Kids Research Express

Gibberellin, one of the groups of hormones that influence the growth of plants. They are chemical substances that occur naturally in many plants and regulate various important functions, such as the elongation of flowering stems, the creation of proteins, and the germination of some plant seeds. Unlike auxins , which are plant hormones that form in the plant’s top shoots and flow downward to affect the growth of plant parts, gibberellins form in the seeds, young leaves, and plant roots before flowing upward into the stem. Gibberellins were discovered in 1926 by Japanese scientists investigating foolish-seedling disease in rice. This disease caused rice shoots to grow extremely long without corresponding root growth. As a result, the seedlings did not flower and usually died before maturity. Foolish-seedling disease was traced to the fungus Gibberella fujikuroi, which produces substances now known as gibberellins. More than 50 different gibberellins have been isolated and identified; th

Auxin, any of a group of plant hormones, substances naturally produced in actively growing parts of plants that regulate many aspects of plant growth and development. These substances affect the growth of the stem tip, leaves, and roots, and the development of side branches and fruit. Auxins affect the growth of these plant parts by stimulating certain cells to elongate, or lengthen, and by inhibiting the growth of other cells, depending on the amount and distribution of auxin in the plant tissue. The effect of auxin on plant cells is important in controlling plant functions called tropisms. A tropism is a plant’s response to external stimuli that causes a change in the direction of the plant’s growth, such as bending, turning, or curving. When an indoor plant is placed in a sunlit window, the plant appears to bend or grow toward the sun. This response to the stimulus of light is called phototropism. It is believed that light destroys auxin where it strikes the stem, causing an imbalan

Digitalis, genus of plants of the figwort family. One species introduced from Europe, the common foxglove, is a self-seeding biennial or perennial herb, widely grown in gardens and naturalized along roadsides and in meadows or logged-off areas, especially in the western United States. The naturalized plant bears a showy, terminal cluster of hanging, tubular, spotted, purple flowers. Cultivated varieties are of various colors and markings. The erect stems are about 91 cm (about 36 in) tall with numerous large, thick leaves at the base. Digitalis, a drug prepared from digitalin, a glycoside obtained from the common foxglove, is used in medicine. With techniques of modern pharmacology, about a dozen steroid glycosides have been isolated from the leaves. The best known of these exert a twofold action on the heart that results in a more effective heartbeat. These medicines strengthen the force of contraction and, at the same time, slow the beat so that the period of relaxation between be

Classification of Insectivorous Plants Plants that obtain at least some of their nutrition by capturing and digesting prey are called insectivorous, or carnivorous, plants. Such plants have adaptations that allow them to attract, catch, and break down or digest prey once it is caught. Estimates of the number of species of carnivorous plants number from 450 to more than 600. Generally, these plants are classified into genera based upon the mechanism they have for trapping and capturing their prey. The major genera of these plants are listed below. Common name Scientific name Trapping mechanism bladderwort Utricularia vulgaris active trap; shows rapid motion during capture butterwort Pinguicula vulgaris semiactive trap; two-stage trap in which prey is initially caught in sticky fluid California pitcher plant Darlingtonia californica passive trap; attracts prey with nectar and then drowns prey in fluid contained within plant flypaper plant Byblis liniflora passiv

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

Saffron, bright-yellow flavoring and coloring material, consisting of the dried stigmas and style branches of the saffron crocus, the bulbs of which were introduced to Europe from Asia Minor.

Biennial, any plant that normally requires two years for its life cycle. Biennials store food in the first season of their growth, flower and bear fruit in the second season, and then die. Familiar examples are foxglove, hollyhock, and pansy. Many cultivated vegetables are biennials, for example, carrots, turnips, parsnips, parsley, and celery. Biennials often become annuals when early sowing or warm weather causes the earlier development of a flowering stem. Less hardy varieties are often routinely treated as annuals.