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.
How could knowledge of a pest organism's tolerance limits be used in pest control? Pesticides could be developed that make those limits narrower, environmental conditions could
Q. What is the anatomical reason for the left bronchus to be more elevated than the right bronchus? Why in most cases of aspiration of foreign material by children is the object fo
Define Briefly the Enzymatic Proteins? The most varied and very highly specialized proteins are those along with catalytic activity - the enzymes. Virtually all the chemical re
What is Glycolysis in Cell Metabolism? Glycolysis : is the process that breaks down glucose into pyruvate and energy. Glycolysis does not require the presence of oxygen and
Domesticated animals provide much of the world's meat products today, but wildlife still constitutes to be an imp ortant source of food of many rural communities. The International
Define Methods for Studying the Nutrient Requirements? 1) Population survey of nutrient intakes of healthy individuals is one method of estimating nutrient requirements. The av
Myoglobin We can build up the structure of haemoglobin by considering a single unit or monomeric form caned myoglobin. This consists of a single polypeptide chain the globin i
Autogamy - Patterns of Sexual Reproduction It is known to take place in many ciliate protozoans including Paramecium. Autogamy involves same nuclear behavior like in conjugati
Q. What is the deplasmolysis of plant cells? The plant cell when placed under hypertonic medium loses a great quantity of water and its cell membrane detaches from the cell wal
Explain Properties of Natural fats and oils Natural fats and oils vary widely in their physical properties even though they are composed of the same or similar fatty acids. Th
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