To assess nickel-induced toxicity in plants, Zea mays seeds were germinated and cultured on nutrient solution with nickel concentrations of 0, 50, 100 and 200 μM for a period of two weeks. Its effects on the growth, Hill reaction and photosynthetic pigments content were then investigated. The fresh and dry weight of leaves and roots increased in 50 μM nickel, but decreased in 100 and 200 μM. The decline in length of root and shoot were observed by increasing nickel concentration. According to the results, root and shoot showed differential growth response to various nickel concentrations. Nickel concentrations up to 100 μM caused increase in the content of chlorophyll a, but resulted in decrease at 200 μM nickel. No significant changes in chlorophyll b and carotenoids contents were observed. The rate of Hill reaction, as the ability of chlorophyll a in the reaction center of PSII₆₈₀ to split water, decreased by increase in nickel concentration.

The tubers of Bongardia chrysogonum, belonging to to Podophyllaceae, are rich in alkaloids. In this study, total alkaloid content of the tubers of this plant in Naghadeh, Zanjan and Boukan were determined by spectrophotometeric method. In addition, the effects of soil characteristics such as total nitrogen, potassium, pH, soil texture and tubers nitrate levels on the plant total alkaloid content were measured. The results of the analyses indicated significant differences between the total alkaloid content of B.chrysogonum in these three regions. Moreover, the results showed significant differences among nitrates amounts of this plant in these habitats. The highest and lowest nitrate contents belong to Naghadeh and Boukan plants, respectively. The evaluation of soil samples of these three regions indicated that the texture of soil in Naghadeh is clay-loamy, in Zanjan it is silty- clay- loamy and in Boukan it is loamy- sandy. It was also discovered that increase in plant total alkaloid content depends on the increase of sand percentag in soil to some extent. The effect of soil pH on total alkaloid content turned out to be non-significant.