Germination ecology of three Plantago L. (Plantaginaceae) species living in a saline environment

ABSTRACT

The factors influencing the germination of Plantago coronopus L., Plantago crassifolia Forsskål and Plantago macrorrhiza Poiret, three species typical of saline environments, were analysed. Results show that the temperatures favouring germination lie between 10° and 25°C, and that the three species have an initial period of absolute dormancy at temperatures from 10 to 25°C as regards P. coronopus, and above 15°C for P. crassifolia and P. macrorrhiza. The length of the dormancy period increases as the temperature rises. Saline solutions greatly inhibit germination of P. coronopus, and to a lesser extent that of P. crassifolia and P. macrorrhiza: none of the species germinates in 0.2 M NaCl solutions. These data suggest that the presence of these species in saline environments depends less upon their tolerance to salt with respect to germination as on particular control mechanisms which permit them to carry out their life cycle when the ecological conditions are favourable

KEY WORDS:

• after-ripening time
• dormancy
• germinability
• Plantago
• seed