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

What is low gradient aortic stenosis, Q. What is Low Gradient Aortic Stenos...

Q. What is Low Gradient Aortic Stenosis? One may come across patients who have severe left ventricular dysfunction and modest gradients across aortic valve. This situation may

Ventilation of tracheal system - diffusion, Ventilation of Tracheal System ...

Ventilation of Tracheal System - Diffusion Gaseous exchange due to diffusion generally takes care of the oxygen needs of most small insects. Similarly fairly large but inactiv

Timber, what is cup shake?

what is cup shake?

How to investigate aortic stenosis by echo cardiography, Q. How to investig...

Q. How to investigate aortic stenosis by Echo Cardiography? 2D Echo cardiogram shows the number of cusps. But presence of raphae and distorted anatomy due to calcification may

Staging of heart failure, In this unit you have learnt that heart failure i...

In this unit you have learnt that heart failure is one of the most common conditions seen and results in a high mortality. It can result from failure of the heart muscle as with co

The transport system in earthworm., The transport system in earthworm ...

The transport system in earthworm The scientific name of earthworm is megascolex. It consists of hearts, blood vessel and blood. There are 8 pairs of hearts in the earthw

Define essentiality of carbon for growth of micro-organism, Define the Esse...

Define the Essentiality of Carbon for the Growth of Microorganisms Carbon is needed for the skeleton of all organic molecules. Microorganisms acquire it either as inorganic car

Chronic mitral regurgitation-mitral regurgitation, Chronic Mitral Regurgita...

Chronic Mitral Regurgitation Chronic mitral regurgitation may have different aetiological factors: 1) Rheumatic 2) Degenerative-myxomatous malformation 3) Infective

What is photoperiod, What is photoperiod? Photoperiod is the daily time...

What is photoperiod? Photoperiod is the daily time period of light exposure of a living being. The photoperiod might be vary according to the period of the year.

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