Effect of Different Nitrogen Doses on Dry Matter Ratio,Chlorophyll and Macro/Micro Nutrient Content in Sweet Herb (Stevia rebaudiana Bertoni)

With this study, the effect of different nitrogen (N) doses applied to sweet herb (0, 50, 100, 150 and 200 N kg ha^?1) on the macro/micro nutrient element content, dry matter ratio and on the chlorophyll amount in the plant leaves is examined. The research was carried out in the research and trial field of Faculty of Agriculture Agronomy department, Akdeniz University, during the 2012–2013 growing season under field conditions for 2 years with four replications according to the randomized block trial design. Chlorophyll amounts were determined and the average was obtained with three readings from each leaf by a chlorophyll meter when the plants were in the beginning of flowering. Post-harvest macro and micro nutrient elements of the sweet herb were also investigated. According to the obtained data, while the highest chlorophyll and N amounts in the leaf for both the first and second years were determined as 46.97 SPAD (Minolta Corp, NJ, USA) and 1.34 N% 44.9 SPAD, 1.42 N%, respectively, under 200 kg ha^?1 N application, the lowest chlorophyll and N amounts were determined in the control group. In addition, N application in different doses for both years increased the phosphorus (P) and potassium (K) contents and increased the microelement contents, especially in the second year. At the same time, a correlation between the chlorophyll content in the plant leaves and the N amount was determined and a linear increase was observed in the chlorophyll amount with the increased green part.     

近16年来新疆耕地与人口变化相关分析

利用1990～2006年的统计数据,采用统计分析方法,建立了耕地与人口相关模型,在此基础上分析了近16年来新疆的耕地变化过程、地域分异特征、耕地与人口相关性变化趋势、以及不同地区耕地与乡村人口相关的区域差异。结果表明:近16年来新疆耕地面积呈现波动增加趋势,但增加速度缓慢,不同时段耕地年均递增率呈现高-低-高-低模式,耕地变化地域差异特征明显;利用2006年耕地与对应的乡村人口数据进行相关分析,发现耕地面积与乡村人口数之间存在着极显著的正相关关系;1990～2006年新疆耕地面积与乡村人口之间的相关性呈正相关,并达到了0.01水平的显著性,且不同地区乡村人口数与耕地面积之间的相关系数在不同时期差别较大;1990～2006年期间,人均耕地面积减少了0.0874hm2,年均递减率为1.46%,而劳耕密度呈现增长趋势,净增加0.1926人/hm2,年递增率为0.2754%,在不同时段人均耕地面积及劳耕密度的变化幅度及趋势不同。     

Boron-induced improvement in physiological,biochemical and growth attributes in sunflower (Helianthus annuus L.) exposed to terminal drought stress

Terminal drought stress (drought at reproductive growth stage) has been considered a severe environmental threat under changing climatic scenarios and undoubtedly inhibits sunflower production. A field study was conducted to explore the potential role of foliar applied boron (B) (0, 15, 30, 45 mg L^?1) at late growth periods of sunflower in alleviating the adversities of terminal drought stress (75, 64, 53 mm DI) grown from inflorescence emergence to maturity stages. The plant water relations such as leaf relative water content (RWC), water potential (Ψ_w), osmotic potential (Ψ_s), and turgor pressure (Ψ_p) were increased significantly with B foliar sprays while exposed to terminal drought stress. Foliar B application considerably improved the nitrogen and B concentrations in leaf and seed tissues, and also chlorophyll a and b pigments under terminal drought stress conditions. Drought-induced proline accumulation prevented the damages caused by drought stress, nevertheless, B foliar spray increased its contents. Compared to well-watered conditions, terminal drought stress substantially declined the growth performance in terms of reduced leaf area index (LAI), crop growth rate (CGR), net assimilation rate (NAR), and total dry matter (TDM) production; however, foliar B supply (30 mg L^?1) might be helpful for improving drought tolerance in sunflower with reduced growth losses.     

Cadmium (Cd) and Lead (Pb) Induced Changes in Growth,Some Biochemical Attributes,and Mineral Accumulation in Two Cultivars of Mung Bean [Vigna radiata (L.) Wilczek]

Addition of cadmium, lead, and cadmium + lead (Cd, Pb, and Cd+Pb) to growth medium leads to a reduction in seed germination, length, fresh and dry biomass of shoots and roots, total chlorophyll, chlorophyll a, chlorophyll b, and soluble proteins in plants. This study was undertaken on two mungbean cultivars (MN-92 and MN-98). Application of these metals in the growth medium reduced the bioabsorption of calcium (Ca), magnesium (Mg), and potassium (K). Concentrations of all the metals were greater in the roots than in the shoots except for K, which was greater in the shoots. Mungbean cultivar NM-98 performed better than NM-92 in response to heavy-metal toxicity. Overall, the metal-induced physiobiochemical changes resulted in reduced growth of both mungbean cultivars.     

