Sodium Chloride Transport in the Stolons of Zoysia matrella in a Heterogeneous Saline Environment

Abstract

Zoysia matrella Merr. can tolerate salt. However, nothing is known about NaCl transport in the stolon between ramets. We examined how much NaCl is transported to other ramets via the stolons to enhance understanding of the salt tolerance mechanisms from the perspective of physiological integration. In this study, interconnected clonal stolon ramets were grown in three separate pots (basal [BR], intermediate [IR], and apical ramets [AR]), such that the stolons were not touching the soil (SNTS). The study was conducted in two experimental plots: (A) all ramets were irrigated with tap water (control), and (B) IR was irrigated with NaCl solution, while BR and AR were irrigated with tap water (NaCl application in IR). For the IR irrigated with NaCl solution, the leaves, stolons, and roots had higher Na+ and Cl− concentrations than those of the ramets irrigated with tap water. In comparisons of BR and AR, there were no significant differences in the Na+ or Cl− contents of each part of the ramet, compared with plants irrigated with tap water. In the SNTS irrigated with NaCl solution, the leaves and stolons contained more Na+ and Cl− than those irrigated with tap water. From these results, it was found that until a stolon node touches the ground and develops roots, Na+ and Cl− are transported through the stolon. However, for interconnected ramets under heterogeneous saline conditions, there are two hypotheses: NaCl might be diluted with water in BR and AR, or NaCl is not transported from IR to either BR or AR after ramets are established.