INFLUENCE OF ALUMINUM ON MINERAL NUTRIENT UPTAKE AND ACCUMULATION IN URTICA PILULIFERA L.

Pollutants can have detrimental effects on living organisms. They can cause toxicity, damaging cells, tissues and organs because of their high concentrations or activities. Plants provide a useful system for screening and monitoring environmental pollutants. Among pollutants, aluminum is considered as a primary growth limiting factor for plants resulting in decreased plant growth and development. Although considered to be a non-essential and highly toxic metal ion for growth and development, aluminum (Al) is easily absorbed by plants. Urticaceae family members have high nutrient requirements demonstrated by leaves containing high levels of calcium (Ca), iron (Fe), magnesium (Mg), and nitrogen (N). Urtica pilulifera is one of the important traditional medicinal plants in Turkey. In this study, U. pilulifera was used as a bioindicator to investigate the possible differences in the absorption and accumulation of mineral nutrients at different levels of the Al exposure and examine the mineral nutrition composition of U. pilulifera under Al stress. Also, some growth parameters (leaf-stem fresh and dry weights, root dry weights, stem lengths and leaf surface area) were investigated. U. pilulifera seedlings were grown for two months in growth-room conditions and watered with spiked Hoagland solution, which contained 0, 100, and 200 μM aluminium chloride (AlCl₃). It was observed that macro- and micro-nutritional status of roots and leaves was altered by Al exposure. The concentrations of some macro- and micronutrients were reduced while concentrations of others were increased by excess of Al. Some macro- and micronutrients were increased at low level of Al whereas reductions were observed at high level of Al, and vice versa. The patterns were dependent on the macro- or micronutrient and the plant part.     

Adsorption of olive leaf (Olea europaea L.) antioxidants on silk fibroin

The adsorption isotherms of oleuropein and rutin were evaluated at different temperatures, pH values, and solid/liquid ratios. The experimental data of adsorption isotherms were well fitted to a Langmuir model. The maximum adsorption capacities were determined as 108 mg of oleuropein/g of silk fibroin and 21 mg of rutin/g of silk fibroin. After adsorption of oleuropein and rutin, the antioxidant capacity of silk fibroin increased from 1.93 to 3.61 mmol of TEAC/g. Silk fibroin also gained antimicrobial activity against Staphylococcus aureus and Klebsiella pneumoniae after adsorption of olive leaf antioxidants. In a desorption process, 81% of rutin and 85% of oleuropein were removed from the adsorbent surface in 70% aqueous ethanol solution. Consequently, silk fibroin was found to be a promising biomaterial for the production of functional food or dietary supplements and for the purification of oleuropein and rutin from olive leaf extracts.