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

How the wet beriberi developed rapidly, How the Wet beriberi Developed Rapi...

How the Wet beriberi Developed Rapidly? Oedema is the significant feature of wet beriberi. It may develop rapidly and involve not only the legs but also the face, trunk and ser

Does thermal inversion occur in the winter or in the summer, Does thermal i...

Does thermal inversion occur in the winter or in the summer? Pollutant low altitude thermal inversion happens in the winter. In this period of the year the sun heats the soil l

Cockroach - tracheal system, can you give brief diagram of the tracheal sys...

can you give brief diagram of the tracheal system of cockroach?

Management of ventricular septal defect, Management   In case of  small...

Management   In case of  small defects surgical treatment is not indicated because spontaneous closure may occur before one to two years of  age. Patient  is treated for conges

Explain nutrient requirements during hypertension, Q. Explain nutrient requ...

Q. Explain nutrient requirements during hypertension? In order to meet the above objectives, we need to understand the nutrient requirements during hypertension. Let us start w

False positive st changes, Q. False Positive ST Changes? 1) The slope ...

Q. False Positive ST Changes? 1) The slope of the PQ-segment can help predict the magnitude of the influence of P-wave depolarization and thus help predict which patient wou

Simple precautions to prevent injuries, When resheathing needles, simple pr...

When resheathing needles, simple precautions to prevent injuries are to: 1. use only one hand to scoop the cap 2. hold the sheath with a hemostat (suggested but will require

What are the endocrine functions of the placenta, Q. What are the endocrine...

Q. What are the endocrine functions of the placenta? The placenta has endocrine function since it secretes the hormones estrogen and progesterone that maintain the endometrium

Explain protoderm in primary growth in shoot, Explain Protoderm in primary ...

Explain Protoderm in primary growth in shoot? The protoderm is one of the so-called "primary tissues" because it is formed first during germination and subsequent bud growth an

Explain adverse effects, Explain Adverse Effects Fluconazole is genera...

Explain Adverse Effects Fluconazole is generally well tolerated. Gastrointestinal distress and rash can happen. Stevens-Johnson syndrome, anaphylaxis and hepatic necrosis have

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