Effet des métaux lourds (cuivre et zinc) sur les paramètres chimiques, morphologiques et biométriques de la tomate (Lycopersicon esculentum. Mill)

Abstract

The objective of our work is to study separately the influence of copper and zinc as sulfates CuSO4 and ZnSO4 at doses of 0, 50 ,100 ,200 ,300 ,400 ,500 ,1000 et 2000ppm, on the chemical, morphological and biometrical behavior of tomato plants Lycopersicon esculentum Mill. Copper and zinc application was carried out during all the physiologic cycle of the plant. This study permitted to extract the following points: The study of the heavy metals effect (Copper and Zinc) on plant height revealed that they exert growth stimulation up to doses between 300 and 400ppm, but an application over these levels induces growth relenting of plant height in case of copper and cause the death in case of zinc. Roots elongation is very sensitive to copper augmentation and decreased at doses 300, 400 and 500ppm, therefore zinc at concentration 200ppm enhanced root length elaboration. The action of the two metals is a fertilizer up to the dose of 200ppm, ameliorating the fresh and the dry matter production particularly that of shoot. Over this dose the effect of Cu and Zn became negative and detrimental especially on the roots or also cause the death. Concerning chemical parameters, the two metals accumulation in everyone of plant shoot and root increased in rate and measure that their concentration increased in the substratum. It can be said else that Cu application is an antagonist of P and K absorption at any dose. In contrast, Zn application affected positively the K and P content and vise to ameliorate their absorption. The response of fruits production by plants under cupric application manifested first by elevation of the number product at dose 200ppm, and then there was a yield failure allowed by 500ppm copper treatment. At inverse, fruits weight did not vary significantly by copper or zinc presence.