Effects of aeration and mineral supply on growth and mineral content of shoots and roots of apple trees (var. 'Golden Delicious' on M.IX).

One- or 2-year-old Golden Delicious apple trees on M.IX were grown either in a clay loam (in 60-1 containers) or in nutrient solution and the effects were studied of several aeration regimes. With the soil-grown trees these comprised flooding to various soil depths and for different times. With the trees grown in nutrient solution the aeration regimes compared were nutrient solution without aeration, tap water with or without aeration, and aerated nutrient solution (control). Shoot growth was depressed by high water tables, and that of trees receiving non-aerated nutrient solution or tap water (whether aerated or not) ceased after about 2 weeks. The root growth of trees receiving non-aerated nutrient solution or tap water was similarly depressed, but, by contrast, aerated tap water enhanced root growth. Details are given of treatment effects on the Ca, K, N and soluble sugar contents of the young and old leaves and of the young roots. The uptake of all mineral elements was similarly affected by lack of aeration, suggesting that the relationship between low Ca content and increased bitter pit incidence is not associated with differential absorption but rather with differential Ca distribution. (Abstract retrieved from CAB Abstracts by CABI’s permission