Quantifying Key Points of Hydraulic Vulnerability Curves From Drought-Rewatering Experiment Using Differential Method

Abstract

Precise and accurate estimation of key hydraulic points of plants is conducive to mastering the hydraulic status of plants under drought stress. This is crucial to grasping the hydraulic status before the dieback period to predict and prevent forest mortality. We tested three key points and compared the experimental results to the calculated results by applying two methods. Saplings (n = 180) of Robinia pseudoacacia L. were separated into nine treatments according to the duration of the drought and rewatering. We established the hydraulic vulnerability curve and measured the stem water potential and loss of conductivity to determine the key points. We then compared the differences between the calculated [differential method (DM) and traditional method (TM)] and experimental results to identify the validity of the calculation method. From the drought-rewatering experiment, the calculated results from the DM can be an accurate estimation of the experimental results, whereas the TM overestimated them. Our results defined the hydraulic status of each period of plants. By combining the experimental and calculated results, we divided the hydraulic vulnerability curve into four parts. This will generate more comprehensive and accurate methods for future research.

Leaf Functional Traits of Two Species Affected by Nitrogen Addition Rate and Period Not Nitrogen Compound Type in a Meadow Grassland

“…Plant functional traits are important for exploring the relationship between plants and the environment, which provide a basis for predicting the response of ecosystems in the context of global change ( Wright et al, 2010 ; Li et al, 2015 ; Liu et al, 2021b ). Previous studies have suggested that plant functional traits are key to elucidating the mechanisms that drive the responses of plant communities and ecosystems to resource addition ( McGill et al, 2006 ; Suding and Goldstein, 2008 ).…”

Physiological Responses of Robinia pseudoacacia and Quercus acutissima Seedlings to Repeated Drought-Rewatering Under Different Planting Methods

“…Gas-exchange characteristics were measured between 9:00 and 11:00 on sunny days. During the measurement, temperature, relative humidity, and CO 2 concentration inside the chamber were controlled at 28°C, 50%, and 400 ppm, respectively ( Wang et al, 2020 ; Liu et al, 2021 ).…”

“…where L is the length of the segment (m), Q m is the mass of the water per unit of time through a segment (kg s –1 ), S is the average cross-sectional area for both ends of the stem (m 2 ), and p is the intensity of the water pressure across the segment (MPa) ( Liu et al, 2021 ).…”

Plant Size Plays an Important Role in Plant Responses to Low Water Availability and Defoliation in Two Woody Leguminosae Species

“…Hydraulic conductivity (K h , mL mm h −1 Pa −1 ) was calculated as K h = Jv/( P/ L), where Jv is the flow rate through the segment (mL h −1 ) and P/ L is the pressure gradient across the segment (Pa mm −1 ). Stem-specific hydraulic conductivity (K s , mL mm −1 h −1 Pa −1 ) was calculated as the ratio of K h to stem cross sectional area (mm 2 ) according to Liu et al (2015Liu et al ( , 2021.…”