Chloride is beneficial for growth of the xerophyte Pugionium cornutum by enhancing osmotic adjustment capacity under salt and drought stresses

Abstract

<jats:title>Abstract</jats:title> <jats:p>Chloride (Cl–) is pervasive in saline soils, and research on its influence on plants has mainly focused on its role as an essential nutrient and its toxicity when excessive accumulation occurs. However, the possible functions of Cl– in plants adapting to abiotic stresses have not been well documented. Previous studies have shown that the salt tolerance of the xerophytic species Pugionium cornutum might be related to high Cl– accumulation. In this study, we investigated the Cl–-tolerant characteristics and possible physiological functions of Cl– in the salt tolerance and drought resistance of P. cornutum. We found that P. cornutum can accumulate a large amount of Cl– in its shoots, facilitating osmotic adjustment and turgor generation under saline conditions. Application of DIDS (4,4´-diisothiocyanostilbene-2,2´-disulfonic acid), a blocker of anion channels, significantly inhibited Cl– uptake, and decreased both the Cl– content and its contribution to leaf osmotic adjustment, resulting in the exacerbation of growth inhibition in response to NaCl. Unlike glycophytes, P. cornutum was able to maintain NO3– homeostasis in its shoots when large amounts of Cl– were absorbed and accumulated. The addition of NaCl mitigated the deleterious effects of osmotic stress on P. cornutum because Cl– accumulation elicited a strong osmotic adjustment capacity. These findings suggest that P. cornutum is a Cl–-tolerant species that can absorb and accumulate Cl– to improve growth under salt and drought stresses.</jats:p>

Chloride Changes Soil–Plant Water Relations in Potato (Solanum tuberosum L.)

“…Finally, the improved mesophyll diffusion conductance to CO 2 was able to compensate the lower stomatal conductance [28]. Similar findings were reported by Cui et al [29] recently in Pugionium cornutum-a xerophytic desert plant being widely distributed in Central Asia and belonging to the family of Brassicaceae. We assume that similar osmotic adjustments took place in potato in the present study, causing a decreased transpiration (Figure 1A) but without impairing photosynthesis and the partitioning of photoassimilates to the tubers as we could not find significant reductions in tuber yield or tuber dry matter (Figure 4A,B).…”

Chloride nutrition improves drought resistance by enhancing water deficit avoidance and tolerance mechanisms

“…This leads to the proposition that plants not only prevent deleterious effects of WD through the accumulation of Cl − , but additionally specifically promote Cl − accumulation in response to drought stress ( Table 1 ). Previous observations correlated the accumulation of Cl − in leaves by water shortage with an improvement of the osmotic adjustment in a drought-resistant tomato cultivar ( Sánchez-Rodríguez et al , 2010 ), papaya ( Mahouachi et al , 2006 ), faba bean ( Shabala et al , 2000 ), and in the xerophytic Cl − -tolerant species Pugionium cornutum ( Cui et al , 2020 ).…”

Negative effects of long‐term exposure to salinity, drought, and combined stresses on halophyte Halogeton glomeratus

“…Plants react to reduce the tissue water potential to promote continued water influx and turgor maintenance. The osmotic adjustment could be accomplished by the accumulation of various osmotica, including inorganic ions as well as compatible solutes (Bai et al, 2019;Cui et al, 2020;. Na + toxicity is one of the main factors restricting plant growth exposed to saline environment as it leads to inhibition of photosynthesis and attenuation of metabolic activity (Kronzucker et al, 2013).…”