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

Classification of anaemia based on etiology, Classification of Anaemias Bas...

Classification of Anaemias Based on Etiology   Anaemia  can be classified  as   Impaired Production of Red Blood Cells and Hemoglobin: This can be due to nutritional  def

Water, Water Water is the most important constituent of all living tis...

Water Water is the most important constituent of all living tissue. It forms up to 95% of the fresh weight of some animals. We all know that water is lost through sweat, excre

Life cycle of sporozoans, Life cycle of sporozoans The complex life cy...

Life cycle of sporozoans The complex life cycle of sporozoans typically involves an asexual and a sexual phase. Sporozoans are haploid except for the zygote. The zygote underg

What is isonietric exercise in dynamic auscultation, What is Isonietric Exe...

What is Isonietric Exercise in dynamic auscultation ? Can be carried out by doing handgrip exercise which is sustained over 20-30 second. It results in transient increase in SV

Illustrate the advantages of ridgemapping, Advantages of Ridgemapping T...

Advantages of Ridgemapping This procedure is a good indicator of the available bone width and helps in understanding the angulation of the available bone to the eventual prosth

Diffrence between gymnosperms and bryophytes, Q. How different are gymnospe...

Q. How different are gymnosperms from pteridophytes and bryophytes? Gymnosperms are not cryptogamic as pteridophytes and bryophytes are. They are phanerogamic and so they form

Define and compare bone modeling and remodeling, Define and compare bone mo...

Define and compare bone modeling and remodeling Bone modeling is a surface-specific activity (apposition or resorption) that produces a net change in the sie and/or shape of a

Explain coronaw artery disease, Explain CORONAW ARTERY DISEASE (CAD)? A...

Explain CORONAW ARTERY DISEASE (CAD)? As far as CAD is concerned the people of South Asian region are at a very disadvantageous position. The term 'South Asians' includes perso

Depth and currents, Depth and Currents Depth The sea is v...

Depth and Currents Depth The sea is very deep varying in different regions. Generally life extends to all depths but is confined more to the continental shelf and

Sepsis, Dietary management of sepsis without MODS

Dietary management of sepsis without MODS

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