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

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• 作者：Dongmei Yang ; Junhui Li ; Yiting Ding and Melvin T. Tyree
• 刊名：Plant, Cell & Environment
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：40
• 期：3
• 页码：340-350
• 全文大小：1001K
• ISSN：1365-3040

文摘

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.