Pear

-

Pear, name for a fruit tree of the genus Pyrus of the family Rosaceae (rose family) and for its fruit, a pome. The common pear (P. communis) is one of the earliest cultivated of fruit trees, both in its native W Asia and in Europe. Most of the pear strains grown for their sweet and juicy fruit are varieties of P. communis or of its hybrids with other species of Pyrus—usually P. pyrifolia, known as the Japanese, Chinese, or sand pear and indigenous to China. The main use of the sand pear today is as a rootstock in pear orchards; the related quince is used for the same purpose. Pear strains with fruit of really good eating quality were not developed until the 18th and 19th cent. in N Europe, whence almost all the present successful varieties (e.g., the Bartlett and Seckel) grown in the United States (chiefly on the Pacific coast and in the Great Lakes area) were directly imported. European production is far greater—especially in Germany, France, and Switzerland, where much of the crop is used for making pear cider (perry). Pears are also cultivated on a large scale in Japan, Turkey, Argentina, and Australia. They are usually sold fresh or canned; some are dried. Several varieties of the common pear and of other species—e.g., the small, white-foliaged snow pear (P. nivalis)—are cultivated as ornamentals, and pear wood, hard and dense, is used to a limited extent in cabinetmaking. The pear tree and its fruit are similar to the closely related apple (considered by some botanists to be of the same genus) in characteristics and in method of cultivation, but the tree is somewhat less hardy and the fruit more perishable. Pear or fire blight is the tree's most serious disease; it is also attacked by several insect pests. Pears are classified in the division Magnoliophyta, class Magnoliopsida, order Rosales, family Rosaceae.

Comments

Post a Comment

Popular posts from this blog

Plant: Cell Structure And Function

-
Image
Plant Cell Plant cells contain a variety of membrane-bound structures called organelles. These include a nucleus that carries genetic material; mitochondria that generate energy; ribosomes and rough endoplasmic reticulum that manufacture proteins; smooth endoplasmic reticulum that manufactures lipids used for making membranes and storing energy; and a thin lipid membrane that surrounds the cell. Plant cells also contain chloroplasts that capture energy from sunlight and a single fluid-filled vacuole that stores compounds and helps in plant growth. Plant cells are surrounded by a rigid cell wall that protects the cell and maintains its shape. The tremendous variety of plant species is, in part, a reflection of the many distinct cell types that make up individual plants. Fundamental similarities exist among all these cell types, however, and these similarities indicate the common origin and the interrelationships of the different plant species. Each individual plant cell is at
Read more

Insectivorous Plants

-
Image
Insectivorous Plants, also carnivorous plants, plants that gain some of their nutrition from animals, especially insects, captured by the plants themselves. Most occur in bogs where the soil is acid and poor in available nitrogen; capturing insects is one way of getting nitrogenous compounds without manufacturing them. At the same time, the green leaves of these plants manufacture carbohydrates. The trapping mechanism of insectivorous plants is relatively small. Therefore, prey is almost inevitably limited to small insects. Insectivorous plants are diverse and represent members of three orders of dicots : Nepenthales, Scrophulariales, and Rosales. A majority are in the Nepenthales, including the pitcher plant , sundews and the Venus's-flytrap, and East Indian pitcher plants. Others include the bladderworts, butterworts, and the Australian pitcher plant. Discussed below are the sundews and bladderworts. Certain species of fungus are known to be carnivorous as well. Venus’s-Flytrap
Read more

Parts of a flower

-
Image
All flowers share several basic features. Sepals, protective coverings that are closed over the bud before it blooms, are the outermost flower parts. One step inward lie the petals, which serve to attract pollinators using both coloration and scent-producing glands. Inside the petals are the flower's sexual organs, the stamens and pistil. Each stamen, the pollen producing part of the flower, includes an anther and a filament. At the center of the flower is the pistil, composed of a stigma, a style, and an ovary. Within the ovary is a small cavity that contains the ovule, an egg-shaped structure that, when fertilized, eventually becomes a seed. Flowers typically are composed of four parts, or whorls, arranged in concentric rings attached to the tip of the stem. From innermost to outermost, these whorls are the (1) pistil, (2) stamens, (3) petals, and (4) sepals. Pistil The innermost whorl, located in the center of the flower, is the female reproductive structure, or pistil. Often va
Read more