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

Pathophysiology of acute glomerulonephritis, Pathophysiology   The exac...

Pathophysiology   The exact mechanism of glomerulonephritis  is still under investigation. The dies'ease is characterised by deposition  of immune complexes  consisting of anti

Recurrent type, Recurrent Type In this type, euspory (seen in normal ...

Recurrent Type In this type, euspory (seen in normal cases) is replaced by aneuspory (Diplospory) because of irregular meiosis. When the spore mother ceIl functions directly

External ear, EXTERNA L EAR - It is an oval shaped, some what funne...

EXTERNA L EAR - It is an oval shaped, some what funnel like, skin covered flap of elastic cartilage and muscles. It's outer stiff ridge is called hellix. Lower flexibl

Define procedure for measurement of ph, Define Procedure for Measurement of...

Define Procedure for Measurement of pH? To ensure reliability of the pH readings, you should first calibrate the pH meter. You should adjust the pH meter so that the readings a

Enzyme - linked immunosorbent assay (elisa), E n z y m e - l...

E n z y m e - linked immunosorbent assay (ELISA):   ELISA in its var io us modifications e.g. plate ELISA, sandwich ELISA, competitive ELISA, ELISA strip or

What is the definition of polyphenols, What is the Definition of Polyphenol...

What is the Definition of Polyphenols? Polyphenols are the compounds that contain an-ON group attached to the benzene ring. The main classes are: flavonoids, phenolic acids and

Explain adverse effects of cidofovir, Explain Adverse Effects of Cidofovir ...

Explain Adverse Effects of Cidofovir About 25% of patients discontinue cidofovir because of adverse effects such as nephrotoxicity, neutropenia and metabolic acidosis. Iritis,

What is the ability of two oxygens to remove h+ protons, What makes the clu...

What makes the cluster of atoms of carboxylic acid functional group an acid? a) a non-polar O-H bond near another electronegative oxygen. b) an ionic O-H bond near another el

Sequence for the beta actin gene, The sequence for the Beta Actin gene (ACT...

The sequence for the Beta Actin gene (ACTB) is given below. Which pair of primers (designed to amplify the entire sequence below) could be used to successfully produce the beta act

Translation in prokaryotes, Term Translation or protein synthesis, is quite...

Term Translation or protein synthesis, is quite similar in eukaryotes and prokaryotes. We will look at the details of the process in prokaryotes and consider the differences in euk

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