GROWTH AND SURVIVAL AFTER COTYLEDON REMOVAL IN QUERCUS-ROBUR SEEDLINGS, GROWN IN DIFFERENT NATURAL SOIL TYPES

The effect of cotyledon removal on oak (Quercus robur L.) seedlings was studied in an experiment. In nature, acorns are dispersed by a predator, jay (Garrulus glandarius) which hoards acorns in autumn and hide them in the ground. These acorns may germinate in spring and after seedling establishment the birds locate young seedlings and remove and eat the cotyledons. Seedlings of oak were grown in field pots during two growing seasons. Cotyledons were removed from half of the plant material at the time of leafing in the first year. The seedlings were grown in six natural soils with different texture and nutrient status. Effects of soil type were more important than presence or absence of cotyledon on the growth of the oak seedlings. Survival of seedlings was unaffected by both soil type and cotyledon removal. There were no indications that the cotyledons were more important in nutrient-poor soils than in nutrient-rich soils. The conclusion was that oak seedling growth and survival are independent of their cotyledon at the time of the first leafing.