Effects of podocarp extracts on lettuce seed germination and seedling growth

Abstract The effects of ethanol extracts from 16 of the 17 New Zealand species in the family Podo‐carpaceae on the germination of lettuce seeds and hypocotyl elongation are reported. Extracts of both juvenile and adult forms of Halocarpus kirkii and Halocarpus bidwillii were tested. Each extract was tested at three different levels: undiluted, and diluted × 10 ‐3 and × 10 ‐6 . The effects on germination and hypocotyl elongation were compared with solvent controls. None of the extracts showed promotion of hypocotyl elongation, so no gibberellin‐like activity was detected. The majority of the undiluted podocarp extracts inhibited both germination and hypocotyl elongation.