MD. Plant Biology, Mehregan University, Mahallat, Iran
This research was done in hydroponic environment in greenhouse at 3 stages (vegetative, flowering and full product) in 5 concentrations of Cd (0.1, 0.3, 0.9, 2.7, and 10 mm) for investigating physiological and biological effects. This study revealed that the increase of Cd concentration in understudy treatments causes the 49% reduction of sugar solution in 10 mm treatment. On the other hand, the gradual increase of Cd in cultivation caused the increase of starch, reduction of photosynthesis and blockage of carbon cycle enzymes. Furthermore, in heavy metal stress conditions of vegetative stage, Cd has negative effects on the protein amount of total treatments in p=0.01 signified level. When treatment starts, the amount of protein reduced until 33% in 0.1 mm concentration and this reduction can be seen also in other treatments. In contrast, in flowering stage the amount of protein is increased compared to the control. The study of different heavy metal concentration effects showed that plants are more sensitive to Cd (2-20 times more than others). The Generalized Linear Model variance test of aerial and underground plant organs traced the high level of Cd concentration in root in10 mm concentration. This increasing process in p=0.001 level also was seen in root, leaf, and fruit. The accumulation of Cd expressed high speed of Cd transport from the soil to upper organs of tomato, and this process reduced the amount of solvable sugar and protein.