Abscission - effects of plant growth regulators, Biology

Assignment Help:

Abscission - Effects of Plant Growth Regulators

Abscission of leaves and fruit is one of the more obvious characteristics of senescence. Leaves do not fall simply because they are dead. A zone of cell division, the abscission zone, develops near the base of the leaf so that numerous cross walls form at right angles to the long axis of the petiole. Then pectinases and cellulases are induced in these cells of the abscission zone. These dissolve the lamellae of the cross walls of these cells, so that the petiole breaks off, The vascular connections break and usually become plugged by the formation of tyloses (deposits of gummy substances) and layers of corky cells.

Thus, at least two important events are involved in abscission: cell division and the induction of hydrolases. Both of these are processes of active metabolism and must therefore, be a programmed part of the development of the plant. Causes of abscission involve several interlocking events. It seems possible that certain growth-inhibiting substances may be involved. ABA clearly stimulates abscission in cotton petiole explants, as does GA. Addition of auxin to the petiole or blade of a senescing leaf prevents the formation of the abscission layer, and thus inhibits abscission.


Related Discussions:- Abscission - effects of plant growth regulators

What is the process of evolution, Why acquired traits are not directly rela...

Why acquired traits are not directly related to the process of evolution? As acquired traits are not genetically determined, they cannot be passed on to offspring. Therefore,

A common biocontrol agent for the control of plant diseases, A common bioco...

A common biocontrol agent for the control of plant diseases is : 1. Baculovirus 2. Bacillus thuringiensis 3. Glomus 4. Trichoderma Trichoderma

Define methods for estimation of iron and haemoglobin, Define Methods for E...

Define Methods for Estimation of Iron and Haemoglobin? In this section we shall study the procedure involved in estimation of iron in any sample first followed by a review on t

Selection of foods for diabetic patients, Q. Selection of foods for diabeti...

Q. Selection of foods for diabetic patients? Some handy guidelines for selection of foods for diabetic patients is presented next. You may be aware that some foods need to be

What are the so-called good and bad cholesterol, What are the so-called "go...

What are the so-called "good" and "bad" cholesterol? Lipoproteins are complexes made of lipids (triglycerides and cholesterol) and proteins. The lipoproteins present dissimilar

Blunt or non-penetrating injury, Blunt or Non-penetrating Injury When ...

Blunt or Non-penetrating Injury When body is struck by a blunt object such as steering wheel or blows to chest with blunt object. External injury may appear minor but the

Effects of noise - noise pollution, Effects of Noise - Noise Pollution ...

Effects of Noise - Noise Pollution Noise can affect in the following three ways: Interferes with communication, Diminishes hearing and Affects health and even

Why is the sun the motor of the water cycle, Q. Why is the sun the "motor" ...

Q. Why is the sun the "motor" of the water cycle? The sun can be considered the motor of the water cycle for the reason that upon its energy the transformation of liquid water

Skin, what is the warmest and coldest parts of the boy

what is the warmest and coldest parts of the boy

Ecological significance - conservation of wildlife, Ecological Significance...

Ecological Significance - Conservation of Wildlife  Besides serving as a valuable genetic reservoir, each species interacts with other species and plays a role in the transfe

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