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!
Sporophytic Incompatibility
The recognition and rejection reactions in a SSI system occur on the stigma surface, placing barriers for pollen germination or penetration of pollen tube into the stigma. Thus the pollen grains either fail to germinate or the small tube they put out is inhibited by callose deposition at the tip. The papillae at the stigma also develop a lenticular callose plug within 10 min after pollination. Infact, in incompatible cases, inhibition of varying degrees operates at every level starting from pollen adhesion, hydration, germination and tube entry into the stigma. In some plants stigma is covered with a cuticular layer such that the incompatible pollen tube fails to penetrate.
Various studies have proved the necessity of enzyme cutinase in eroding the cuticle. This enzyme is activated only by the compatible cases. Incompatible stigmas may lack copious exudate, but dry stigmas have a hydrated layer called pellicle over the cuticle. This pellicle consists of a lipid layer where a mosaic of proteins floats. The pellicle probably originates by the protrusion on the surface of the papillae through discontinuities in the cuticle. As soon as pollen is received by the stigmatic surface the papillate cells exude moisture. The incompatibility is the result of interaction between protein fractions of exine and stigma.
Q. Describe the phylogenetic system of classification? 1) Hutchinson believed in Monophyletic origin of Angiosperms from a hypothetical group, which he' named, as Proangiosperm
Define the Effects of Dietary Fibre? After reviewing the properties of fibre, we will now study various physiological effects of fibre, as it passes through the gut. The effect
The Stem Cells The Stem Cells are undifferentiated mesenchymal cells that can proliferate and differentiate into many other types of cells.These are Clonogenic cells capable of
Propane boils at -46oC. Propanol boils at 97oC. The difference is attributable to- Select one: a. The fact that propanol is much heavier b. The fact that propanol ionizes all
H a e m o r r ha g i c septicaemia It is also known as septicemic pasteurellosis or barbone and the disease is clinically characterized by high fever, excessive saliv
Q. Explain microbiology of water? Ans. Unlike air, natural waters contain their natural flora, as well as, microorganisms from soil and possibly from animals and se
Do the -R groups bound to the central carbons participate in the union among amino acids? The peptide bond attaches the nitrogen of the amine group of one amino acid to the car
If a diploid sperm fertilized a haploid egg, what would the result be? a.Haploid (n) b.Diploid (2n) c.A mixture of diploid (2n) and haploid (n) d.Triploid (3n)
Ascariasis This disease is found in young calves causing digestive disturbances and poor growth. E t iology: It is caused by Toxocara vitulorum in cow and buffal
rRNA structure and synthesis assignment
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