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When growing in the field, plants are exposed to the effect of heavy metals as soon as the seed comes into contact with the soil solution. Therefore, we found important to study the effect of Cd and Ni on maize exposed to these heavy metals since sowing. The aim of this work was to examine which anatomical changes are induced by continuous intoxication of young maize root system with 0.1 mM Cd and Ni, thus modifying its growth and capacity for water and nutrient uptake. Concomitantly, the effect on concentration and distribution of Cd, Ni and some essential ions (Ca, Mg, Zn, Fe, Cu and Mn) was studied.Additional key words: continuous heavy metal intoxication, mineral nutrition, Zea mays.

The effect of various boron levels in the nutrient solution on the growth, boron and chlorophyll content, photosynthesis and chlorophyll fluorescence in the leaves of young sunflower (Helianthus annuus L.) plants was studied under greenhouse conditions. Deficiency of boron decreased the dry matter yield of the roots, shoots and leaves. The content of boron in all analyzed plant parts increased with the increase of boron levels in the nutrient solution, more so in the shoots than in the roots. Leaf area was reduced under boron deficiency as well as the content of chlorophyll in the leaves. The content of analyzed sugars was increased in boron deficient plants, glucose content exhibited the highest increase under boron deficiency.Boron deficiency appreciably decreased photosynthetic oxygen evolution by leaves, the apparent quantum yield and quantum efficiency of photosystem two electron transport. The diminished rate of photosynthesis in boron deficient sunflower leaves could be correlated to the diminished efficiency of electron transport and to the increased content of sugars in the leaves.

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