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
Define Advantages and Disadvantages of Measurement of Cell Mass? Advantage 1. It is a useful technique for estimating fungal and actinomycetes growth. Disadvantages 1.

Q. Which structures of the body have more bones for their size than any other part of the body? Hand and wrist have more bones in them for their size than any other part of bod

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4

Explain the Principles of Taxonomy? The goal of taxonomy is to develop a workable classification that reflects evolutionary relationships and provides identification and no

Q: What are disaccharides? Although theoretically disaccharides could be made up of two trioses, tetroses, pentoses but all naturally occurring disaccharides contain hexose mol

What is the etiological agent and the main manifestations of cholera? Cholera is a bacterial disease caused by the Vibrio cholerae. The disease is transmitted by fecal-oral rou

Collection of Blood It is a procedure done routinely for diagnosis. It can be done in various ways. 1) Capillary Sampling  The heel is the most useful area i

Explain the OBJECTIVES of history of mart disease? After reading this unit, you should be able to: 1. Understand the importance of Cardio-vascular diseases as the leading cause

Implementation of Nursing Care Isolate the Child: When the child is admitted with suspected meningitis, the nurse has to take care that child's isolation is essential to p

Define the Symptoms in Blood of Pernicious Anaemia? Blood: The RBC count is low-1.5-2.5 million per mm 3 (normal range is 4.5- 5.5 million per mm 3 ). The average diameter o