Contrasting Water Use Strategies of Tamarix ramosissima in Different Habitats in the Northwest of Loess Plateau, China

Abstract

As a species for ecological restoration in northern China, Tamarix ramosissima plays an important role in river protection, flood control, regional climate regulation, and landscape construction with vegetation. Two sampling sites were selected in the hillside and floodplain habitats along the Lanzhou City, and the xylems of T. ramosissima and potential water sources were collected, respectively. The Bayesian mixture model (MixSIAR) and soil water excess (SW-excess) were applied to analyze the relationship on different water pools and the utilization ratios of T. ramosissima to potential water sources in two habitats. The results showed that the slope and intercept of local meteoric water line (LMWL) in two habitats were smaller compared with the global meteoric water line (GMWL), which indicated the existence of drier climate and strong evaporation in the study area, especially in the hillside habitat. Except for the three months in hillside, the SW-excess of T. ramosissima were negative, which indicated that xylems of T. ramosissima are more depleted in δ2H than the soil water line. In growing seasons, the main water source in hillside habitat was deep soil water (80~150 cm) and the utilization ratio was 63 ± 17% for T. ramosissima, while the main water source in floodplain habitat was shallow soil water (0~30 cm), with a utilization ratio of 42.6 ± 19.2%, and the water sources were different in diverse months. T. ramosissima has a certain adaptation mechanism and water-use strategies in two habitats, and also an altered water uptake pattern in acquiring the more stable water. This study will provide a theoretical basis for plant water management in ecological environment protection in the Loess Plateau.

Responses of two dominant desert plant species to the changes in groundwater depth in hinterland natural oasis, Tarim Basin

“…euphratica faster than in T. ramosissima (Li, Si, Zhang, Gao, Luo, et al., 2019). To adapt to severe drought, T. ramosissima utilizes an optimal water absorption strategy and shifts the water source to obtain more stable moisture, which was beneficial to T. ramosissima to enhance hydraulic efficiency in the ecosystem (Su et al., 2020). However, P. euphratica improves the hydraulic conductance of branches with minor hydraulic limitation and diminishes branches with higher hydraulic limitation to avoid total loss of internal hydraulic regulation (Li, Si, Zhang, Gao, Wang, et al., 2019).…”

Revealing a significant isotopic offset between plant water and its sources using a global meta-analysis

“…Parameters and were calculated only for those campaigns where the linear relationship between 2 and 18 were significant (P < 0.05). In this step we discarded 133 campaigns, corresponding to nine studies (Geißler et al, 2019;Huang 185 and Zhang, 2015;Liu et al, 2011;Lovelock et al, 2017;Magh et al, 2020;McKeon et al, 2006;Saha et al, 2015;Su et al, 2020;Twining et al, 2006). Next, we estimated the difference in δ 2 H between each plant water sample and its corresponding soil water line (SW-excess) according to Eq (2) (Barbeta et al, 2019): where 2 and 18 denote the isotopic composition of individual plant water samples.…”

Untangling the Uncertainties in Plant Water Source Partitioning With Isotopes

“…Since the potential water source is more likely to be soil water than recent rainwater, the δ 2 H offset between xylem samples and their corresponding soil water lines is defined as SW-excess. Positive soil water excess values indicate that the xylem samples are more enriched in deuterium than the soil water line, while negative soil water excess values indicate that xylem samples are more depleted in deuterium than the soil water line (Su et al, 2020).…”