Scratch deformations of poly (ether ether ketone) composites

The experimental results obtained from scratching a semicrystalline poly (ether ether ketone) surfaces, (PEEK), and its composites are presented in this paper. A semicrystalline PEEK and a carbon fiber oriented PEEK were scratched using conical indenters on a pendulum sclerometer. The carbon fiber oriented PEEK composites were scratched in the parallel, the orthogonal and the transverse direction to the fiber orientation. Subsequent deformations of the surfaces were assessed through subjective evaluation of the images obtained from a scanning electron microscope (SEM). The semicrystalline PEEK samples were found to be deformed by ductile ploughing and brittle deformation mechanism. In addition a fibrillation of the crystalline lamella of the polymer was also seen to be formed in case of severe brittle deformations. Fiber matrix debonding, matrix material debris formation, and fiber breakage were observed to be the dominant deformation mechanisms of the carbon fiber oriented composites. The scratch deformations of fiber oriented polymers were found to be highly dependent on fiber orientation angle relative to the scratching direction.     

Foliar calcium spray confers drought stress tolerance in maize via modulation of plant growth,water relations,proline content and hydrogen peroxide activity

Water and nutrient restrictions are the factors that limiting growth of maize in arid/semi-arid climate. Calcium (Ca²⁺) uptake is affected severely under drought stress (DS). The objectives of this study were to investigate the effects of DS and foliar applied Ca²⁺ on growth, physiological, biochemical, yield and grain-nutrient content in two maize cultivars i.e. drought-tolerantDekalb-6525 and drought-sensitive Yousafwala-hybrid. The study comprised of two phases; firstly the best rate of Ca²⁺ (20, 40 and 60 mg L?1) was evaluated. Secondly, optimized rate of Ca²⁺ (40 mg L?1) was used to assess physio-biochemical and yield responses of maize under DS. The applied DS caused significant reduction in maize growth, water-status, photosynthesis and grain nutrient contents. Foliar Ca²⁺ markedly improved plant growth, water-potential (18%), turgor-potential (75%), photosynthesis (45%), stomatal-conductance (47%), transpiration rate (43%) and accumulation of total soluble sugars (20%) along with decline in H2O2 content (23%) in both cultivars under DS. Furthermore, optimized rate of Ca²⁺ improved maize grain yield and quality under water-deficit conditions. Cultivar Dekalb-6525 presented significant response to Ca²⁺ over Yousafwala-hybrid. Results of the study surmise that foliar supply of Ca²⁺ is an effective approach to make plants vigorous to thrive under limited-water supply.     

Growth stage-based response of wheat (Triticum aestivum L.) to kinetin under water-deficit environment: pigments and gas exchange attributes

Plant growth regulator, kinetin, is known to modulate the key physiological processes under abiotic stresses in different crops. However, kinetin-mediated response at different growth stages of crop plants is lagging behind. Therefore, a field experiment was conducted to appraise the potential role of exogenously applied kinetin in alleviating the effects of water scarcity on wheat. Three levels of kinetin (0, 75, and 150 mg/L) were used either as seed treatment or foliar spray at the vegetative or the post-anthesis stage. Water deficit markedly reduced shoot fresh mass, plant chlorophyll level, flag leaf photosynthesis, stomatal conductance, and transpiration rate. Degradation of chlorophyll a was greater in plants subjected to post-anthesis water-deficit conditions. However, plants growing under continuous water-deficit conditions had significantly lower concentration of chlorophyll b than those treated with water scarcity at the post-anthesis stage or receiving normal irrigation. Inhibited photosynthesis of wheat in response to post-anthesis water-deficit conditions was largely due to non-stomatal factors. In contrast, stomatal factors were the main constraints for photosynthesis in plants growing under continuous scarcity of water. Plants subjected to continuous water starvation had markedly lower grain yield than those subjected to water-deficit conditions at post-anthesis stage. Application of kinetin before seed sowing or at the post-anthesis stage significantly reduced the negative effects of drought on flag leaf chlorophyll and stomatal conductance. Lower level of kinetin (75 mg/L) was found to be more effective in mitigating the inhibitory effects of water shortage on photosynthesis and growth, and improved grain yield under water scarcity.     

