Suspensor - pollen biology, Biology

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.

Posted Date: 1/24/2013 5:47:31 AM | Location : United States







Related Discussions:- Suspensor - pollen biology, Assignment Help, Ask Question on Suspensor - pollen biology, Get Answer, Expert's Help, Suspensor - pollen biology Discussions

Write discussion on Suspensor - pollen biology
Your posts are moderated
Related Questions
Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Advantages of Pyramid of Energy A pyramid of energy must be based on determination of the actual amounts of energy that individuals take in, how much they burn up during metab

#question names of 10 zoo flagellates

Immunogenicity Based on immunogenicity studies and experience with other vaccines, the new meningococcal conjugate vaccine (Menactra) should be highly effective in preventing m

Defective extra-preputial protrusion of the penis This defect is a result of hypoplasia or a defective penile erection due to a congenital mucosal fold – the frenulum - betwee

What are homologous chromosomes? Which are the human cells that do not have homologous chromosomes? Chromosomes have genes (genetic information in the form of nucleotide sequen

Define Regulation of Water Balance - For the Digestive Process? For the digestive process alone, the estimated daily volume of fluid that enters and leaves the gastrointestinal

Explain about the plateau effect - Energy Balance? You must have noticed that when people start following weight reducing diets, they lose weight rapidly in the beginning, then

Q. Carbohydrates requirement in pectic ulcer? Carbohydrates: These should provide around 55 to 65% of the daily intake. Emphasis - J should be laid on the consumption of 60th s

Describe the term - Intellectual Processes scales The 269 items are divided into 11 content scales, each of which may be administered individually. Since these scales contain v