Plasticity in growth and patterns of dry matter distribution of two genotypes of Trifolium repens grown in different environments of neighbours

Replicates of two genotypes of Trifolium repens L., collected from a Poa pratensis dominated sward and a Dactylis glomerata dominated sward, respectively, were grown in swards composed of various proportions of P. pratensis and D. glomerata. These swards represented a range of environments of neighbours; an increasing proportion of P. pratensis was considered as an increasingly alien environment for individuals of T. repens collected from the D. glomerata dominated site, and vice-versa for the individuals from the P. pratensis dominated site. The individuals of T. repens were harvested on five occasions over a period of 27 months. Both genotypes responded to increasingly alien environments by producing more inflorescences and by distributing proportionately more dry matter to inflorescence production. Some evidence is also presented which suggests that allocation to stolons and inflorescences are alternatives and the balance of the trade off is dependent on the advantages of possibly producing new, better adapted offspring from seed, against the chances of a wandering stolon encountering a less hostile environment. Results are discussed in the context of environmental alienness, a major source of which is the different relative proportions of neighbours. The various genotypes of organisms which a relatively mobile plant species encounters are a major source of this environmental, or biotic, alienness.