Sterility in angiosperms, Biology

Assignment Help:

Sterility in Angiosperms

Sterility in angiosperms may arise due to several causes. Either the anther may not be formed, or anthers are formed but meiosis may be abnormal.

A. In situations where anthers are not formed, they may take abortive forms and appear like petals or sepals. These conditions are referred to as petaloid and phyllody respectively. There are even cases where anther formation may be suppressed altogether. These cases of pollen sterility have premeiotic determination.

B. There are other examples in which anthers are produced but meiosis is abnormal resulting in the formation of non-viable pollen.

C. Sometimes normal pollen grains are formed but they are not released. This results from failure of anther dehiscence. Such a situation is also described by the term contabiscent anther.

D. Sometimes meiosis is normal but abortion can take place due to premature dissolution of callose. This can occur at any stage during microsporogenesis.


Related Discussions:- Sterility in angiosperms

Products of hemp plant, PRODUCT S OF HEMP PLANT - Four drugs - bhan...

PRODUCT S OF HEMP PLANT - Four drugs - bhang, ganja, charas & marijuana obtained from Cannabis indica and C. sativa of family Moraceae . Main alkaloid is tetrah

Formation and role of hypoblast, Formation and Role of Hypoblast Hypo...

Formation and Role of Hypoblast Hypoblast is made as a result of two processes. First, some cells individually leave the blastoderm and move down via poly invagination into t

Describe aerobic respiration in krebs cycle, Q. Until the Krebs cycle, aero...

Q. Until the Krebs cycle, aerobic respiration can be described without mentioning oxygen, the chemical element after which the reaction gets its name. Where in the process does thi

What are the hormones secreted by the adrenal cortex, Q. What are the hormo...

Q. What are the hormones secreted by the adrenal cortex? What are their respective functions? The cortical portion of the adrenals secretes hormones of the corticoid (or cortic

Antibiotics, ANTIBIOTICS - Chemicals produced by microorganism that ...

ANTIBIOTICS - Chemicals produced by microorganism that inhibit the growth of other microorganism. Such microorganism which produces the antibiotics are antibiont . Wh

Blastula, Blastula is the ball of cells surrounding a fluid-filled cavity ...

Blastula is the ball of cells surrounding a fluid-filled cavity (known as blastocoel) which is produced by the cleavage of a zygote.

What are active and passive immunization, Q. What are active and passive im...

Q. What are active and passive immunization? According to the duration of the protection how do these types of immunization differ? Active immunization is that in which an anti

Define clinical feature and medical complication for bulimia, Define Clinic...

Define Clinical Features and Medical Complications for bulimia? Unlike, anorexia nervosa, in bulimia you will find that symptoms are more difficult to detect because patients a

Explain about the musculoskeletal system, Explain about the Musculoskeletal...

Explain about the Musculoskeletal System? Osteopenia (decrease in bone mineral content) is observed with aging. There is an average of 30% decline in the bone mineral density f

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