INTRAPOPULATION VARIATION IN SEED GERMINATION OF SIX ROCKROSE (CISTUS L.) SPECIES
Cistus seed populations have been regarded as possessing considerable heterogeneity in germination behaviour. The aims of this work were to study the germination characteristics under controlled conditions and variability of six Cistus species (C. albidus, C. crispus, C. ladanifer, C. laurifolius, C. populifolius and C. salvifolius). Seed collected from different individual plants of the same population were tested. Constant (10, 15, 20 and 25°C) and alternating 25/15°C temperature regimes with 16 h/8 h light/dark photoperiod conditions were used. Dry heat was used as presowing treatment to enhance germination. Large differences among different individual plants were detected for seed germination. Thus, final germination percentage of untreated seeds (control) varied from 1 to 42% for C. albidus; 2 to 14% for C. crispus; 1 to 55% for C. ladanifer; 5 to 72% for C. laurifolius; 2 to 24% for C. populifolius; and 0 to 36% for C. salvifolius. Therefore, the six Cistus species showed a physiological seed heterogeneity in germination behaviour. In all species studied, preheated seeds showed a significant increase in germination. Therefore, seed coat impermeability to water (physical dormancy) appears to be the main cause of seed dormancy present in these Cistus species. Additionally, in all Cistus species studied, significant differences among individual plants were found for seed weight. Seed water content and seed weight were not correlated with final germination percentage.
Pérez-García , F. and González-Benito, M.E. (2012). INTRAPOPULATION VARIATION IN SEED GERMINATION OF SIX ROCKROSE (CISTUS L.) SPECIES. Acta Hortic. 937, 379-384
Cistaceae, dry-heat pretreatment, morphological seed heterogeneity, physical dormancy, physiological seed heterogeneity, seed water content, seed weight