Accumulation of heavy metals in crop plants from Gaza Strip, Palestine and study of the physiological parameters of spinach plants

Measurements of Pb, Zn, Cd and Fe concentrations in the soils and accumulation in edible parts of several crop plants (spinach, wheat, strawberry, carrot, onion, squash, cabbage, potato, faba bean and cucumber) grown in three sites of the northern area of Gaza Strip, Palestine, revealed: (1) Concentrations of metals were in normal range in soil, except for lead concentrations which in some samples were higher, especially in the sites of Al-Monttar and Gaza city center. (2) Accumulation of heavy metals by the crop plants was within normal ranges, except for lead concentration which exceeded normal ranges, yet not reaching toxic levels in all plants but the onion bulb which reached toxic level. (3) Cadmium was concentrated at equal levels in different soil samples, while its accumulation in plant samples was very low and sometimes was not detectable. Measurements of physiological attributes of spinach plants revealed: (1) Growth characters such as root length, shoot height, fresh and dry weights of shoot and root were decreased with increasing Cd soil addition either alone or combined with Zn soil addition at all levels. (2) Plant pigments such as chlorophyll a, chlorophyll b and total carotenoids significantly decreased, with increasing Cd soil addition either alone or combined with Zn at all levels, except for chlorophyll a which increased with increasing Zn soil addition, with some exceptions. (3) Zn addition was highly correlated to growth characters, as well as when combined with Cd at different levels may be overcome the toxicity of Cd on growth characters, mineral concentrations and chlorophyll a content.