The Effect of the Plant Age and Growth Period on the Nutritional Substance,Chlorophyll and Steviol Glycoside Rates in Stevia (Stevia Rebaudiana Bertoni) Leaves

Stevia (Stevia rebaudiana Bertoni) is a perennial and subshrub herb of the Asteraceae family, which originates from South America. Stevia has long been used as a sweetener and herbal medicine throughout the world. The most important feature of stevia is its sweetness with zero calories. This natural feature of Stevia is of utmost importance to everyone, especially those with diabetes and those who diet. In this study, samples were taken from Stevia rebaudiana plants of different ages (2, 3 and 4 years) in different growth periods (H1: 1 July, H2: 1 August, H3: 1 September and H4: 1 October) and an evaluation was made on the nutritional content values, the chlorophyll and sugar rates found in these samples according to the age and growth period of the plant. It was determined that the age of the plant and the harvesting period had an effect on the macro-micro nutritional elements, and chlorophyll and steviol glycoside rates contained in the stevia plant. In addition, as a result of correlation analysis, significant correlations were determined between the parameters measured in the plant. The results of the study demonstrated that in the cultivation of stevia, the best values were obtained from plants that were 3 years old and harvested in July.     

Selection of promising chestnuts (<Emphasis Type="Italic">Castanea sativa</Emphasis>) among wild growing trees from southern Mediterranean region forests of Turkey

Turkey ranked third place in the world for chestnut production after China and South Korea and the country has unique chestnut forests including valuable and diverse chestnut genotypes. This study was conducted to select superior chestnut genotypes within seedling populations found in natural wild grown chestnut forest located in Isparta province in Turkey during 2010–2011 years. A total of 2500 wild grown chestnut trees were examined on the field first year and among them the most promising 22 genotypes were chosen according to relatively high yield capacity, earliness, tolerance to chestnut blight (Cryphonectria parasitica), ink disease (Phytopthora cambivora), and fruit quality characteristics. The selected 22 genotypes were evaluated for their detailed morphological, phenological and pomological traits in 2010 and 2011. According to average of 2 years, nut weight, the number of nut per kilogram, nut width, nut length, nut height and nut shell thickness of 22 promising genotypes ranged from 10.26 to 22.32 g, 97.47 to 44.80/kg, 26.80 to 42.47, 16.92 to 25.91, 27.74 to 39.73, and 0.26 to 1.01 mm, respectively. The ash, crude protein, and total fat content of kernels were between 0.85 to 1.94, 3.69 to 7.06 and 1.32 to 4.52, respectively. The genotypes were evaluated with weighted ranking method and the highest general quality score was observed in genotypes of IY17, IY01, IY42, IY43 and IY12.     

Changes in wettability of heat-treated wood due to artificial weathering

Effect of artificial weathering on the wettability of three heat-treated North American wood species (jack pine, aspen, and birch) is studied from the point of view of the structural and chemical changes taking place on the wood surface. Weathering increases wettability of all three heat-treated woods by water. Changes in wettability during artificial weathering differ according to heat treatment procedure and wood species and are likely due to combination of structural and chemical changes of the surfaces. Scanning electron microscopic analysis indicates that cracks form due to degradation taking place during weathering. As a result, water has easier entry into the cell wall, which consequently increases wettability. IR spectra suggest that the OH/CH₂ ratio for heat-treated specimens is inversely proportional to the contact angle regardless of the type of wood species. The presence of cellulose-rich layer on wood surface and increasing amount of amorphous cellulose transformed from crystallized cellulose due to weathering result in increase in hydroxyl; consequently, it increases heat-treated wood wettability.     

Identification of nitrate leaching hot spots in a large area with contrasting soil texture and management

Identification of nitrate (NO₃) leaching hot spots is important in mitigating environmental effect of NO₃. Once identified, the hot spots can be further analyzed in detail for evaluating appropriate alternative management techniques to reduce impact of nitrate on groundwater. This study was conducted to identify NO₃ leaching hot spots in an approximately 36,000 ha area in Serik plain, which is used intensively for agriculture in the Antalya region of Southern Turkey. Geo-referenced water samples were taken from 161 wells and from the representative soils around the wells during the period from late May to early June of 2009. The data were analyzed by classical statistics and geostatistics. Both soil and groundwater NO₃-N concentrations demonstrated a considerably high variation, with a mean of 10.2 mg kg⁻¹ and 2.1 mg L⁻¹ NO₃-N for soil and groundwater, respectively. The NO₃-N concentrations ranged from 0.01 to 102.5 mg L⁻¹ in well waters and from 1.89 to 106.4 mg kg⁻¹ in soils. Nitrate leaching was spatially dependent in the study area. Six hot spots were identified in the plain, and in general, the hot spots coincided with high water table, high sand content, and irrigated wheat and cotton. The adverse effects of NO₃ can be mitigated by switching the surface and furrow irrigation methods to sprinkler irrigation, which results in a more efficient N and water use. Computer models such as NLEAP can be used to analyze alternative management practices together with soil, aquifer, and climate characteristics to determine a set of management alternatives to mitigate NO₃ effect in these hot spot areas.     

Performance and ileal histomorphology of rats treated with humic acid preparations

As humic acid (HA) substances have antiphlogistic, adsorptive, antitoxic and antimicrobial properties, we studied the possible effects of Farmagülat?r, an organic HA preparation, on the rat performance, nutrient retention, ileal histomorphology and hydroxyproline (HP) content of the ileum in two experiments. In experiment 1, 48 male Wistar albino rats were allotted to three dietary treatments. Each was randomly assigned to four cages, each with four rats. The treatments consisted of a control diet (C) with no addition of Farmagülator Dry or Liquid, a treatment with addition of 2.5 g/kg Farmagülator Dry (FDry) and a control diet containing no FDry, but the rats had 3.5 ml/l Farmagülator Liquid in drinking water (FLiquid). The experiment lasted for 20 days. Changes in live weight were recorded at days 10 and 20 of the experiment. At the end of 20 days, all rats were killed to collect samples of intestinal tissues for the measurements of histological parameters. In experiment 2, 30 rats weaned at 21 days of age were divided into three groups, each with 10 rats, and individually caged in metabolism cages for 10 days. The above three treatments were randomly assigned to rats for 10 days to record body weight and feed intake. During the last 5 days, faecal outputs were collected to determine the dry matter and nitrogen retention. In experiment 1, FDry and FLiquid rats significantly (p<0.05) gained more live weight than the control rats. Improved weight gain with HA preparations was found to be highly associated with a high epithelial surface area as there were significantly (p<0.05) longer villi heights and crypt depths and increased HP contents of ileum in the HA treated rats compared with the control rats. Although the increased weight gain in FLiquid rats did not significantly (p>0.05) differ from the control rats in experiment 2 in contrast to the result in experiment 1, the FDry rats significantly (p < 0.05) gained more weight than the control rats. This was primarily found to be associated with significantly (p<0.05) increased feed intake and nitrogen retention in FDry rats compared with the control rats. It can be concluded that HA preparations, especially FDry, caused increased weight gain in rats as overall of two experiments. The improved weight gain only by FDry preparation was associated with increased ileal epithelial mass, increased feed intake, improved feed : gain ratio and increased nitrogen retention in rats.