, and then the seed pods in late summer and early autumn.Botanists first became interested in the evening primrose plant at the beginning of the century when it was thought it was breaking the laws of inheritance discovered a few years earlier by Mendel.In ordinary species, if two plants are cross-pollinated, the first generation of offspring is identical to one another. But in the second generation they form a mixture of two types intermediate between the two parents. In further generations new variants continue to be produced.The evening primrose, however, does something very different. If two plants are crossed, the first generation usually turns up as a mixture of two types which don’t resemble either of the two parents or each other. In the next generation, the two groups do not split up into a mixture. Instead, the plants breed true. This is because the plants have an unusual chromosome which can repeat itself for many generations without any variation.From a distance, a cluster of plants might look the same. But at a closer look one sees there are some subtle variations between one type and another. The size of the flowers can vary from Vain to 5in (1 to 13cm), and the pigment may differ in each plant. Although most evening primroses are yellow, some have a mauve hue, and there are many variations in colour in each part of the plant. There are huge differences in plant size, too. Some grow no higher than dandelions, while others can shoot up to more than 8ft (2.4m) high.Some evening primrose plants need bees or moths for pollination; others are self-pollinating. The variations provide great challenges for plant breeders aiming to breed the evening primrose for its oil yield.
*3/60/5*
BIO-DIVERSITY: HABITAT AND REGIONS OF MAXIMUM DIVERSITY
(a) ABROAD
The tropical forests, specially, rain forests are regarded as richest in biodiversity. Two third of world’s flowering plants area is tropical which emphasizes the great importance of plant conservation in the tropics. Many economically important families are restricted to the tropics, such as, Annonac-eae, Lauraceae, Moraceae, Dipterocarpaceae, Ebenaceae, Meliaceae, Gramineae and Leguminosae are most important domesticated families followed by Cruciferae, Rosaceae, Umbelliferae, Solanaceae and Labiatae. Other domesticated families are Chenopodiaceae, Araceae, Cucurbitaceae and Compositae.
High species diversity in the tropical forest may be because of constancy of the environment. It may also be because of the result of interaction between climate, organisms, topography rocks, time and heredity in the tropics which is the ideal place for such interaction. Certain extra-terrestrial factors-mass extinction, competitions,competitive exclusion and other biotic interactions also play a role in the evolution of biological diversity. All such conditions for evolutions are considered as optimal and for extinctions fewer.
(b) INDIA
India has a rich diversity with varied flora and fauna, consisting of 67,000 species of insects followed by 15,000 species of flowering plants, 6500 vertebrates, 4000 molluscs, 2000 fishes, 1200 birds, 450 reptiles, 400 mammals and 150 amphibians.
The western ghats in peninsular India, which extend in the southern states are also considered as a treasure house of species diversity. Out of 15,000 species of flowering plants so far identified in India about 5,000 species occurs on the western Ghats of Kerala and as many as 235 species are endemic to this region. Similarly, it is estimated that almost 1/3 of the animal varieties found in India have taken refuge in western Ghats of Kerala.*15\218\2*
Simple experiments will tell you that there are different taste zones on the tongue. If the tip of the tongue is dipped in honey water, the sensation of sweetness is immediately apparent. A little further back on the periphery of the tongue the taste of salt is registered and even further back, also on the periphery, sourness is sensed, while zones registering bitterness are found across the! posterior section. The central part of the tongue is a neutral area, as it does not register any sensation of taste.
It is noteworthy that the tongue is more accurate and reliable as a test organ than many chemical reactions. For this reason a winej merchant, or a tea, coffee or olive oil processing firm will pay more attention to their experienced ‘tasters’ than to the analysts in a chemical laboratory.
Imagine what life would be like without the 3,000 taste buds on our tongues. What would encourage us to eat and drink if there were no pleasure in it? If you have ever had to force yourself to eat without feeling hungry you can well understand the difference. We would also lose our incentive to prepare delicious meals for our families if there were no smile of approval and enjoyment on \ the faces of the happy eaters. Despite its small size, the tongue is endowed with many important functions, providing much satisfac- j tion and pleasure.
*109/28/1*
FDA Approved Prescription Drugs.
Nerve cells which register the sensation of taste and transmit it to the brain are arranged in a bulb-like manner. The nerve ends may be compared to the roots, while the layers of the bulb represent the reaction controls, with built-in amplifiers. To complete the illustration, in the place of the bulb’s top, there are very fine hairlike nerves that register the taste sensation.
These nerve bulbs are called taste buds, because scientists compared them to the literal buds. An adult has about 3,000 of them. But did you know that we humans probably have fewer sensations of taste when eating our food than, for example, antelopes, which have about fifteen times as many taste buds as a human? If we had as many as these animals it would be much easier for us to differentiate between healthy nourishing food and that which is harmful. Thus animals are more capable than humans in distinguishing what is good for them and what is not.
*108/28/1*
Buy prescriptions, discount drugstore