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Plantago albicans L. (Plantaginaceae) grows in wastelands, slopes, and stony pastures, with dry and sun‐exposed soils. Its seeds produce a mucilaginous coat. The main aim of this study was to evaluate intraspecific variation of osmotic and salinity stress response and mucilage production in P. albicans seeds. The relationships between osmotic and salinity stress, germination characteristics, and mucilage expansion were studied in eight populations of P. albicans. Seeds were germinated in distilled water, 20% (w/v) polyethylene glycol 6000 (PEG), or 100 mM NaCl solutions. In most populations, PEG and NaCl reduced final germination. Also, germination was slowed more significantly under osmotic stress than under salinity, while mucilage expansion was more affected by salinity. Therefore, there was an inverse correlation between mucilage expansion and germination under salinity and osmotic stress. Seed populations with similar climatic parameters showed different germination response; however, a correlation was found between mucilage expansion and some climatic parameters. Seeds from drier habitats germinated faster under water stress and produced more mucilage under control and water stress than populations from more humid areas. [ABSTRACT FROM AUTHOR]

We studied the variability of germination, dormancy and viability loss of Hirschfeldia incana seeds in relation to seed size. Seeds were stored at 35°C under humid [75% relative humidity (RH)] or dry (33% RH) conditions. Seed germination and electrolyte leakage were evaluated periodically. Small seeds had lower longevity at humid or dry storage conditions (5 or 407 days, respectively) than large or intermediate seeds (7–9 or 536–727 days, respectively). Moreover, H. incana shows variability in seed dormancy related to seed size within a population, with small seeds having lower dormancy (13%) than intermediate (50%) or large seeds (72%). Dormancy was partially released after a short storage at 35°C and humid conditions. Under dry storage conditions, endogenous dormancy cycles were observed for over a year, and longer times of storage had a dormancy-breaking effect through dry after-ripening. Results suggest a dual strategy producing non-dormant seeds with low longevity that will germinate immediately after dispersal, and seeds with greater longevity that will delay germination. Membrane permeability increased linearly with ageing at both humid and dry storage (R 2 = 0.60). Small seeds showed greater conductivity than intermediate or large seeds (0.7, 0.4 or 0.3 mS g–1 dry weight, respectively, at the 80% germination). The conductivity test could be used to evaluate the quality of H. incana seeds and would allow us to identify dormant (non-germinating) seed lots as viable. However, the influence of storage conditions and variability within a seed population on seed longevity should be taken into account when evaluating seed quality. [ABSTRACT FROM AUTHOR]