Implications of physiological integration of stolon interconnected plants for salinity management in soilless strawberry production

Salinity can be a greater problem in shallow soilless media than in field soils because of the small root zone volume that commonly occurs in such systems. Clonal integration (the capability of reciprocal resource translocation among interconnected plantlets through their shared stolon) can alleviate salinity injury in strawberry (Fragaria x ananassa 'Albion'). Here we report the effect of clonal integration on leaf area, shoot and root dry biomass, net CO2 assimilation rate (AN), stomatal conductance (gs), intercellular CO2 (ci), transpiration (E), and instantaneous water use efficiency (WUE). Interconnected mother-daughter pairs of strawberry plants were grown in stirred solution culture under greenhouse conditions. Combinations with independent salinity levels on the mother and daughter side were imposed in a 4 × 3 complete randomized factorial design. Salinity levels of 1, 3, 6 and 9 dS m−1 were established by adding calcium chloride (CaCl2) and sodium chloride (NaCl) as needed to a 1 dS/m nutrient solution. Interconnected daughter plants grew in 0.2 CaSO4, or the 1 dS m−1 nutrient solution, or the same solution supplied to the mother plant. Values of all measured attributes decreased with salinity, with the exception of Ci, which increased at the highest salinity combination of mother and daughter plants. In contrasting salinity conditions, clonal integration ameliorated salt stress in mother plants through water transfer from daughter to mother plants. Interclonal resource translocation was mainly driven by the contrast in stress intensity between mother and daughter plants.