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.
Nitrogen is needed mostly for the synthesis of amino acids and nucleotides. Sources of nitrogen can be obtain from organic as well as inorganic sources, but the whole target is the
Q. What is the difference between type II diabetes mellitus and type I diabetes mellitus? Type I diabetes also known as insulin-dependent diabetes (as this name is not adequate
The marine biomes consist of the earth's oceans and its associated areas like the shorelines, islands, reefs and estuaries. The marine waters contain about 3.5 percent salt, mostly
Graduate student Dee Innay works in a human genome lab, whose goal is to identify the human gene responsible for a form of muscular dystrophy (MD). Dee has mapped the MD gene to a
Active transport is the transport of the molecules against the concentration gradient (from area of low concentration to area of high concentration) with the help of proteins in t
Explain congenital heart disease ? No systematic surveys have been conducted to estimate the incidence of CHD at birth in India and other developing countries. As a result ther
Modes of Respiration Many small organisms obtain oxygen by diffusion through their body surfaces. They do not have any specialised respiratory organs nor do they have blood ci
Insulin is released into the bloodstream by the β cells of the pancreas when blood glucose stages are high after feeding and stimulates glycogen synthesis to kept exces
What are likely to be (a) the coldest, (b) the warmest parts of the body? The extremities of the body (hands and fingers, feet and toes, ears and nose) are likely to be the col
Explain nutritional properties of the eggs Drying of eggs under normal conditions causes little loss of the nutritional properties of the eggs. Vitamin A, vitamin B, thiamine,
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: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd