Barriers to fertilisation, Biology

Assignment Help:

Barriers to Fertilisation

Incompatibility can occur anywhere from pollination to syngamy and consequently obstructing fertilisation. The pollen fails to germinate or the pollen tube is inhibited to penetrate the stigma.

The progamic barriers to fertilisation may be on the stigma or in the style at any level from pollen germination to the discharge of male gamete in the vicinity of egg.

On the other hand, syngamy barriers include the inhibition of the entry of pollen tube to the ovary, ovule or within embryo sac. At the stage of pollination the barriers to fertilisation are of morphological and ecological types, whereas, at progamic phase and syngamy physiological barriers occur.


Related Discussions:- Barriers to fertilisation

Adrenal medulla, ADRENA L MEDULLA The adrenal medulla develops from th...

ADRENA L MEDULLA The adrenal medulla develops from the neuroectoderm of the embryo. Medulla consists of chromaffin cells or phaeochromocytes. These cells are connected wi

Determine balanced diet for celiac disease, Determine Balanced Diet For Cel...

Determine Balanced Diet For Celiac Disease? Energy: initially the children are seen to be malnourished, thus 100-120 Kcal/kg body weight/day with gradual increase to 150 Kcal

Some common air pollutants: carbon monoxide, 1.   Carbon monoxide (CO): ...

1.   Carbon monoxide (CO): It is colourless, odourless, tasteless gas and is not soluble in water. Source: CO is produced due to: (i)     Incomplete combustion of fuels

VIRUSES, WHAT IS THE TYPICAL REPRODUCTION CYCLE OF A DNA VIRUS

WHAT IS THE TYPICAL REPRODUCTION CYCLE OF A DNA VIRUS

What are nadph and nadp, Q. What are NADPH and NADP? NADP is the short ...

Q. What are NADPH and NADP? NADP is the short form of the nicotinamide adenine dinucleotide phosphate cation, a hydrogen acceptor. NADPH is made when NADP binds to one hydrogen

What is av block, Q. What is AV Block ? First Degree AV Block At ...

Q. What is AV Block ? First Degree AV Block At rest commonly disappears with exercise owing to the vagal withdrawal. The development of a prolonged PQ segment after exerc

Do echinoderms have an excretory system, Q. Do echinoderms have an excretor...

Q. Do echinoderms have an excretory system? How is excretion done in these animals? Echinoderms do not have an excretory system their excretions are eliminated by diffusion.

Techniques of counselling, Counseling is a process whereby a qualified pers...

Counseling is a process whereby a qualified person purposefully assists another person to handle his or her problems. Counselling is not just giving advice. It is dependent  on mut

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd