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

Explain about the importance of vitamins, Explain about the Importance of V...

Explain about the Importance of Vitamins? Vitamins are the organic substances that act as coenzyme and/or regulator of metabolic processes. There are 13 known vitamins, most of

Pathophysiology of chronic wasting disease, Q. Pathophysiology of Chronic w...

Q. Pathophysiology of Chronic wasting disease? We all know that heart attack i.e. myocardial infarction is not the beginning but a last stage representing acute clinical manife

State the phases of soil genesis, State the phases of soil genesis Soil...

State the phases of soil genesis Soil genesis embodies two distinct phases. One is weathering that involves disintegration and decomposition of rocks and minerals, the other is

Combined use of diuretics, Combination of diuretics may be indicated in pat...

Combination of diuretics may be indicated in patients previously resistant to furosemide alone. Profound diuresis and clinical improvement may occur after the addition of metolazon

What are the three periods into which interphase, Q What are the three peri...

Q What are the three periods into which interphase are divided? Interphase is the preceding phase to the mitotic division. It is divided into three periods, G1, S and G2 the le

Explain about the food analysis and chemistry, Explain about the Food analy...

Explain about the Food analysis and chemistry? Investigation of the basic composition and physical, organic and biochemical properties of food constituents at the molecular lev

Stress - responses of plants to stress, Stress - Responses of Plants to Str...

Stress - Responses of Plants to Stress Let us recall what happens within the natural communities occupying the same habitat. The relative location of two plants may place them

Zoonoses disease-tuberculosis, Tuberculosis Tuberculosis is a specific ...

Tuberculosis Tuberculosis is a specific communicable disease involving the pulmonary and extra- pulmonary tissues and is characterized by chronic clinical manifestations. The i

Pain - criteria for endosteal implants, Q. Pain - criteria for endosteal im...

Q. Pain - criteria for endosteal implants? Pain and tenderness are subjective criteria and depend on patient's  interpretation of the degree of discomfort. Pain is defined as u

Explain prevention of endocarditis, Explain prevention of endocarditis ...

Explain prevention of endocarditis Many physicians believe that antimicrobial prophylaxis before process that may cause transient bacteremia can stop endocarditis and prostheti

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