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.
Q. What is Atrial Extrasystoles? Atrial premature beats often occur at lower workloads and have little significance. As exercise increases, they usually subside and may then re
Explain Ketoconazole It is now seldom used. The other azoles have fewer adverse effects and are usually preferred. Ketoconazole remains an option for treatment of infections w
Embryology: Embryology (from Greek words embryon which means unborn embryo and logia which means study) is a branch of science which deals with the development of an embryo starti
Explain about the Saponins? These are a diverse group of compounds commonly found in legumes like soybean, lentils, chickpeas, peanuts and alfalfa sprouts. They are also presen
Types of hypertension are as follows: Essential Hypertension is called essential when no apparent cause is suspected or detected. This accounts for almost 90 per cent of pati
Structural Function - Essential Elements The elements nitrogen, phosphorus and sulphur absorbed from the soil are essential components of amino acids and nucleotides. The othe
Origin of Cell Wall - The cell wall is product of cytoplasm. The cytoplasmic organelles such as endoplasmic reticulum, golgi apparatus play a very important role in the f
Assessment of new born The main purposes are: i) To identify normal characteristics in the neonate ii) To identify existing abnormalities, ii any iii) To carry
Osmosis and transpiration both play a part in the movement of water through a plant. Which of these two processes makes the greater contribution to the movement of water up the t
Define about the Glutathione peroxidases - Selenium? The role of selenium in the cytosolic enzyme, glutathione peroxidase (GSHPx), was first illustrated in 1973. Four selenium
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