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

Culturing, ime day 0 day 1 day 3 day 4 day 5 day 7 count ...

ime day 0 day 1 day 3 day 4 day 5 day 7 count blank 7 10 5 14 9 8 low 45&49 64&70 62&69 75&79 80&82 68&72

Explain the criteria for assessment of folate status, Explain the Criteria ...

Explain the Criteria for Assessment of Folate Status Red cell folate, continues to be used as an important index of folate status. It is suggested that adequate folate status i

Define historical example population genetic theory, Define Historical Exam...

Define Historical Example Population genetic theory? Population genetic theory, first developed by Sir Ronald Fisher, JBS Haldane and Sewall Wright, demonstrated how several ev

Is geometric isomers have the same connectivity, Geometric isomers: Select ...

Geometric isomers: Select one: a. Have the same molecular weight b. Have the same connectivity c. Have a different configuration about a double bond d. All of the above

Factors affects oxygen dissociation curve -organic phosphate, Factors affec...

Factors affects Oxygen Dissociation Curve -Organic Phosphate The presence of organic phosphates in the red blood cells helps to explain many peculiarities of the oxygen dissoc

Hearing equilibrium, EQUILIBRIU M - Cristae and maculae are concerned ...

EQUILIBRIU M - Cristae and maculae are concerned with equilibrium. 1 .       DYNAMIC EQUILIBRIUM - Cristare detect turning or rotational movement of head ( angular ac

Carbohydrates requirement in pectic ulcer, Q. Carbohydrates requirement in ...

Q. Carbohydrates requirement in pectic ulcer? Carbohydrates: These should provide around 55 to 65% of the daily intake. Emphasis - J should be laid on the consumption of 60th s

Factor influencing lipid oxidation - temperature, Factors affecting lipid o...

Factors affecting lipid oxidation Temperature In general, the rate of oxidation increases as the temperature is increased. Temperature also influences the relation betw

Is the epithelium vascularized, Is the epithelium vascularized? How do nutr...

Is the epithelium vascularized? How do nutrients and oxygen reach the epithelium? Why is this feature a significant evolutionary acquisition? Epithelia are not vascularized (ca

How do the cdnas vary from the original genes, How do the cDNAs vary from t...

How do the cDNAs vary from the original genes? A. The inserted cDNA copies lack enhancers, promoters and introns. B. The genomic structures of the original gene and the ins

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