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
Q. Why can the amphibian circulation be classified as incomplete and double? The amphibian circulation is double because it is composed of pulmonary and systemic circulations r

Pathophysiology   If  the ductus arteriosus does not close after birth, the higher pressure in the aorta than in the pulmonary artery causes the blood to flow from the aorta, t

THEORIES TO EXPLAIN FINE STRUCTURE OF CHROMOSOME (1 ) Multistranded theory Steffenson 1959 - each chromosome composed of two chromatids (Half Chromosome) and each chromat

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Nutritive value of crop residues Nutritive value is generally determined by feed composition, intake and utilization  efficiency of digested matter. Thus, the value of a feed

Hypomagnesaemic tetany (grass tetany, grass staggers, lactation tetany) Hypomagnesaemic tetany is a multifactorial complex metabolic disorder, which is  characterized by reduct

Pre-surgical Prosthodontics Radiographic investigation: The radiologic investigations are critical to evaluate the bone quality and bone quantity. 1. Panoramic Radiograph

The nucleolus is a small and optically dense region in the interior of the cell nucleus. It is made of ribosomic RNA (rRNA) and proteins. Single nucleus can have one or more nucleo

Q. Is there an exchange of cells between the mother and the fetus through the placenta? Under usual conditions there is no passage of cells across the placenta during gestation

PKU is a recessive disorder. Suppose two people who were heterozygous for PKU married and had a child. What is the probability that the child will have PKU?