Cover illustration: The cover photograph is a cross-section of a Norway spruce needle. Microscopic techniques were used to study the effects of ozone and drought on spruce needles. Drought-induced nutrient imbalance and memory-effects were noted in the conducting and mesophyll (photosynthesizing) tissues. Ozone affected the size and number of several cell organelles in the mesophyll. See Kivimenp et al., pp. 779–793.
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