Suspensor - pollen biology, Biology

Assignment Help:

Suspensor - Pollen Biology

The structure and function of suspensor have not been given adequate attention. During the last decade, however, investigations have produced noteworthy results. These include ultra structural, isoenzymatic, physiological, and in vitro experiments. A great deal of variation occurs in suspensor structure, probably modified to support the developing embryo. During 1950's and 1960's embryologists believed that it the suspensor is merely a morphological organ that pushes the embryo deeper into the more friendly environs of endosperm. This view is gaining reconsideration. The suspensor plays a more dynamic role than was hitherto assigned. The special kind of plastids present in legumes such as Pisum and Phaseolus and in Ipomoea and Tropaeolum show remarkable ultra structural changes around late heart-shaped stage of embryo.

The significance of these unusual plastids needs to be determined. Another feature of interest is the presence of wall embayments lined by plasma membrane in the suspensor cells supposed to be involved in short distance translocation of metabolites similar to transfer cells. Some experiments demonstrate the significance of presence of suspensor for proper development of the embryo. During early stages, removal of suspensor reduces embryo development but, at later stages, it has no effect. However, it is possible to replace, at least partially, the effect of suspensor loss by providing gibberellins in the culture medium. The finding is further substantiated by quantitative analysis of GA present in the suspensor and embryo proper cells. This GA has been identified as gibberellin Al. The relative concentrations of auxin in embryo proper and suspensor of Tropaeolum majus have been studied through single ion detection. The suspensor proper yields significantly higher concentrations of auxin. Likewise, in Phaseolus, the suspensor of heart-shaped embryo shows more cytokinin. However, at mid- cotyledonary stage, suspensor contains low cytokinin and the embryo seems to become autonomous for cytokinin.


Related Discussions:- Suspensor - pollen biology

Explain metabolic changes during infection, Explain Metabolic changes durin...

Explain Metabolic changes during infection With  the rise  in body  temperature above normal (98.4 0 F or 37°C) due  to infection several metabolic changes occur  in  the body

Explain the the system of the nomenclature, Explain the The system of the n...

Explain the The system of the nomenclature The system of the nomenclature and the classification of enzymes is based exclusively on the reaction that is catalyzed and does not

Inhalation route for injection, Inhalation Route for Injection Therapi...

Inhalation Route for Injection Therapies that can be administered by inhalation are oxygen, humidification-cool mist and steam, administering local medication. The commonly u

Sources of stem cells-pulp tissue revascularization, A) General:   u...

A) General:   umbilical cord  Placenta  Bone marrow  Ophthalmic cornea { conjectiva of the eye }  Kidney  Spleen  (B) Dental:  Dental pulp

How the brain influences or controls immune system, How the brain influence...

How the brain influences or controls immune system Scientists are still working to determine to what degree, and how, the brain influences or controls immune system functions,

What are the major novelties presented by fishes, Q. What are the major fea...

Q. What are the major features of fishes associated to the habitat where they live? Fishes are all aquatic animals and thus they have a hydrodynamic elongated body appropriate

Explain about diabetes mellitus, Q. Explain about Diabetes Mellitus? Di...

Q. Explain about Diabetes Mellitus? Diabetes Mellitus is a metabolic disorder characterized by chronic hyperglycemia (increased sugar) with disturbances of carbohydrates, fats

Illustrate about components of an angioplasty system, Q. Illustrate about C...

Q. Illustrate about Components of an Angioplasty System? 1) Guiding catheter: The ideal guiding catheter must have a lumen diameter i.e. at least twice that of the diagnostic c

Explain the biochemical approach in taxonomy, Explain the Biochemical Appro...

Explain the Biochemical Approach in Taxonomy Comparative biochemistry is being used increasingly in the systematic of animals, both for identification of organisms as well as f

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