Senescence, Biology

Assignment Help:

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.


Related Discussions:- Senescence

Explain hepaticae, Hepaticae (Liverworts) The gametophyte is thalloid b...

Hepaticae (Liverworts) The gametophyte is thalloid body or simple stem and leaves, with aquatic or semi-terrestrial habit. Rhizoids are multiceillular. Some examples : Mar

Reed-swamp stage - hydrarch, Reed-Swamp Stage - Hydrarch This stage is...

Reed-Swamp Stage - Hydrarch This stage is also known as amphibious stage, as the plants of the community are rooted but most parts of their shoots remain exposed to air. Speci

Explain vernalisation, Name the state in humans in which the blood choleste...

Name the state in humans in which the blood cholesterol content becomes abnormally high. a) Explain vernalisation. b) Many villagers near Industrial area vary from "blue bab

Nonsurgical retreatment will be the preferred choice, Nonsurgical retreatme...

Nonsurgical retreatment will be the preferred choice -Less invasive .. not cause problem to the pt. -Less traumatic postoperative .. most probably no post operative pain

Explain what is light microscope - microscopy, Explain what is Light Micros...

Explain what is Light Microscope - Microscopy Modern light microscopes are compound microscopes. Here the magnified image formed by the objective lens is further enlarged by on

Pachytene, Pachytene: The pairing of homologous chromosomes is comp...

Pachytene: The pairing of homologous chromosomes is completed. Chromosomes become more and more thick. Each bivalent has four chromatids , which wrap around each o

The genetic code within a dna molecule, How is a genetic trait determined b...

How is a genetic trait determined by the genetic code within a DNA molecule? A DNA molecule has 4 dissimilar bases, either CGTA. Any specific combination of these things forms

What is an atom referred to in ionic bonds, What is the positive atom refer...

What is the positive atom referred to in ionic bonds and write a monovalent and divalent example.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd