In this study, the antimicrobial activities of methanolic extracts and latex of some Euphorbia species used for medical purposes in Turkey were investigated.

Effects of cadmium chloride (CdCl 2 H 2 O) on the content of chlorophyll (a'/b), chlorophyll a/b ratio, proline, protein and abscisic acid in sunflower (Helianthus annuus L.) seedlings has been investigated. One-week-old seedlings were grown at cadmium concentration of 0.05, 0.07 and 0.09 mM for ten days in Hoagland's solution. Elevated cadmium levels increased the abscisic acid contents in roots, shoots and leaves of seedlings. An increase of proline in the leaves of seedlings exposed to cadmium occurred, as well as a decrease of chlorophyll (a'/b) and total protein (p B/0.05 or p B/0.01) contents. Thus cadmium levels at certain critical points negatively affect seedling growth.

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The eff ects of nickel, cobalt, chromium and zinc on the content of vitamins A, E and C, malondialdehyde (MDA), chlorophyll and carotenoids were investigated in bean seedlings (Phaseolus vulgaris L.) grown in Hoagland solution Control and heavy metal-treated plants were grown for ten days in Hoagland solution. Vitamin A, E, and C content were measured in primary leaves by high performance liquid chromatographic (HPLC). MDA, chlorophyll and carotenoids were measured in leaves by spectrophotometer. In heavy metal treated plants, the levels of MDA, vitamins A, E and C and carotenoids signifi cantly increased, while chlorophyll content decreased in leaves of seedlings. The results indicate that heavy metals caused an oxidative stress in bean plants. The strongest eff ect on vitamins A, E and C, MDA, chlorophyll and carotenoids was found in plants exposed to nickel, followed by the sequence cobalt > chromium> zinc.

In this research the effects of STEM applications, which are aimed to support the integrated teaching knowledge of pre-service science teachers on the problem solving skills of pre-service science teachers were examined. The research was carried out in scope of the mixed method design of convergent parallel design. The research was conducted with pre-service science teachers of experimental group (n=31) and control group (n=31) who were studying at Fırat University. STEM applications including Algodoo were carried out with the pre-service teachers in the experimental group for one term. The data of the research were collected through the problem solving inventory test (PSIT), prospects diaries during the process of the pre-service science teachers in the experiment group. Quantitative data were analyzed using unpaired samples t-test. Statistically significant differences were found in favor of the experimental group when the PSIT post-test scores of the pre-service teachers in the experimental and control groups were analyzed. They said that STEM education is necessary and important for them, much better products arise as a result of gathering different disciplines, but integration of four disciplines is not easy.