Germination rates of perilla (Perilla frutescens (L.) Britton) mericarps stored at 4 degrees C for 1-20 years.

Periodic update of stored seeds is indispensable for sustainable use and preservation of plant genetic resources, and performance of this task requires precise data on the relationship between storage period and the germination rate of seeds after long-term storage. In this study, germination rates of pure strains of perilla (Perilla frutescens (L.) Britton var. crispa) were investigated for three strains by using the mericarps stored for 1-20 years at 4 degrees C under dry conditions. The germination rates were fairly good (65-70%) for 5-8 years after harvest, but dropped to almost 0% for mericarps stored more than 9 years. Mericarps that did not germinate were analyzed for viability by using 2,3,5-triphenyltetrazolium chloride. For old mericarps (stored more than 9 years), the germination rates and seed viability did not correlate. Further study on days required for germination of mericarps harvested each year was derived from our observation record, suggesting that germination rates and longevity of mericarp life were increasingly influenced by individual difference as the storage period lengthened.