Variations in achene traits, germination, and seedling growth of Pluchea dioscoridis (L.) DC. as affected by maternal climatic aridity [electronic resource]

Includes bibliographic reference

The collection and germination of seeds for conspecific population distributedalong climatic gradients can elucidate maternal environmental effects on achene traits, germination, and seedling establishment and fitness. The current study explored this approach for the natural populations of Pluchea dioscoridis (L.) DC. (Asteraceae), which grows over a wide range of climatic regions in Egypt (Mediterranean, semiarid, and arid). The arid region showed the smallest achene size and pappus length, whereas the achene size of the Mediterranean region was >36% and >27% larger than those of arid and semiarid regions, respectively. In general, seed viability decreased with aridity and ranged from 41.96% in semiarid to 9.32% in arid regions. Achenes from the three maternal climatic regions began germinating at approximately the same time, but the germination rates proceeded differently. The achene germination percentage ranged from 10% in arid regions to 33.54% in semiarid regions. The study showed a significant effect of maternal climatic aridity on achene traits, germination rate, and final germination percentage of P. dioscoridis. However, the survival rate in the three climatic regions became constant after 130 days of sowing. The results demonstrated how such widespread species acquire multiple maternal traits and mechanisms to optimize their adaptation, regeneration, and conservation of populations in stressful environments. However, further studies are required to demonstrate the phenotypic plasticity, reproductive efforts, and mechanism of dormancy loss of P. dioscoridis under different natural climatic conditions.
Keywords: Achene traits, Climatic gradient, Dormancy, Fitness, Germination, Seed viability.

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