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.
Q What are the kinds of cell respiration? There are two types of cell respiration aerobic cell respiration a reaction with participation of molecular oxygen (O2) and anaerobic
Explain TechnologicaI advances of clinical dietitian TechnologicaI advances in nutritional support for the critically ill have enhanced the clinical dietitian's role. In the
What is a terrestrial organism? 'Terra' is the Latin word for earth. Thus, an animal that lives on the surface of the earth is known as terrestrial. This is the similar root wo
a) In what ways do farmers try to improve the quality of (i) their soil, (ii) their crop plants? b) What other steps do farmers take to maximise the yield from their
Soil is upper crust of earth which support land plants and animals. It is defined as addition of substances to the soil, which adversely affect physical, chemical? And biologica
Oxidation-reduction Potential (ORP) ORP is related to the concentration of oxidizers or reducers in a solution, and their activity or strength. It provides an indication of th
Relationship of Ecology with Other Disciplines of Biology In order to understand the scope and relevance of ecology let us consider its position in relation to other biological
The importance of the brain in our everyday lives can never be underestimated. The brain has physical properties that are in a constant state of flux. The brain never rests totally
Whenever a chromosome is replicated the replication machinery passes by the nucleosomes without deleting the histones from the DNA. How this happens is since not fully understood.
Q. What is connective tissue proper? The name connective tissue proper is used to designate the connective tissue that fills interstitial spaces as opposed to the specialized c
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