Physiological integration improves mock strawberry [Duchesnea indica (Andr.) Focke] uniformity under heterogeneous saline conditions

Abstract

Mock strawberry is a valuable ground cover species that has a strong adaptability and high ornamental values. Urban landscape soils are typically heterogeneous and of low fertility. We hypothesized that mock strawberry can grow uniformly in soils with patchy saline conditions because of physiological integration as a clonal species. The objective of this study was to investigate if connected mock strawberry plantlets (ramets) showed coordinated responses to heterogeneous salinity. Paired proximal and distal ramets, either connected or disconnected, were subjected to salinity treatment by supplying the proximal ramets with NaCl solutions in 0, 100, 200, and 300 mmol L−1 every other day, while the distal plantlets were watered with distilled water. The results showed that connected proximal ramets were less stressed than the disconnected proximal ramets as shown in leaf relative water content, chlorophyll content, and proline content. The total root length of connected ramets were longer than the disconnected ones. The root biomass was also greater in the connected proximal ramets than the disconnected ramets at an earlier stage of salt treatment and under lower salt concentrations compared to other measurements. Physiological integration also alleviated leaf discoloration in the connected ramets. Ultimately, the uniformity of shoot biomass among the connected ramets suggested that physiological integration played an important role in mock strawberry as a ground cover species under heterogeneous saline conditions.