Heteromorphic types - intra specific incompatibility, Biology

Assignment Help:

Heteromorphic Types - Intra specific Incompatibility

Plants of the same species produce flowers that differ in morphology. This involves two (distyly) or three (tristyly) morphologically distinct types of flowers showing similar breeding behavior (mating type) within a species. The difference in the mating types lies in the position of stigma and anthers (heterostyly). Distyly is under the control of a single gene complex with two alleles, S (for short style-dominant) and s (for long style-recessive). Long style individuals are, therefore, homozygous recessive (ss) and short style are heterozygous (Ss). This ensures approximately equal ratio of short and long-styled individuals from compatible crosses.

Tristyly refers to three floral morphs with individuals having either long, mid- or short- styled flowers. Each type has stamens of two heights corresponding to the height of stigma in the other two forms. Successful pollination results only between forms having stigma and stamens of the same height. Two genes, M and S with two alleles each control tristyly. Gene S is epistatic to M. Homozygous recessive for both the genes (ssmm) determine long style, mid-style have ssMM or ssMm and short-styled flowers carry the genes SsMm or Ssmm or SsMM. In both di- and trimorphic forms sporophytic incompatibility operates.


Related Discussions:- Heteromorphic types - intra specific incompatibility

Examine the benefits and risks bird flu, Examine the benefits and risks bir...

Examine the benefits and risks bird flu research poses to society. Indicate if you believe there are more benefits or more risks associated with this research, and give a rationale

Proteins, Amino Acid - compound with an amino group and a carboxyl group a...

Amino Acid - compound with an amino group and a carboxyl group attached to a central carbon Proteins make up 50% of dry mass of cells in our bodies E.g. of proteins are

Explain about gamma diversity, Q. Explain about gamma diversity? Gamma ...

Q. Explain about gamma diversity? Gamma (g) richness refers to the rate of change across larger landscape gradients and gamma diversity is a measure of the overall diversity fo

Risk factors for gdm, Q. Risk Factors for GDM? If any of the following ...

Q. Risk Factors for GDM? If any of the following risk factors are present in a woman, she may develop GDM: 1) Presence of obesity. 2) If any family members (parents, brot

What are the roles of atp and nadph, Q. What are the roles of ATP and NADPH...

Q. What are the roles of ATP and NADPH in the chemical stage of photosynthesis? NADPH acts as reductant of carbon dioxide it delivers highly energetic hydrogen to precursor mol

Functions of the pancreas, The pancreas performs digestive and hormonal fun...

The pancreas performs digestive and hormonal functions. The enzymes secreted by the exocrine tissue in the pancreas help in the break down of carbohydrates, fats, proteins, and

Explain the obligatory losses of nutrients, Explain the Obligatory Losses o...

Explain the Obligatory Losses of Nutrients? Obligatory losses of nutrient are defined as 'the losses that occur when an individual is put on a diet free of that nutrient'. For

Define iron deficiency anaemia during pregnancy, Define Iron deficiency ana...

Define Iron deficiency anaemia During pregnancy? Iron deficiency anaemia (microcytic hypo chromic anaemia) is widespread among adolescents and young women during their reproduc

Sphaerosome, Sphaerosome Also known as Plant lysosome , because the...

Sphaerosome Also known as Plant lysosome , because they contain hydrolytic enzymes. Hanstei n first observed them and called microsomes . Discovered by Dangeared

What is the radula, What is the radula? What is the function of this organ?...

What is the radula? What is the function of this organ? Some molluscs have a tongue-like structure with harsh saliences similar to small teeth. This structure is called radula

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