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.
An episode of diarrhoea can be acute (recent origin) or chronic (extended duration and repeated episodes) in nature. You may recall reading in the Food Microbiology ans Safety Cour
KREB CYCLE
Abscisic Acid (AbA) - Plant Growth Substances In 1961 Lice and Cams isolated a substance in crystalline form from mature cotton fruit. This substance stimulated the abscission
What are angiosperms, the flowering plants? What is the major feature that distinguishes them from the gymnosperms? Flowering plants have flowers and seeds (phanerogamic plants
Explain The ECG and cheast X- Ray? The ECG and Chest X-ray: If there is a suspicion of heart disease on basis of the history or physical examination an ECG and a chest X-ray
Explain Clinical dietitians Clinical dietitians, sometimes called therapeutic dietitians, are associated with health care institutes, hospitals and nursing homes. Depending on
Define Fats requirements of school children and adolescents? The linoleic acid requirements for school children and adolescents have been set at 3 en%. In terms of visible fats
Extra Cranial MAs Intrathoracic or intra-abdominal MAs are often asymptomatic until leakage or rupture occurs. Most extracranial MAs (ECMAs) will rupture if not excised. The app
The depicted food web is not complete, mainly because: a. The number of producers is less than the number of consumers. b. There are no decomposers. c. Only secondary co
Disorder of Adrenal Function: The disorders of adrenal function may lead to acute and chronic .adrenocortical insufficiency. Let us briefly describe each one as follows
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