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

Excretion, State the excretory organelles of various organisms

State the excretory organelles of various organisms

What is splitin first heart sound, What is Splitin first heart sound ? ...

What is Splitin first heart sound ? In complete RBBB, due to delay of tricuspid closure, the split is wide. In complete LBBB, due to delay of mitral closure the S I is single.

Describe the lymphatic organs in human biology, Describe the Lymphatic Orga...

Describe the Lymphatic Organs in human biology? The lymphatic organs include the lymph nodes, the spleen, the thymus gland, the tonsils, and Peyer's patches, all containing lym

Explain progressive loss of the axonal myelin sheath, What are some disease...

What are some diseases characterized by progressive loss of the axonal myelin sheath? Multiple sclerosis is a severe disease caused by progressive destruction of the myelin she

Acute rheumatic fever, Acute Rheumatic Fever   Rheumatic  fever is an i...

Acute Rheumatic Fever   Rheumatic  fever is an inflammatory disease that usually follows infection of upper respiratory tract with group A beta hemolytic streptococci. It  is c

Assessment and management of aortic stenosis, Assessment   The severity...

Assessment   The severity of symptoms depend on degree of obstruction.  In case of severe obstruction,  ECG shows right ventricular or biventricular hypertrophy. Cardiac cathet

How does fecundation occur in angiosperms, After the pollination how does f...

After the pollination how does fecundation occur in angiosperms? In these plants is fecundation dependent on water? After the pollination one of the sperm nuclei from the polle

Haemodynamic study of constrictive pericarditis, Q. Haemodynamic Study of c...

Q. Haemodynamic Study of constrictive pericarditis? Simultaneous right and left heart studies are useful. Due to exaggerated waves in atria, W-shaped atrial pressure tracing wi

Assessment of regional wall motion abnormality, Q. What is Regional wall mo...

Q. What is Regional wall motion abnormality? Ans. A critical occlusion of a coronary artery leads to myocardial ischemia which is manifested as regional wall motion abnorm

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