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

What is implant success, Implant success 1) An individual, unattached i...

Implant success 1) An individual, unattached implant is immobile when tested clinically. 2) A radiograph that does not demonstrate any evidence of perimplant radiolucency.

What is commensalism, What is commensalism? Commensalism is the ecologi...

What is commensalism? Commensalism is the ecological interaction in which one individual advantage while the other is neither benefited nor harmed. Commensalism is a harmonious

Can we prevent ketoacidosis, Q. Can we prevent ketoacidosis? Normally, ...

Q. Can we prevent ketoacidosis? Normally, while maintaining a good sugar control, there is a very little danger of ketoacidosis. One should test for ketones under the following

Genetics, polymorphism and its causes

polymorphism and its causes

Eastern/western/venezuelan equine encephalitis, Eastern/Western/Venezuelan ...

Eastern/Western/Venezuelan equine encephalitis This encephalitis causing group of viral diseases of wild birds including pheasants, chickens, turkeys, ducks and pigeons with a

Explain about the lignans, Explain about the Lignans? Lignans are diphe...

Explain about the Lignans? Lignans are diphenolic compounds formed by dilnerization of 2 cinnamic acid residues. Most lignans apparently pass through the GIT as fibre. Some lig

What is an erlenmeyer flask and how is it used, What is an Erlenmeyer flask...

What is an Erlenmeyer flask and how is it used? It is same to a beaker, except that it gets narrower at the top. It is use to hold liquids and do reactions in it.

Explain the relation between chromatin and chromosome, What is the relation...

What is the relation between the concepts of chromatin and chromosome? Are euchromatin and heterochromatin part of chromosomes? Every filament of chromatin is a complete DNA mo

Symptoms of ulcerative colitis, Q. Symptoms of ulcerative colitis? As d...

Q. Symptoms of ulcerative colitis? As discussed in the case study above, the common symptoms are: 1. Mild abdominaI discomfort, an urgent need to defecate several times a da

Osmoregulation in terrestrial environment, Osmoregulation in Terrestrial En...

Osmoregulation in Terrestrial Environment  Earlier you have learnt about osmoregulation in aquatic environment. In this section, we shall study how the terrestrial animals cop

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