INTERACTION BETWEEN WATER ALKALINITY AND NUTRIENT SOLUTION PH ON THE VEGETATIVE GROWTH,CHLOROPHYLL FLUORESCENCE AND LEAF MAGNESIUM,IRON, MANGANESE,AND ZINC CONCENTRATIONS IN LETTUCE

Alkalinity of water is considered critical for plant growth. Interactions between water alkalinity and solution pH on lettuce were investigated. Seeds of romaine type lettuce were sown in pots containing perlite and irrigated with a high alkaline nutrient solution at four pH values (5, 6, 7, and 8). Considering the high amount of Fv/Fm at pH 5; higher shoot growth (at pH 5) could be due to the improvement of the efficiency of the photosynthesis apparatus of plants and consequently higher photochemical quantum yield. Although, magnesium (Mg) concentration in leaves increased with elevating pH up to 7 and then decreased at 8, but iron (Fe), manganese (Mn), and zinc (Zn) concentrations decreased at higher solution pH levels, constantly. In commercial lettuce production in which water with high pH and carbonate species is normally used, it is better to use safe acids to reduce the pH in nutrient solutions to 5.     

干旱区城市化对城市内河水质的影响研究——以吐曼河为例

随着城市社会经济的迅速发展，工业主导的城市化过程带来了许多城市生态环境问题，引起了城市内河水质的恶化。采用1996～2000年喀什市吐曼河水质观测数据、1990年与1999年卫星遥感图像和城市发展中有关的社会经济统计数据与土地利用资料，在3S技术的支持下，运用地表水污染综合指数法，对吐曼河水质进行评价，定量与定性相结合分析了干旱区城市化对城市内河水质的影响。结果表明：大气中的总悬浮颗粒是导致吐曼河水质严重污染的主要原因。此外，城市化所带来得人口增加、工业化与土地利用方式的改变也一定程度的影响了吐曼河的水质。     

IL-4, IL-5 and IFN-gamma mRNA expression in pulmonary lymphocytes in equine heaves

Heaves is a common condition of horses of cold climate that is characterized by small airway inflammation and obstruction following exposure of susceptible horses to moldy hay and straw. It has been shown that helper T lymphocytes (Th) orchestrate the inflammatory response in asthma and in various animal models of allergic lung diseases by the release of Th2-type cytokines. Results of previous studies indicate that a predominant expression of Th2-type response by airway cells may also be present in heaves. To evaluate the temporal mRNA expression of Th1 (IFN-gamma) and Th2 (IL-4, IL-5) type cytokines in heaves and their relationship to clinical disease, we studied the pulmonary mechanics and cytokine mRNA expression (IL-4, IL-5 and IFN-gamma) in bronchoalveolar lavage lymphocytes of horses with heaves (n=6) and control (n=6) before and after 24h and 9 days of continuous natural inhalation challenge. Starting 24h after challenge horses with heaves, but not control horses, had a significant increase in pulmonary elastance and the number of lymphocytes expressing mRNA for IL-4 and IL-5. These changes were further increased at 9 days, at which time the number of cells positive for IFN-gamma mRNA was decreased. In this study we have shown that BAL lymphocytes of horses with heaves during clinical exacerbation have a predominant Th2-type cytokine response and that this response coincides in time with the presence of airway obstruction.     

Nocardia farcinica--a significant cause of mastitis in goats in Sudan

Fifteen of 100 mastitic milk samples from goats suffering from mastitis were tentatively identified as members of the genus Nocardia on the basis of selected phenotypic and chemotaxonomic characteristics. Six of the 155 strains were confirmed as Nocardia farcinica by 16S rDNA gene sequencing and subsequent aligning with relevant actinomycetes found in electronic databases and 2 by other identification criteria. N. farcinica is a serious cause of mastitis with a significant prevalence (15%) among the examined goats. Efforts are needed to optimise and simplify isolation and identification methods.     

Phytotoxicity of solanapyrones A and B produced by the chickpea pathogen Ascochyta rabiei(Pass.) Labr. and the apparent metabolism of solanapyrone A by chickpea tissues

When chickpea shoots were placed in solanapyrone A, the compound could not be recovered from the plant and symptoms developed. These consisted of loss of turgor, shrivelling and breakage of stems and flame-shaped, chlorotic zones in leaflets. In similar experiments with solanapyrone B, only 9.4% (22 μ g) of the compound taken up was recovered and stems remained turgid but their leaflets became twisted and chlorotic and some abscized.Cells isolated from leaflets of 12 chickpea cultivars differed by up to five-fold in their sensitivity to solanapyrone A and this compound was 2.6–12.6 times more toxic than solanapyrone B, depending on cultivar.Glutathione reacted with solanapyrone A in vitro reducing its toxicity in a cell assay and forming a conjugate. Measurement of reduced glutathione concentration and glutathione-S-transferase (GST) activity among cultivars showed that the differences of their means were highly significant and both were negatively and significantly correlated with their sensitivity to solanapyrone A. Treatment of shoots with solanapyrone A enhanced total, reduced and oxidized glutathione content as well as GST activity 1.26-, 1.23-, 1.50- and 1.94-fold, respectively. Similarly, treatment of shoots with the safener, dichlormid, also raised total, oxidized and reduced glutathione levels and GST activity 1.42-, 1.07-, 1.43-, 1.42-fold, respectively. Cells isolated from shoots treated with dichlormid at 150 and 300 μ g per shoot were 2.45 and 2.66 times less sensitive to solanapyrone A, with LD₅₀values of 71.5 and 77.8 μ g ml⁻¹, respectively, as compared to 29.2 μ g ml⁻¹for controls.     

