Growth and Survival of Polygonum aviculare L. at a Brine-contaminated Site in Southeastern Ohio

Abstract

-Populations of Polygonum aviculare from low-salinity and high-salinity sites at a brine spill location in Ohio were studied to determine the effects of edaphic factors and intraspecific competition on seed germination, growth and survival. The effects of salinity and plant density on the growth, reproductive output and survival of P aviculare were investigated in the field. An additional study was performed in incubators to determine the effect of thermoperiod and salinity on seed germination. Seed germination was inhibited by increasing salinity and a thermoperiod of 35 Gday/25 Gnight. High summer temperatures and increased soil salinity may explain why viable seeds remained in the soil after the spring germination period in both highand low-salt plots. Soil salinity was consistently higher in the high-salinity plots than in the low-salinity plots during the growing season, while soil moisture levels did not differ (P < 0.05) between them. Low-salinity plots had higher plant densities and lower mortality than high-salinity plots. Survival was density-dependent in the low-salinity plots, but regulated primarily by salinity stress in the high-salinity plots. Biomass production was lower in the high-salinity than in low-salinity plots. Both intraspecific competition and salinity stress reduced growth and survival of P aviculare.