Senescence, Biology

Senescence

Plants begin their development after seed germination. They grow, flower and finally senesce and die. The period from the start to death is called the longevity or age or life span and this period varies from species to species. For example, some plants, like annuals, complete their life cycles within a few months whereas others live for a few centuries. For example, the life of Juniperus scopulorum is around 3,000 years. The period just before death is called the senescent period.

This may be compared to old age in animals. In this period deterioration occurs because there is a consistent decrease in viability and increase in vulnerability. This phase can be prolonged but cannot be reversed. Senescence may occur very quickly or may be a very slow process. In a plant sometimes the individual organs senesce while the whole plant may remain healthy. In annuals, the whole plant dies; in biennials, the plant dies only after two years, whereas in perennials, year after year the leaves and fruits are shed but the main plant survives.

Posted Date: 1/17/2013 7:51:34 AM | Location : United States







Related Discussions:- Senescence, Assignment Help, Ask Question on Senescence, Get Answer, Expert's Help, Senescence Discussions

Write discussion on Senescence
Your posts are moderated
Related Questions
Eutrophication "Runaway" growth of the aquatic plants which takes place when agricultural fertilizers containing the phosphorus and nitrogen run off into lakes and ponds; also ult

Q. Ecological Evidence of organisms to environment? Ecology is concerned with organisms in relationships to their environment. These relationships may be classified as biotic,

Define Bioactive Substances from Protein Foods? Bioactive substances are derived from living organisms that can be used by humans for a variety of applications. They are consti

Fate of the germ layers In cnidarians and ctenophores, all the cell types develop from either ectoderm or endoderm. Similarly all the tissues and organs in the rest of the ani


Explain Pro-Oxidants Transition metals, particularly those possessing two or more valency states and a suitable oxidation - reduction potential between them (e.g., cobalt, cop

Environmental factors of viscosity and plasticity a) Temperature affects the viscosity of a colloid. Generally, its viscosity decreases as the temperature increases. For e.g.

Explain the effect of Deficiency of Copper in Human? Owing to the remarkable homeostatic mechanisms, copper deficiency in humans is rare. However, copper deficiency has been re

Minerals and reproduction The mechanism of mineral-reproduction interactions is not fully understood becauseĀ  of the complexity of neuro-hormonal dialogue. Some minerals act direc

Define Agar Syringe/Agar Sausage Method? Agar syringe method involves 100 ml syringe, which is filled with agar. A layer of agar is pushed beyond the end of the barrel by means