Seawater Stress Differentially Affects Germination, Growth, Photosynthesis, and Ion Concentration in Genotypes of Jerusalem Artichoke (Helianthus tuberosus L.)

Two Jerusalem artichoke (Helianthus tuberosus L.) genotypes, NY-1 and NY-7, were subjected to different seawater concentrations (0, 10, 20, 30, 40, and 50%) for various periods of time to determine the effects on seedling growth, ion content, and photosynthetic productivity in a greenhouse. Under different seawater concentrations, sprouting rates varied greatly among the genotypes. The differences in relative growth rate (RGR), leaf chlorophyll content, total leaf area (TLA), plant dry weight (PDW), photosynthetic rate (A), stomatal conductance (g (s)), and efficiency of the light harvesting of photosystem II (F (v) (') /F (m) (') ) were significant between NY-1 and NY-7 after 12 days of stress at 40 and 50% seawater. Seawater treatments resulted in the reduction of almost all the growth parameters and coincident increases of Na+ and Ca2+ concentrations in plant tissues. Our results indicate that there is great variability for seawater tolerance among H. tuberosus varieties, and that greater photosynthesis capacity, higher RGR, and relatively higher tissue Na+ accumulation at high seawater concentrations appears to be associated with seawater tolerance in H. tuberosus varieties.