Premium
Is the signal from the mesophyll to the guard cells a vapour‐phase ion?
Author(s) -
MOTT KEITH A.,
BERG DAVID G.,
HUNT SEAN M.,
PEAK DAVID
Publication year - 2014
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12226
Subject(s) - guard cell , ion , epidermis (zoology) , hydronium , darkness , biophysics , phase change , chemistry , botany , photochemistry , analytical chemistry (journal) , biology , biochemistry , chromatography , physics , anatomy , organic chemistry , engineering physics
Previous studies have suggested that the red light and CO 2 responses of stomata are caused by a signal from the mesophyll to the guard cells. Experiments were conducted to test the idea that this signal is a vapour‐phase ion. Stomata in isolated epidermes of T radescantia pallida were found to respond to air ions created by an electrode that was positioned under the epidermes. Anthocyanins in the epidermes of this species were observed to change colour in response to these air ions, and this change in colour was attributed to changes in pH . A similar change in lower epidermal colour was observed in intact leaves upon illumination and with changes in CO 2 concentration. Based on the change in epidermal colour, the pH of the epidermis was estimated to be approximately 7.0 in darkness and 6.5 in the light. Stomata in isolated epidermes responded to pH when suspended over (but not in contact with) solutions of different pH . We speculate that stomatal responses to CO 2 and light are caused by vapour‐phase ions, possibly hydronium ions that change the pH of the epidermis.