Data_Sheet_1_Ion absorption, distribution and salt tolerance threshold of three willow species under salt stress.docx

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.

为探究三种柳树幼苗（Salix matsudana、Salix gordejevii、Salix linearistipularis）的响应机制及耐盐阈值，本研究在无土栽培条件下，对不同盐浓度（对照CK、171、342、513和684 mm）及处理时间（1、3、5、8、11和15天）下，对盐离子的吸收、运输及分布进行了研究。Salix linearistipularis在维持其表观形态方面的能力最弱，而Salix matsudana则表现出最强的能力。三种植物均具有一定的Na+截留能力，其中Salix matsudana和Salix gordejevii的截留能力高于Salix linearistipularis。Salix linearistipularis的叶片SAK,Na含量高于Salix matsudana和Salix gordejevii。叶片的选择能力最强，而根系统的选择能力在Salix linearistipularis中最低。长期低盐浓度及短期高盐浓度均可增加根、叶的盐分含量。在长期高盐胁迫环境中，Salix matsudana的生长更为稳定，而在短期高盐胁迫环境中，Salix gordejevii的生长亦能保持稳定。然而，由于Salix linearistipularis对盐胁迫的敏感性较高，故更适宜作为指示植物进行种植。Salix matsudana和Salix gordejevii的根部Na+含量为34.21 mg/g，达到最大的根保留容量。一旦根部Na+含量积累超过此值，根的排斥能力将被突破，选择性离子吸收能力将迅速减弱，进而容易导致植物死亡。