Electronic Resource
Oxford, UK
:
Blackwell Publishing Ltd
Plant, cell & environment
10 (1987), S. 0
ISSN:
1365-3040
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Abstract Stabilized microscopic preparations of an apoplastic fluorescent tracer, sulphorhodamine G (SR), have previously shown it confined to leaf cell walls. SR has a pK of 3.2, is dissociated at normal wall pH, and therefore does not enter cells. In transpiring soybean leaves, the SR showed a major internal water pathway in the walls of the paraveinal mesophyll (PVM), which has been implicated in the temporary storage of protein. Also the SR penetrated the PVM and bundle sheath cells, staining organelles and vacuoles, but not other leaf cells. This implies that sufficient SR is undissociated in these walls to allow penetration, and that the pH of the PVM walls is lower than that of most other cells. It is proposed that proton extrusion pumps are revealed by the low wall pH, and that these pumps are probably involved in collecting ammo acids from the transpiration stream.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/1365-3040.ep11602288
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