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Photosynthesis, leaf morphological characteristics, and shoot growth in response to severe light interception within tree canopy were investigated in ´Fuji´ and ´Jonagold´ apple (Malus domestica Borkh). Leaf area increased in the interior within canopy, but leaf weight and leaf thickness significantly decreased. Palisade cells formed 2 distinct layers in sun-grown leaves, but this arrangement was less well-defined in shade-grown leaves. Shoot diameter, length and internode length decreased in shade-grown leaves, while there was no difference in internode number between sun-grown and shade-grown leaves. Wood increment of shoot with canopy part attaching shade-grown leaves was very small, thus bark/wood ratio in shoot was significantly low in the interior of canopy in Fuji. Net photosynthesis was 18.9 ㎎ CO₂dm^(-2)·hr^(-1) in sun-grown leaves, but only half net photosynthesis was recorded in shade-grown leaves in both cultivars. Chlorophyll and mineral contents in leaves showed no significant difference between sun-grown and shade-grown leaves.
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