Comparative Longevity of Bryophyte Spores: Influence of Storage Conditions, Spore Maturity, and Plant Ecology

Bryophyte spores are known for long-distance dispersal and tolerance to adverse conditions, but their comparative longevity remains poorly understood. In this work we assessed whether moss spores are as long-lived as spores and seeds of other land plants. Spores of Funaria hygrometrica, Lewinskya acuminata, L. iberica and Ulota crispula were subjected to accelerated aging (AA: 45 °C, 60% relative humidity [RH]) and dry storage (15% RH, 20 °C) with periodic germination tests. Different maturity stages of F. hygrometrica were also included. Estimated initial viability constant (Ki), standard deviation of spore deaths' distribution in time (σ) and time for viability to drop to 50% (P₅₀) were determined by probit analysis from spore survival curves. Overall results showed short spore longevity for all species tested, regardless of storage conditions. P₅₀ ranged from 0.4 to 5.7 days (AA) and 58-150 days (dry storage), indicating faster deterioration than seeds or fern spores at the same storage conditions. In the case of F. hygrometrica, spores collected at peak maturity showed the longest longevity under both storage conditions. This study suggest that moss spores may be relatively short-lived, which could be related to their chlorophyllous nature. Ecological and conservation implications of this spore character are discussed.