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!
Pollen Tube Growth
There are significant differences in the fine structure of the tips of pollen tubes in compatible and incompatible pistils such as Lilium. Tubes growing in compatible pistils show deep embayment but no compartments (tubes in incompatible pistil have a compartmented cap). The compatible tubes undergo a transition from autotrophic nutrition (characterized by compartmented cap of golgi derived vesicles) to heterotrophic condition in which the secretion product from the stylar canals enter the pollen tubes through the deep embayments (tubes growing in incompatible pistils are unable to make this transition and thus are unable to continue growth due to the exhaustion of endogenous food reserves).
The pollen tube wall is composed mainly of polysaccharides. Since the pollen grain carries limited food reserves and a relatively large amount of new pollen wall material is synthesized during growth, it has been assumed that at least a part of the substance needed for pollen tube wall is contributed from the polysaccharides present in the pistil tissues. It has been shown that the polysaccharide component of the stigmatic exudate of L. longiflorum is incorporated into the cytoplasm of the growing pollen tubes and later a specific fraction of the incorporated exudate is extensively metabolised before being utilized for pollen tube wall biosynthesis.
Which of the following best describes why Okazaki fragments are not observed in PCR? A. DNA primase is used for the entire reaction therefore eliminating the production of Okaz
Describe 5 ways that a microorganisms directly or indirectly affects our lives.
what are the two main pollutants that contribute to acid rain
What is the formula for photosynthesis? H 2 O + 6CO 2 + Light Energy ----> C 6 H 12 O6+ 6O 2 6 molecules of water + 6 molecules of carbon dioxide --->1 molecule of glucose
Tetrasporic Embryo Sacs In this group neither of the meiotic divisions is accompanied by wall formation so that at the end of meiosis all the four haploid nuclei remain in a
Write the positive ion isoelectronic with neon The positive ion isoelectronic with neon must have 10 electrons and 11 protons, and thus must have an atomic number = 11. This i
Demonstration of immune responses and biomarkers: This may be done either on the basis of sero-conversion study on paired sera samples or by challenge (protection) test.
Define Harvard Step Test - aerobic capacity? In this test, the subject steps on and off an 18-inch platform at a rate of 30 times per minute. The evaluator records the subject'
Determine the term Anapsid ? The type of skull found in reptiles and seen today only in turtles. Behind the opening of the orbits the skull is solid and lacks temporal openings
I need help to study for my test and exam
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: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd