| |
Unique Home Furniture, Home Decorating and Home Decoration Store
Plant Growth Regulation: The synthesis of dormin (abscisin II), known to play a major role in controlling the dormancy of buds, tubers, and seeds, provided a significant advance in 1967 in the study of plant growth regulation. In an analysis of the inhibiting mechanism in Lemna minor (duckweed), concentrations of one part per million of this synthetic compound inhibited growth by about 95%. DNA synthesis appeared to be suppressed, and the breaking of the dormancy was thought to be caused by reactivation of the enzyme DNA-polymerase by a growth hormone.
It is the gardener's task to make use of the weather as much as possible. Temperature directly influences the rate of plant growth. The fastest growth will take place at the higher temperature limits of an individual plant's tolerance. A plant classified as tender will not endure temperatures below 32°F (0°C). A half-hardy plant can stand a few degrees of frost, but not a cold winter. By contrast, a hardy plant can tolerate considerable cold. Naturally, the degree of hardiness varies from plant to plant. How well a plant grows in an area depends largely on its native climate and on how easily it can adapt to its new environment.
The second revolutionary advance in developmental plant biology was one made by botanists themselves. It was the discovery of several new plant hormones, substances which regulate the growth and development of plants. For almost 30 years after its discovery as a plant hormone in 1926, auxin had been regarded as the substance that could account for nearly all the phenomena of plant growth and development in which hormone action was involved.
|
|
|
 |
Child-Education-Usa.com |
|
 |
 |
|
Menu |
|
|
| |
| |
|
|
| |
|
