Ion absorption, distribution and salt tolerance threshold of three willow species under salt stress

Abstract

To investigate the response mechanism and salt tolerance threshold of three willow seedlings (Salix matsudana, Salix gordejevii, Salix linearistipularis), the absorption, transport and distribution of salt ions (Na+, K+, Ca2+) were studied under hydroponic conditions with different salt concentrations (CK, 171, 342, 513, and 684 mm) and treatment times (1, 3, 5, 8, 11, and 15 days). Salix linearistipularis has the weakest ability to maintain its apparent shape, while Salix matsudana has the strongest ability. The three plants have a certain Na+ interception ability, and the interception abilities of Salix matsudana and Salix gordejevii are higher than that of Salix linearistipularis. The leaf SAK,Na of Salix linearistipularis were higher than those of Salix matsudana and Salix gordejevii. The leaf selection ability was the highest, and the selection ability of the root system was the lowest in Salix linearistipularis. The long-term low salt concentration and the short-term high salt concentration can increase the root and leaf salinity. Salix matsudana grows more stably in a long-term high-salt stress environment, and Salix gordejevii grows stably in a short-term high-salt stress environment. However, Salix linearistipularis is more suitable for planting as an indicative plant because of its sensitivity to salt stress. The root Na+ content of Salix matsudana and Salix gordejevii was 34.21 mg/g, which was the maximum root retention capacity. Once the accumulation of Na+ content in roots exceeds this value, the rejection capacity of roots is broken through, and the selective ion absorption capacity will rapidly become weak, which easily leads to the death of plants.

Growth and Physiological Responses of Magnoliaceae to NaCl Stress

“…The absorption and transport of Na + , the main harmful ion to plants under NaCl stress, have always been the focus of research on salt stress. The capacity of a plant to limit Na + absorption, expel Na + from the root system, and prevent Na + from traveling to aboveground components is related to its ability to resist NaCl [ 46 , 47 ]. This study showed that the roots of Magnoliaceae could intercept Na + because the concentration of Na + was greater in roots under NaCl stress than in stems and leaves.…”

“…Plants block the entry of Na + into root cells at low NaCl concentrations by absorbing an excessive amount of K + . However, during severe NaCl stress, a significant amount of Na + enters cells because the plant membrane system breaks down, which lowers the K + level [ 46 , 49 ].…”

Osmoprotectants play a major role in the Portulaca oleracea resistance to high levels of salinity stress—insights from a metabolomics and proteomics integrated approach

“…With more Na + available in the saline treatments, the roots of the purslane plants were able to absorb it in greater quantity ( Table S2 ), confirming the premise that salt stress induces the concentration of Na + ions in the plant cells ( Borsai et al., 2020 ; Giménez et al., 2021 ; Kumar et al., 2021 ). Much of the absorbed sodium remained in the roots, and a small part was translocated to the aerial part of the plants ( Table S2 ), indicating that plants can reduce the damage of salt stress to aboveground tissues by regulating ion transport ( Ran et al., 2021 ; Ran et al., 2022 ). As for Cl − , the roots absorbed only a small part, which translocated to the aerial part of the plants.…”

“…For Yassin et al. (2019) and Ran et al. (2022) , low uptake of Na + and high uptake of K + mean salinity tolerance in higher plants.…”

Perspectives of phytohormones application to enhance salinity tolerance in plants

“…Although sodium cannot replace potassium in cellular functions, they both share a chemical resemblance that leads to potassium substitution by sodium. Na + and K + compete for root uptake sites and lower the K + and Ca 2+ intake during salinity stress [78]. Similarly, a significant decrease in K + absorption by plants is due to high Na + ions, regardless of whether Na + , chloride, or sulfate ions predominate in soil solutions [71].…”