Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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.
A 21-year-old woman presents with a 3-month history of malaise, joint pain, weight loss, and sporadic fever. Her temperature is 38°C (101°F). The serum antinuclear antibody (ANA) t
Q. How is it explained that a person with the spinal cord sectioned at the cervical level is still able to perform the patellar reflex? The arch reflex depends only on the inte
Valuation of biological resources includes the process of deriving a monetary value to the things that are not sold in the market. Examples are the value given to fuelwood gathere
Substrates are reagent molecules upon which enzymes act. The enzyme has spatial binding sites for the attachment of its substrate. These sites are known as activation centers of
How can coacervates be formed of phospholipids or polypeptides? Phospholipids are amphipathic molecules, i.e., they present a polar portion and a nonpolar portion. In contact w
morphological characterstics of e histolytica
What type of compound is the major metabolic waste of Porifera? Why is it important for the organism to get rid of this compound?
What is the water cycle? The water cycle represents the circulation and recycling of water in nature. Liquid water on the planet surface is heated by the sun and turns into
On a given microscope, the numerical aperture of the objective is 1.5. The microscope is provided with a filter that selects a wavelength of 500 nm. What is the limit of resolution
What is bicuspid aortic? Bicuspid aortic valve is the most common form of CHD seen in adults. Isolated bicuspid aortic valves may be stenotic or non-stenotic to start with. T
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd