Journal of Cell and Molecular Research

10-14

Authors: Asghar Mosleh Arany

This study examines the assumption that plant resistance to herbivory has fitness costs. To assess costs, a standard method was used for examining the significant negative genetic correlation between the resistance character and damage in the presence of herbivory and with fitness in the absence of herbivory. Seeds of five plants from four genotypes of Arabidopsis thaliana were sown under controlled conditions in a growth chamber. Half of the resulting two months-old rosettes were used for glucosinolate analysis and for herbivory assessment. The other half were transplanted into an enclosure in the natural habitat of this plant and their fitness (fruit number) were measured after harvesting the plants. Caterpillars from Spodoptera exigua were obtained from lab culture for herbivory assessment. Two second-instar caterpillars from S. exigua were placed on each of the rosettes. Larval weight of caterpillars was measured after 5 days. One hundred mg dry mass of leaves from 5 rosettes of each genotypes were used for HPLC analysis. There were genetic variations in types and quantities of glucosinolate between genotypes. The results from herbivory assessment showed that the larval weight of S. exigua fed on some genotypes was significantly lower than others, and therefore there was genetic variation in resistance to herbivore for A. thaliana genotypes. The statistical analysis showed that the larval weight of S. exigua was negatively correlated with the total glucosinolate concentration and with fruit number. Therefore, under the condition of this experiment, glucosinolates reduced damage by S. exigua and exhibited significant fitness costs.

29-34

Authors: Fatemeh Rostami and Ali Akbar Ehsanpour

Potato (Solanum tuberosum L.) auxiliary buds c.v. White Desiree were cultured in MS medium containing 0, 50, 100, 150 and 200 µM concentrations of silver thiosulfate (STS) under in vitro condition. After eight weeks, the effect of silver ions (Ag+) in the form of silver thiosulfate complex (STS), as an ethylene action inhibitor, on chlorophyll contents of leaves, ascorbate peroxidase, guaiacol peroxidase and catalase activities of roots and leaves were studied. Application of silver (STS) in culture medium increased chlorophyll content comparing to the control plants significantly. After treatments of potato plants with STS, ascorbate peroxidase and guaiacol peroxidase activities in roots were higher than shoots while catalase activity was higher in leaves than roots. However, increasing of STS concentration in the culture medium resulted in higher activities of antioxidant enzymes with some variations.

42-48

Authors: Maryam Shahrtash, Sasan Mohsenzadeh and Hasan Mohabatkar

In recent years, several plant species have been used as bioindicators, and several tests have been developed to evaluate the toxicity of the environmental contaminants. In this study, the root length and DNA band pattern of root tips in maize (Zea mays L.) seedlings were exposed at different concentration of cadmium pollutant (40 and 80 mg L−1). The results indicated that the root length of maize seedlings reduced with an increasing cadmium concentration. A random amplification of polymorphic DNA (RAPD) analysis from the extracted DNA was carried out using twenty three 10-base pair random primers. Eleven primers produced 72 bands between 221-3044 base pairs in gel electrophoresis. DNA damage became evident as the presence and/or absence of DNA fragments in the treated samples compared to the control groups. The number of disappearing bands in profiles increased from 33 at 40 mgL-1 of cadmium concentration to 45 after exposure to 80 mg L−1 cadmium concentration compared to total bands in control. Three new bands appeared in 40 mgL-1 of cadmium concentration but five in 80 mgL-1 of cadmium concentration. The results showed that RAPD analysis could be a useful tool for detection of genotoxic effects of cadmium toxicity on plants.