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!
The Exine Layer
It consists of two layers, inner (nexine) which is continuous and an outer (sexine) the sculptured one. The outer layer has ornamentations comprising rod-like bacula showing terminal expansion which sometimes fuses to form a roof like tectum perforated by micropores. During pollen development, the tapetum releases a mixture called tryphine, consisting of carotenoid lipid droplets and fibrogranular proteins into the thecal cavity. These fibrogranular proteins are enclosed in membrane bound cisternae. In tectate pollen, the released substances of tapetum become incorporated on the surface of pollen grains where cisternae membrane ruptures and protein released through micropores enter the tectum and accumulate in the interspaces of bacula.
Pollenkitt is the pigmented lipid fraction left on the surface of the tectum. Unlike intine, the exine held proteins exhibit only one enzymatic activity. The hydration of pollen is described to be stimulatory in releasing the proteins held in the pollen wall layers. The calculated time taken by the exine held proteins of sporophytic origin to pass out is 30 seconds while the intine of gametophytic origin takes a few minutes. This time difference in the protein release has made it easy to collect both samples separately. In SSI systems therefore the rejection reaction is faster than in GSI system.
why does the removal of the extremity of coleoptile prohibit plant growth?
Explain about the Niacin (nicotinic acid) deficiency? Niacin (nicotinic acid) deficiency classically results in pellagva, which is a chronic wasting disease associated with a c
Q. What does radial symmetry means? What is the kind of symmetry found in chordates? Which are other phyla of the animal kingdom that present species with radial symmetry? Radi
Q. Can Obesity causes the cardiovascular disease? As you know obesity or excessive weight is the primary cause of cardiovascular disease. It is an independent risk factor for h
Explain the molecular difference between fats and oils. How do the differences affect their physical properties?
What is the autotrophic hypothesis on the origin of life? The autotrophic hypothesis on the origin of life asserts that the first living beings on earth were producers of thei
Q. List the stages of process of behaviour change? Stages of behaviour change process: · Unawareness · Awareness · Acquiring knowledge · Motivation · Trial
Define Safety points that should used in the Laboratory? You should be aware of the rules/regulations and the procedures before undertaking any practical work in the laboratory
what is the formula for an amino acid
Q. What is the valve that separates the duodenum from the stomach called? What is its function? The valve that separates the stomach from the duodenum is the pylorus it has the
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