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Experimental evidence for negative turgor pressure in small leaf cells of Robinia pseudoacacia L versus large cells of Metasequoia glyptostroboides Hu et W.C. Cheng. 2. Höfler diagrams below the volume of zero turgor and the theoretical implication for pressure‐volume curves of living cells
Author(s) -
Yang Dongmei,
Li Junhui,
Ding Yiting,
Tyree Melvin T.
Publication year - 2017
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.12860
Subject(s) - robinia , turgor pressure , botany , chemistry , horticulture , biology
Abstract The physiological advantages of negative turgor pressure, P t , in leaf cells are water saving and homeostasis of reactants. This paper advances methods for detecting the occurrence of negative P t in leaves. Biomechanical models of pressure‐volume (PV) curves predict that negative P t does not change the linearity of PV curve plots of inverse balance pressure, P B , versus relative water loss, but it does predict changes in either the y ‐intercept or the x ‐intercept of the plots depending on where cell collapse occurs in the P B domain because of negative P t . PV curve analysis of Robinia leaves revealed a shift in the x ‐intercept ( x ‐axis is relative water loss) of PV curves, caused by negative P t of palisade cells. The low x ‐intercept of the PV curve was explained by the non‐collapse of palisade cells in Robinia in the P B domain. Non‐collapse means that P t smoothly falls from positive to negative values with decreasing cell volume without a dramatic change in slope. The magnitude of negative turgor in non‐collapsing living cells was as low as −1.3 MPa and the relative volume of the non‐collapsing cell equaled 58% of the total leaf cell volume. This study adds to the growing evidence for negative P t .