Selective restriction of root to shoot ion transport by cotyledon node zone in Kochia sieversiana may contribute to its tolerance to salt and alkali stresses

Abstract

This study is aimed to examine if cotyledon node zone may play a role in salt and/or alkali tolerance. Seedlings of halophyte plant Kochia sieversiana and glycophyte plant Lycopersicon esculintum Mill were treated with salt and alkali respectively, xylem sap was collected from above or below cotyledon node zone, and components and contents of inorganic ions in the sap were examined. When compared with that collected from below cotyledon node zone, xylem sap collected from above cotyledon node zone in K. sieversiana contains less Na⁺ under both salt and alkali stresses, and less chloride (Cl^–) under salt treatment. Both Na⁺ and Cl^– remain nearly the same in xylem sap collected from below and above cotyledon node zone in L. esculintum Mill. Cotyledon node zone in K. sieversiana selectively restricted ion transport under both salt and alkali stresses, which may represent a novel mechanism of salt and alkali resistance in halophyte plants.

Keywords:

• alkali tolerance
• cotyledon node zone
• ion transport
• salt tolerance
• xylem sap

Acknowledgment

This work was supported by grants from the National Natural Science Foundation of China (No. 31072078).

Disclosure statement

No potential conflict of interest was reported by the authors.