Establishment of Plantago lanceolata L. and Plantago major L. among grass : I. Significance of light for germination.

The influence of temperature, stratification, red/far-red ratio of the light (R/FR) and combinations of these factors on the germination of Plantago lanceolata and Plantago major ssp major have been investigated under controlled conditions. Only quantitative differences were found in the response of the species to the various environmental factors investigated except for germination in darkness. P. lanceolata germinated in darkness, the percentage depending on environmental factors and seed collection, whereas P. major seed swere found to have a virtually absolute light requirement. P. lanceolata germinated at lower temperatures and was less inhibited at a low R/FR than P. major. Pot experiments and a field experiment were carried out in order to study the influence of the presence of grass on germination and emergence. P. major was more inhibited than P. lanceolata when sown among grass and the presence of vegetation did not inhibit the germination of P. lanceolata in the field experiment. The latter could be ascribed to the dormancy alleviating effect of low winter temperatures to which the seeds had been subjected. The inhibition of emergence of P. major among grass could be explained by the light factor only, whereas in the case of P. lanceolata an additional factor must be involved.