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.
Neurosecretory Cells and Neurosecretion We have before said that the neurosecretory cells are an important component of the non- chordate endocrine system. Of course, they are
What are the trends of the gametophyte in the evolution of plants? A tendency of the gametophyte evolution in plants has been towards the formation of gametes that are independ
Define the Redia Larva? Redia is the third larval stage in the life cycle of F. heputicn. Redia develops from the germ cell Is of the sporocyst and comes out of the sporoc
Theodosius Dobzhansky and Boris Spassky demonstrated the working of normalising selectioion a behavioural trait in two populations of Drosophida pseudobscura. The two populatiors w
Define Efficiency - terminologies used in chromatography? Efficiency in chromatography is expressed as number of theoretical plates. H = L/N Where, H is heigh
Explain Transition Period from Renaissance to Modern Period? The transition period from the Renaissance to the Modern period produced many notable workers and much literature.
Foraminiferans - Protozoan Foraminiferans are largely benthic marine species. They have multi chambered calcareous tests or shells with numerous pores, hence the name foramini
Advantages (1) Liquid and gaseous fuels can be manufactured from solid fuels. (2) Relatively cheap and easily available. (3) These are easy to transport. (4) A
Q. Show Appearance of food product? Appearance can be judged by the eye. Appearance factors include such things as size, colour, uniformity, absence of any defect, shape, whole
Oxidation of succinate to fimarate: This reaction is catalyzed by succinate dehydrogenase and FAD' is needed as a cofactor. Malonate, structural of succinate, competitively
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