evaluation of salinity tolerance at emergence and seedling stages of amaranthus retrofelexus l. under control environmental

salinity is one of the environmental factors that have a critical influence on the plant emergence and plant growth and establishment. the determination of salinity tolerance threshold is a useful criterion to choose soil and irrigation water for cultivation of halophytes. in order to determine salinity tolerance threshold in amaranthus retrofelexus, an experiment was performed in greenhouse based on a complete randomized block design with four replications in two stages. in first stage, the experiment was performed with salinity levels of 0, 10, 20, 30 and 40 dsm-1 and emergence percentage in salinity levels of 0 and 10 dsm-1 was 90 and 57%, respectively. in order to determine the full – scale of salinity tolerance threshold amaranthus retrofelexus, the second experiment was conducted. at this second stages, treatment were different levels of salinity equal to 10, 12, 14, 16 and 18 dsm-1 nacl. amaranthus retrofelexus seedling were able to emerge up to the salinity of 14 dsm-1 nacl. generally, with increasing the levels of salinity, the seedling emergence percentage was decreased. according to result, salinity tolerance threshold for seedling emergence and performance of amaranthus retrofelexus under controlled condition was 14 dsm-1