Operculum - seed appendages, Biology

Assignment Help:

Operculum - Seed Appendages

The term operculum is applied to a plug-like structure formed in the micropylar portion of the seed by proliferation of cells at the tip of the inner integument or the nucellus. An operculum has been observed in seeds of many monocotyledonous families, such as the Commelinaceae, Musaceae, Lemnaceae and Zingiberaceae, and a few dicotyledonous families like Bignoniaceae and Nymphaeaceae.

In Lemna paucicostata, cells at the tip of the inner integument undergo a remarkable expansion after fertilization and form a dome-shaped, stopper- like operculum. Cells of the operculum are thick-walled and contain an orange-red substance. During germination of the embryo the operculum becomes detached from rest of the seed and facilitates emergence of the embryo.


Related Discussions:- Operculum - seed appendages

Define nutritional requirements for extreme environments, Define Nutritiona...

Define Nutritional Requirements for Extreme Environments? Human beings have been able to survive and work under extreme environments of almost all regions of the earth, from po

Describe the plasma membrane of the beta-islet cell, Insulin binding to ins...

Insulin binding to insulin receptors in the plasma membrane of a A. liver cell will lead to an enhance in the intracellular amounts of cAMP in the liver cell. B. beta-islet

Radiobiology, Radiobiology : This is the study of effects of radiations on ...

Radiobiology : This is the study of effects of radiations on living organisms. Radiobiology is a branch of science which concerned with the action of ions. Radiobiology is the radi

How d-glucose differs from d-galactose, D-glucose differs from D-galactose ...

D-glucose differs from D-galactose only in the arrangement around carbon 4. Therefore D-glucose and D-galactose are- Select one: a. enantiomers b. epimers c. mirror ima

What are some human diseases caused by virus, What are some human diseases ...

What are some human diseases caused by virus and what are their respective modes of transmission? The main viral diseases transmitted by respiratory secretions (cough, sneezes)

Atp, what is atp explain in detail?

what is atp explain in detail?

Ventricular arrhythmias-peri operative problems, Ventricular Arrhythmias : ...

Ventricular Arrhythmias :  These include premature ventricular contractions (PVC), ventricular tachycardia (VT) and ventricular fibrillation (VT). At times they may be respon

Carbohydrates, Carbohydrates are the next important nutrients as they have ...

Carbohydrates are the next important nutrients as they have to perform a variety of functions such as: 1) Provide major source of energy 2) Breakdown of fatty acids and preve

Which of the vertebrate classes are warm-blooded, Which of the vertebrate c...

Which of the vertebrate classes (a) are 'warm-blooded', (b) reproduce by laying eggs?   (a) Birds and mammals are 'warm-blooded'. (b) Fish, Amphibia, Reptiles

Define general characters and classification of arthropoda, Define General ...

Define General Characters and Classification of Arthropoda? These are metamerically segmented animals with an exoskeleton of cuticle. Scliizocoelic coelom is much reduced and is

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