Seed ecology of the geophyte Conopodium majus (Apiaceae), indicator species of ancient woodland understories and oligotrophic meadows

C. Blandino, E. Fernández-Pascual, M. Marin, A. Vernet, H. W. Pritchard, R. Bekker
2018 Plant Biology  
Conopodium majus is a geophyte with pseudomonocotyly, distributed in Atlantic Europe. It is an indicator of two declining European habitats: ancient woodland understories and oligotrophic hay meadows. Attempts to reintroduce it by seed have been hindered by scarce seedling emergence and limited knowledge of its seed biology. • Micro-CT scanning was used to assess pseudomonocotyly. Embryo growth and germination were studied in the laboratory and the field, using dissection and image analysis.
more » ... image analysis. The effects of temperature, light, nitrate and GA 3 on germination were tested. Seed desiccation tolerance was investigated by storage at different RHs and by drying seeds at different stages of embryo growth. • Seeds possess morphological but not physiological dormancy. Embryo growth and germination were promoted by temperatures between 0 and 5°C, arrested above 10°C, and indifferent to alternating temperatures, light, nitrate and GA 3 . Pseudomonocotyly appears to result from cotyledon fusion. While seeds tolerated drying to 15% RH and storage for 1 year at 20°C, viability was lost when storage was at 60% RH. Seeds imbibed at 5°C for 84 days had significant internal embryo growth but were still able to tolerate drying to 15% RH. • Reproduction by seed in C. majus follows a strategy shared by geophytes adapted to deciduous temperate forests. The evolution of fused cotyledons may enable the radicle and the hypocotyl to reach deeper into the soil where a tuber can develop. The embryo is capable of growth within the seed at low temperatures so that germination is timed for early spring.
doi:10.1111/plb.12872 pmid:29972724 fatcat:qudwndybcrbtvaff63fxmr7is4