Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Seed Coat Effects
In some seeds dormancy is imposed by the presence of the seed coat; if this is removed, the seed germinates. Two possible types of mechanisms could be involved, one biochemical or physiological and the other purely mechanical.
Scarification
The seed coat is nearly impervious to the diffusion of gases. Wareing's group found that seeds of Birch (Betula Pubescens), which would not germinate intact, would do so if the seed coat were scratched or broken. Moreover, added oxygen greatly stimulated germination of such damaged seeds. Evidently the embryos themselves were not dormant; they would germinate if isolated from the seed An alternative possibility is that the seed coat might prevent the leaching out of a diffusible inhibitor. The second, or mechanical alternative has been investigated by Y. Esashi and A.C. Leopold using seeds of Xanthium pennsylvanicum (also called Xanthium strumarium), the cocklebur.
This plant produces two kinds of seeds in each fruit large, non dormant ones and small, dormant ones. The investigators used the specially designed apparatus to show that neither type of seed generates enough force to rupture the testa during imbibitions. During growth, however, the large, non dormant seeds generate sufficient force to break it whereas the smaller dormant seeds do not. This shows, for Xanthium at least, that the long held opinion that the embryo must generate sufficient force during germination to rupture the seed coat is correct. Moreover, it is clear that the forces generated by imbibitions alone are not sufficient. Active growth is also needed.
Q. Carbohydrate distribution in insulin? The carbohydrate distribution varies with the type of insulin prescribed. For example, in case of regular insulin 1/3rd each carbohydra
Explain Clinical stigmata of specific syndromes in heart disease? Clinical stigmata of specific syndromes: Evidence of preseilce of chromosoinal anomalies or other syndromes
Q. What is hypercholeslerolaemia? Cholesterol: It is a natural component of foods such as mutton, pork, ham, sausages, lamb, chicken, eggs (yellow), whole milk, cheese, ice-cre
What is the phenotype? Phenotype is every observable characteristic of a living being conditioned by its genes. A few phenotypes may be altered by nongenetic factors (for insta
Is there a difference between something that is alive and something that is a living organism?
A haploid cell contains: A.one half of a complete set of chromosomes B.several complete sets of chromosomes C.the correct number of chromosomes D.two complete sets of chromosomes E
Question 1: Enlist the applications of programming and encoding in Pharmaceutical industries Explanation on what is programming and encoding in Pharmaceutical industries
Explain about the Paediatric and Geriatric Nutrition? Every stage has its unique requirements due to different changing needs. Adequate and optimum nutrition support is very im
Briefly describe the principal lines of defence against bacteria entering the blood system. A blood clot forms a barrier to entry by bacteria. White cells ingest and kill bacte
Q. Define Osseointegration from patients, microscopic and biomechanical points of view. a) From the view of the patient . An implant fixture is osseointegrated if it provid
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd