Salinity Effects on Germination, Growth, Photosynthesis, and Ion Accumulation in Wild Miscanthus sinensis Anderss. Populations

The lignocellulosic crop Miscanthus spp. has been identified as a good candidate for biomass production. To satisfy the need for high yield and to avoid competition with food production by growing the crop in marginal areas, we studied the responses of M. sinensis to salinity. Effects of salt concentrations (0-360 mM NaCl) on seed germination, growth, photosynthesis, and shoot ion accumulation were examined. In the germination test of 17 accessions, high salt concentration inhibited seed germination in all accessions, while germination percentage varied significantly among the accessions. Two accessions showing variable salt tolerance, JM0119 (salt-tolerant) and JM0099 (salt-sensitive), were selected for a greenhouse study on plant dry weight, leaf chlorophyll content, total leaf area, tiller number, photosynthetic rate (A), stomatal conductance (g(s)), photosystem-II (PSII) operating efficiency (Delta F/F-m'), and shoot ion concentration during various lengths of time. The experiment was performed twice, but for most parameters, no significant differences between runs were observed. Salinity resulted in a reduction of plant growth. Photosynthetic rate and gs were adversely affected by all salt treatment levels, while Delta F/F-m' was not reduced until salt concentrations reached 120 mM NaCl. In contrast to the increases of shoot Na+ and Cl- concentrations, shoot K+ concentration declined in the presence of salt. Overall, this study revealed a great variability for salt tolerance in M. sinensis germplasm. The relative advantage of JM0119 over JM0099 under saline conditions was primarily associated with larger leaf area, a greater number of tillers, greater photosynthetic capacity, and restricted Na+ accumulation in shoots.