Development of ecoregion-based merchantable volume systems for Pinus brutia Ten. and Pinus nigra Arnold. in southern Turkey

Estimating individual tree volume is one of the essential building blocks in forest growth and yield models.Ecologically based taper equations provide accurate volume predictions and allow classification by merchantable sizes, assisting in sustainable forest management.In the present study, ecoregion-based compatible volume systems for brutian pine and black pine in the three ecoregions of southern Turkey were developed. Several well-known taper functions were evaluated. A secondorder continuous-time autoregressive error structure was used to correct the inherent autocorrelation in the hierarchical data, allowing the model to be applied to irregularly spaced and unbalanced data. The compatible segmented model of Fang et al.(For Sci 46:1–12, 2000) best described the experimental data. It is therefore recommended for estimating diameter at a specific height, height to a specific diameter, merchantable volume, and total volume for the three ecoregions and two species analyzed. The nonlinearextra sum of squares method indicated differences in ecoregion and tree-specific taper functions. A different taper function should therefore be used for each pine species and ecoregion in southern Turkey. Using ecoregionspecific taper equations allows making more robust estimations and, therefore, will enhance the accuracy of diameter at different heights and volume predictions.     

特色饮料“生命营养液”内源菌株CICC10822的鉴定及生物学特性

[目的]鉴定特色饮料"生命营养液"内源菌株CICC 10822并了解其生物学特性。[方法]采用传统微生物学分离培养方法对30℃条件下分离得到的新疆埃杜升"生命营养液"细菌CICC 10822进行多相分类鉴定。[结果]菌株CICC 10822接触酶反应阴性,硝酸盐还原阴性,淀粉水解阴性,精氨酸双水解酶阴性;能利用葡萄糖、果糖、核糖和半乳糖,不能利用麦芽糖、木糖、甘油、乳糖、甘露糖、山梨醇、纤维二糖、鼠李糖、阿拉伯糖,不液化明胶。利用基于形态学观察、生理生化特征分析及16S r DNA和phe S基因序列系统发育分析的微生物多相分类鉴定技术,将菌株CICC 10822鉴定为酸鱼乳杆菌(Lactobacillus acidipiscis)。[结论]试验结果为今后开展针对该菌的生物学功能研究奠定了基础。     

Influence of subacute and subchronic treatment of abcisic acid and gibberellic acid on serum marker enzymes and erythrocyte and tissue antioxidant defense systems and lipid peroxidation in rats

This study describes the subacute and subchronic effects of two plant growth regulators (PGRs) [abcisic acid (ABA) and gibberellic acid (GA₃)] on serum marker enzymes [aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine phosphokinase (CPK) and lactate dehydrogenase (LDH), γ-glutamil transpeptidase (GGT)], antioxidant defense systems [reduced glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT)] and lipid peroxidation level (Malondialdehyde = MDA) in various tissues of rats. Rats (Sprague-Dawley albino) were exposed to 75 ppm (parts per million) of ABA and GA₃. Seventy-five parts per million of PGRs as drinking water was administered orally ad libitum for 25 and 50 days continuously. The PGRs treatments caused different effect on the serum marker enzymes, antioxidant defense systems and the content of MDA in comparison to those of control rats. Results show that ABA caused a significant decrease in serum LDH and CPK activity with both periods. Also, GA₃ significantly decreased serum AST, CPK, and LDH activity with subacute and decreased serum ALT, CPK, LDH, and GGT treated with subchronic periods. The lipid peroxidation end product MDA significantly increased in the erythrocyte, liver, brain, and muscle of rats treated with both the period of GA₃ without significantly change in the erythrocyte and muscle of rats treated with the subacute period of ABA. The GSH levels were significantly depleted in the erythrocyte and brain of rats treated with both the period of GA₃ without any change in the erythrocyte, liver, brain, and muscle of rats treated with both the period of ABA. Also GSH levels in the muscle significantly depleted with the subchronic period of GA₃. Antioxidant enzyme activities such as SOD significantly decreased in the erythrocyte, liver and brain tissues but increased in the muscle tissue of rats treated with both the periods of GA₃. Meanwhile, SOD significantly decreased in liver and brain, and increased in muscle of rats treated with both the period of ABA. While CAT significantly decreased in the all tissues of rats treated with both the period of GA₃, decreased in the liver and muscle of rats treated with both the periods of ABA too. On the other hand, the ancillary enzyme GPx and GR activity in the erythrocytes, liver, brain and muscle were either significantly depleted or not changed with two periods of PGRs. The drug metabolizing enzyme GST activity significantly decreased in the brain of rats treated with subacute period of PGRs but increased in the erythrocytes of rats treated with subacute period of GA₃. As a conclusion, ABA and GA₃ had significantly increased the activity of hepatic damage enzymes. Also the rats resisted to oxidative stress via antioxidant mechanism. However, the antioxidant mechanism could not prevent the increases in lipid peroxidation in rat’s tissues. These data, along with changes, suggest that PGRs produced substantial systemic organ toxicity in the erythrocyte, liver, brain, and muscle during the period of a 25-day subacute and 50-day subchronic exposure.