Factors influencing the saturated salt accelerated aging test in tomato and onion

摘要

The saturated salt accelerated aging (SSAA) test has been proposed to measure seed vigour of small-seeded crop species, however the test has not been standardized and is not described in the AOSA or ISTA Seed Vigour Testing handbooks. This study evaluated several testing variables and saturated salt solutions used in the SSAA test for tomato and onion seed lots. The SSAA procedure involves placing seed (tomato 0.6g; onion l.Og) on a fine-mesh tray suspended over 40mL of saturated salt solutions, which maintained the following tomato seed moistures from 6 to 72 hours of aging: potassium nitrate (KNO_3, 15%), potassium chloride (KC1, 12%), sodium chloride (NaCl, 11%), sodium nitrite (NaNO_2, 9%), and sodium bromide (NaBr, 8%). Counting (200 seeds) orweighing (tomato 0.6g; onion l.Og) seed samples for the SSAA test did not have a significant effect on final seed moisture, seed germination, or seedling growth rate following aging. Sealing the boxes for the SSAA test resulted in no significant difference in seed moisture between unsealed boxes after aging. When aging temperatures of 43, 45, 47, and 49 deg C were compared for tomato seed using saturated KNO_3 for 72 hours, the best seed vigour separation among seed lots occurred at 47 deg C. The SSAA method providing the best separation for onion seed lots was saturated NaCl for 72h at 45 deg C. The results indicate the SSAA test can be standardized to measure vigour in small-seeded vegetable crops and should be added to the AOSA and ISTA seed vigourtesting handbooks.