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Exposure of roots of cucumber ( Cucumis sativus ) to low temperature severely reduces root pressure, hydraulic conductivity and active transport of nutrients
Author(s) -
Lee Seong Hee,
Singh Adya Prasad,
Chung Gap Chae,
Ahn Sung Ju,
Noh Eun Kyeung,
Steudle Ernst
Publication year - 2004
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.0031-9317.2004.00248.x
Subject(s) - cucumis , hydraulic conductivity , hydrostatic pressure , chemistry , conductivity , biophysics , membrane , horticulture , membrane permeability , osmotic pressure , ultrastructure , permeability (electromagnetism) , botany , biology , biochemistry , soil water , ecology , physics , thermodynamics
When root temperature dropped below 25°C, there was a sharp drop in the root pressure ( P r ) and hydraulic conductivity of excised roots ( Lp r ) of young cucumber ( Cucumis sativus L.) seedlings as measured with the root pressure probe. A detailed analysis of root hydraulics provided evidence for a larger reduction in the osmotic component of Lp r (77%) in comparison with the hydrostatic component (34%) in response to the exposure of the root system to 13°C. The activity of the plasma membrane H + ‐ATPase (EC 3.6.1.35) was reduced from 30 to 16 µmol Pi mg −1 protein h −1 upon exposure to 8°C for 1 day. Ultrastructural observations showed no evidence of loosening of the microstructure of endodermal cell walls in low temperature (LT)‐treated roots. It is concluded that the rapid drop in the P r in response to LT is largely caused by a reduction in the activity of the plasma membrane H + ‐ATPase rather than by loosening of the endodermal wall which would cause substantial solute losses. On the other hand, water permeability of root cell membrane at LT was related to changes in the activity (open/closed state) of water channels.