senescence and abscission pdf

1. What is senescence and abscission?
2. What is meant by abscission?
3. What is abscission in plants?
4. What is the reason of senescence leaf?
5. What happens during senescence?
6. Which hormone is responsible for senescence?
7. What is the role of auxin in abscission?
8. What is meant by abscission Class 11?
9. Which hormone is a gas?
10. What harm does abscission cause to plant?
11. Which hormone promotes the abscission of leaves and fruits?

What is senescence and abscission?

Abscission refers to the normal separation of a senescent plant part or organ, e.g. old leaves or ripe fruits. It occurs to shed or separate the unnecessary plant parts or organs. For instance, shedding of old leaves at the base of the petiole which usually occurs during autumn. ... It is not associated with aging.

What is meant by abscission?

Abscission (from Latin ab, "away", and scindere, "to cut'") is the shedding of various parts of an organism, such as a plant dropping a leaf, fruit, flower, or seed. ... In cell biology, abscission refers to the separation of two daughter cells at the completion of cytokinesis.

What is abscission in plants?

Abscission, from the Latin words ab (away) and sciendere (to cut), is a tightly controlled cellular progression that occurs at given developmental stages during the lifespan of a plant and ensures that plants can shed organs when they are no longer required – such as flowers after pollination or senescent leaves in the ...

What is the reason of senescence leaf?

The common feature of age-induced and stress-induced leaf senescence is chloroplast breakdown, and the authors report that many STAYGREEN (SGR) genes have been shown to play significant roles in regulating chlorophyll breakdown under 'natural' and both abiotic and biotic stress-induced senescence.

What happens during senescence?

Cellular senescence is an essentially irreversible growth arrest that occurs in response to various cellular stressors, such as telomere erosion, DNA damage, oxidative stress, and oncogenic activation, and it is thought to be an antitumor mechanism.

Which hormone is responsible for senescence?

Cytokinin and ethylene have the most extensively documented roles in delaying or inducing leaf-senescence, respectively. Hormones that were reported to delay senescence are giberellic acid, auxin and cytokinin, i.e. hormones that promote growth.

What is the role of auxin in abscission?

Auxin also plays a role in the abscission of leaves and fruits. Young leaves and fruits produce auxin and so long as they do so, they remain attached to the stem. When the level of auxin declines, a special layer of cells — the abscission layer — forms at the base of the petiole or fruit stalk.

What is meant by abscission Class 11?

Abscission is the shedding of a body part. It is most commonly referred to the process by which a plant drops one or more of its parts, such as a leaf, fruit, flower or seed.

Which hormone is a gas?

Ethylene, the Gaseous Plant Hormone.

What harm does abscission cause to plant?

Fruit production requires the perfect development of reproductive structures. Abscission, a natural process, can occur to facilitate shedding of no longer needed, infected, or damaged organs. If stress occurs during flower development, abscission can intervene at flower level, leading to reduced yield.

Which hormone promotes the abscission of leaves and fruits?

Types of Plant Hormones