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.
Modern Biology Increasing advancement in biotechnology has brought about a veritable explosion of Biological knowledge since early 1950s.This vast modern biological information
What is an evolutionary tree? Is there a precise evolutionary tree known by science that explains the emergence and origin of every type of living being? Evolutionary tree is t
Q. Importance of Primary prevention of diabetes mellitus ? Primary prevention has been found to be cost effective in the long run as it reduces unwarranted human suffering. Pre
The pancreas performs digestive and hormonal functions. The enzymes secreted by the exocrine tissue in the pancreas help in the break down of carbohydrates, fats, proteins, and
what are characteristics of flagellata class ?
The Different systems of the body are: 1) Nervous System 2) Respiratory System 3) Cardiovascular System 4) Neurological and Sensory System 5) Gastrointestinal Syste
Q. What are the Components of mitral valve apparatus? 1) Annulus: Annulus is a saddle shaped structure with medial and lateral portions forming the basal points and anterior a
Exploitation of Forests Exploitation of our forests for commercial purposes and for food and fodder cannot be stopped completely because of symbiotic relationship between fore
What is the typical biological function of the connective tissues? How is this function associated to the main features of its cells? The typical function of the connective tis
Succession - Community Change The factors like fire, floods and human interventions affect an ecosystem considerably. They often lead to the depletion or stripping off of orig
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