PATTERNS OF RESOURCE-ALLOCATION IN FLESHY FRUITS OF 9 EUROPEAN TALL-SHRUB SPECIES

Within-fruit reproductive allocation was studied in the nine major fleshy-fruited shrub species of southern England. The partitioning of dry mass and nitrogen between flesh and stone, and between the fibrous coat of the stone and the embryocum-endosperm, was determined, together with the water proportion in each fraction. Mean allocation to flesh was 55% of the fruit dry mass. This did not vary with fruit size over an order of magnitude in total dry mass and a range of 1-26 in number of seeds per fruit. Nitrogen concentration was generally lower in the flesh than the stone (mean ratio 0.56:1), and there was a markedly smaller nitrogen allocation to flesh in larger fruits. Within the stone, the allocation of dry mass to fibrous coat varied from < 5% to 89%. Thick coats are characteristic of species showing delayed germination, and were found in five of the six species most often invading non-woody vegetation. The highest nitrogen concentrations in the embryo-cum-endosperm fraction were found in the species most often establishing in a grass turf. The fibrous coat generally had a very low nitrogen concentration compared with other fruit structures. The problems of interpreting the results are discussed in relation to possible phylogenetic inertia and only loose co-evolution between plants with fleshy fruits and their dispersers.