Rapid Measurement of Drought Resistance in Plants Based on Electrophysiological Properties

ABSTRACT. Water loss in plant leaves causes mesophyll cells and their cell walls to shrink; thus, the cell volume becomes smaller. When leaf cells absorb water and expand, the cell volume becomes larger. The characteristic of water retention for cells is related to this expansion and contraction and is expressed as leaf tensity. In this study, leaves of Broussonetia papyrifera and Morus alba were used to examine the physiological capacitance, water potential, minimal fluorescence, and maximal photochemical efficiency of photosystem II (PS II) before and after water loss. The measured physiological capacitance value and water potential were used to calculate the relative tensity of leaves. The values of relative tensity in B. papyrifera and M. alba were 3.965 and 2.624, respectively. By measuring the minimum chlorophyll fluorescence and maximal photochemical efficiency of PS II in the leaves, the relative minimal fluorescence and maximal photochemical efficiency were calculated; the measured minimal fluorescence and maximal photochemical efficiency were 5.496 and 7.640 for B. papyrifera and 6.577 and 5.359 for M. alba, respectively. Results of the two methods showed that the drought-resistance ability of B. papyrifera was greater than that of M. alba. The electrophysiological characteristics of the plants reflected their ability to resist drought.