Variation in desert shrub foliar pH in relation to drought and salinity in Xinjiang, China

Abstract

Aim Foliar pH, an emerging plant functional trait, plays a key role in plant eco‐physiological processes. However, it remains unclear how foliar pH varies among plants with different preferences concerning soil salinity, and how it responds to drought stress in desert ecosystems. Location Xinjiang, northwestern China (40.24° N to 46.24° N, 80.66° E to 91.33° E). Methods We addressed variation in foliar pH in four desert shrub groups (i.e., euhalophytes, secretohalophytes, pseudohalophytes and glycophytes) with differing adaptive strategies to soil salinity in 29 sites in Xinjiang, China, and explored the effects of drought and saline stress on foliar pH variability. Results We found that average foliar pH of desert shrubs was 5.54 ± 0.02, higher than that of shrubs from humid areas. At the functional group level, euhalophytes (5.65 ± 0.03) and glycophytes (5.61 ± 0.04) had significantly higher foliar pH than secretohalophytes (5.47 ± 0.03) and pseudohalophytes (5.39 ± 0.05). Coverage‐weighted mean foliar pH of glycophytes‐dominated communities was significantly higher (5.80 ± 0.18) than those of the halophytes‐dominated communities (5.34 ± 0.07 ~ 5.49 ± 0.07). Only in pseudohalophytes there was a significant relationship between foliar pH and both drought stress (i.e., low soil water stress coefficient, aridity index, and mean annual precipitation) and saline stress (shown by high soil electrical conductivity and soil pH). In contrast, secretohalophytes displayed opposite or non‐significant relationships between foliar pH and drought and saline stress. Compared with salinity indicators, drought exerted a much larger impact on foliar pH, particularly in pseudohalophytes and secretohalophytes. Conclusions Our work documented a comprehensive analysis of foliar pH across halophyte and glycophyte shrub species, and found contrasting responses of foliar pH to drought and salinity in desert ecosystems, which can provide an alternative perspective for understanding the survival strategies of desert plants, and may also offer new insights into the population dynamics of desert shrub communities under global climate change.

Influence of surface water and groundwater on functional traits and trade-off strategies of oasis communities at the end of the Keriya River, China

“…The effects of soil moisture and salinity on the functional traits of communities in arid zones have been revealed by several studies (Gong et al, 2019;Luo et al, 2021). However, in the present study, soil factors were observed to assume a more mediatory role.…”

Liriodenine and Its Probable Role as an Osmolyte during Water Stress in Annona lutescens (Annonaceae)

“…In this study, the liriodenine alkaloid showed a slight up-regulation in the pH (Figure 4), so the presence of the alkaloid in the cell would not represent a pH imbalance, but rather would help to balance pH. It has been documented that the vacuolar pH is acidic under normal conditions (4.5-6.5; with variation depending on the species and conditions); however, during water stress, it decreases even further [53,54]. Matile [55], and Nowak and Selmar [56], state that alkaloids cross the tonoplast due to differences in pH between the vacuole and the cytoplasm.…”

“…In addition, the adjustment of cellular pH is important to maintain resistance to drought. The pH can be increased or decreased by the compounds present in cells, and the pH must be regulated to avoid affecting physiological processes [52,53]. In this study, the liriodenine alkaloid showed a slight up-regulation in the pH (Figure 4), so the presence of the alkaloid in the cell would not represent a pH imbalance, but rather would help to balance pH.…”

Soluble Biobased Substances in soil or Salicylic Acid on leaves affect the foliar pH and soil biovariability of Grapes-as explained by the NIR Spectroscopy of Litterbags and Teabags

“…This physiological measure is not usual in agronomy. A first comparative analysis on forty-nine Mediterranean species in different environmental conditions 43 was followed by observations on tree species located along 3300 km of a water gradient 44 and on desert species in China 45 . From a physiological point of view, a lowering of pH can be determined by a stress condition, be it water or heat 43 , such as an excess of UV-A, B 25 or by a reduction of the solar cycle over the years 46 .…”