Evidence for age- and size-mediated controls of tree growth from grafting studies

Vegetative propagation techniques such as grafting can be used, in conjunction with field studies, to decouple the relative effects of age and size on tree metabolism and growth. Despite interest in this approach, little attention has been paid to the best metrics for assessing the growth performance of grafted plants over time. Based on an analysis of the grafting literature and our own data, we show that the choice of metrics to assess tree growth can entirely change the conclusions reached about the relative importance of age versus size. We recommend that absolute as well as relative rates of growth are calculated and that scion size be standardized as much as possible at the start of the experiment. Once proper metrics are chosen, all of the available published evidence is largely concordant with two concepts: (1) age-mediated controls of tree growth are likely to be important during the first few years of a tree's life (before phase change); and (2) after the first few years of a tree's life, size-mediated factors largely prevail over age-mediated factors in determining tree growth rates. We found no support for theories invoking age-mediated sink limitations in old trees.     

Erratum to: Wild pistachio tree (Pistacia mutica) in the Qalajeh forest region of western Iran

<正>Erratum to:Journal of Forestry Reasearch,(2013)24(3):611-614DOI10.1007/s11676-013-0393-2The original version of this article unfortunately contained one mistake in author name in the footnote.The second author's name,"Mousa Rasouli",actually should be Hamid Soofi Mariv.The corrected version of the footnote should be as the following:     

Measuring crop status using multivariate analysis of hyperspectral field reflectance with application to disease severity and plant density

Using spectral reflectance to estimate crop status is a method suitable for developing sensors for site-specific agricultural applications. When developing spectral analysis methods, it is important to know the influence of different crop parameters on the spectral reflectance profile. The objective of this report was to present and evaluate a multivariate method for objective hyperspectral analysis in the examination of how different parts of the reflectance spectrum are affected by disease severity and above ground plant density. Data from two field experiments were used; fungal disease severity assessments in wheat 1998 and above ground plant density measurements 2003. The analysis method consisted of two steps: a pre-processing step where the data was normalized and a classification step for estimating the crop variable. Using only 12% of the data as training data, the method resulted in coefficients of determination (R ²) of 94.3% for the disease severity data and 96.9% for the plant density data. The hyperspectral analysis method presented could also be used to extract spectral signatures of disease severity and plant density using the experimental data. In general, two types of spectral signatures for both data sets, with respect to increasing disease severity and decreasing plant density, were observed (1) a flattening of the green reflectance peak together with a general decrease in reflectance in the near infrared region and, (2) a decrease of the shoulder of the near infrared reflectance plateau together with a general increase in the visible region between 550 and 750 nm.     

A genomic regulatory network for development

Development of the body plan is controlled by large networks of regulatory genes. A gene regulatory network that controls the specification of endoderm and mesoderm in the sea urchin embryo is summarized here. The network was derived from large-scale perturbation analyses, in combination with computational methodologies, genomic data, cis-regulatory analysis, and molecular embryology. The network contains over 40 genes at present, and each node can be directly verified at the DNA sequence level by cis-regulatory analysis. Its architecture reveals specific and general aspects of development, such as how given cells generate their ordained fates in the embryo and why the process moves inexorably forward in developmental time.     

Comparison of different soilless media for growing gerbera under alkalinity stress condition

A factorial experiment was developed with two factors of the growing medium (v/v): 100% coconut fiber (CF), 75% vermicompost+25% perlite (VP), 25% zeolite+75% perlite (ZP), 75% peat+25% perlite (PP), 75% coco chip+25% perlite (CCP), 75% coconut fiber+25% perlite (CFP) and 100% perlite (P); and sodium bicarbonate (NaHCO₃) (0, 20 and 40 mM) involving the growth of gerbera cv. Dafne. Compared with CF substrate, NaHCO₃ in the nutrient solution caused significant decrease in vegetative and reproductive traits and nutrient concentration [especially iron, phosphorus, and magnesium (Fe, P and Mg)] in the rest of the media. The improved crop performance of plants grown onto CF substrate was attributed to their strong capacity to accumulate Fe in the aerial part under alkaline conditions and to maintain a better plant nutritional status (higher P and Mg). It is concluded that the use of CF substrate could provide a useful tool to improve alkalinity tolerance of gerbera plants under NaHCO₃ stress.