Proton-Potassium Pump Hypothesis

Proton-Potassium Pump Hypothesis:

Levitt in the year 1974 combined the points in Steward’s and Scarth’s hypothesis and provide a modified version of the mechanism of stomatal movement that was termed as the proton- potassium pump hypothesis.

According to this theory K+ ions are transported into the guard cells in the existence of light. The series of events occurring are:

a. Under the influence of light, protons build up by dissociation of malic acid move from cytoplasm to the chloroplasts of guard cells.

b. To counter the exit of protons, K+ ions enter the guard cells from the nearby mesophyll cells.

c. K+ ions react with the malate ions existed in the guard cells to form potassium malate.

d. Potassium malate causes rise in the osmotic potential of guard cells causing entry of water into the guard cells as an outcome of which the stoma opens.

e. At night the dissociation of potassium malate occurs and K+ ions exit out of guard cells causing loss of water from guard cells and therefore the stoma closes.

Fritz and Noggle in 1976 supported this theory and provide a scheme for opening of stomata.

1624_proton poasssium.jpg

This hypothesis is the widely accepted one as Levitt was capable to explain increase in K+ ion level during the day and the formation of organic acids such as malic acid with the unused CO2 existed in the guard cells.

Latest technology based Biology Online Tutoring Assistance

Tutors, at the www.tutorsglobe.com, take pledge to provide full satisfaction and assurance in Water transport homework help via online tutoring. Students are getting 100% satisfaction by online tutors across the globe. Here you can get homework help for Water transport, project ideas and tutorials. We provide email based Water transport homework help. You can join us to ask queries 24x7 with live, experienced and qualified online tutors specialized in Water transport. Through Online Tutoring, you would be able to complete your homework or assignments at your home. Tutors at the TutorsGlobe are committed to provide the best quality online tutoring assistance for Biology homework help and assignment help services. They use their experience, as they have solved thousands of the Biology assignments, which may help you to solve your complex issues of Water transport. TutorsGlobe assure for the best quality compliance to your homework. Compromise with quality is not in our dictionary. If we feel that we are not able to provide the homework help as per the deadline or given instruction by the student, we refund the money of the student without any delay.

©TutorsGlobe All rights reserved 2022-2023.