Effect of xylem fluid from susceptible and resistant grapevines on developmental biology of Xylella fastidiosa

Xylella fastidiosa causes Pierce??s disease (PD), a serious disease in grapevines, and grapevine cultivars vary in susceptibility to X. fastidiosa in the field. The mechanism(s) by which this occurs has not been clearly elucidated. To explore possible mechanisms, X. fastidiosa cells from a PD strain were grown in pure xylem fluid of PD-susceptible grapevines, Vitis vinifera and V. labrusca, versus PD-resistant grapevines, V. champinii and V. smalliana. When grown in xylem fluid from the susceptible species, X. fastidiosa cells formed a heavier biofilm compared to those in xylem fluid from the resistant species. Differential expression of selected genes of X. fastidiosa cultured in the xylem fluids of V. vinifera and V. smalliana was analyzed using a DNA macroarray. Compared with xylem fluid of V. smalliana, xylem fluid of V. vinifera stimulated the expression of X. fastidiosa genes involved in virulence regulation, such as rpfC, gacA, xrvA, gcvR, and cysB, and genes involved in biogenesis of pili and twitching motility, such as pilI, pilU, pilE and pilG. Increased expression of virulence genes likely contributes to the expression of PD symptom in the susceptible grapevines, whereas reduced expression of these genes may lead to limitation of symptoms in resistant grapevines.     

Physiological and Biochemical Changes of IrlVHA-c gene Transgenic Tobacco Seedlings and Self-crossed Progeny Under NaHCO3 Stress

In order to study the alkali resistivity of VHA-c in Iris lacteal. (IrlVHA-c), the transgenic tobacco seedlings harboring IrlVHA-c gene from Iris lactea (T0), the self-crossed progeny (T1), and the non-transgenic lines of tobacco seedlings were grown in Hoagland nutrient solutions supplemented with 0, 100, 200, 300, 400 mmol·L-1 NaHCO3 . The MDA content, CAT, POD and SOD activity, electrical conductivity, chlorophyll content, soluble sugar content, proline content and polyphenol oxidase activity of the seedlings were determined. The results showed that the transgenic lines of tobacco maintained a high activity up to 200 mmol·L-1 NaHCO3 , and activity was slightly lower at 300 mmol·L-1 NaHCO3 . When the concentration of NaHCO3 was as high as 400 mmol·L-1 the seedlings were badly hurt. In addition, the activity of T0 and T1 transgentic tobacoo was maintained more or less. While the non-transgenic lines of tobacco could maintain viably up to 100 mmol·L-1 NaHCO3 , and they could not survive at 400 mmol·L-1 NaHCO3 . The conclusion was drawn that the alkali resistance of the tobacoo transformed IrlVHA-c was noticeably improved.     

中国传统园林中石—生组合景观探析

山石与植物是中国传统园林中必不可少的造园要素,山石为园林的骨架,而植物是其毛发.研究分析中国传统园林中石-生组合景观的相关理论,阐述了山石类型及其植物配置和景观特点,系统地分析了石-生组合景观的常见形式,希望对现代园林景观的建造有一定的指导作用.     

Spring growth of almond nursery trees depends upon nitrogen from both plant reserves and spring fertilizer application

Summary

June-budded ‘Nonpareil’/‘Nemaguard’ almond (Prunus dulcis (Mill) D. A. Webb) trees were fertigated with one of five nitrogen (N) concentrations (0, 5, 10, 15, or 20 mM) from July to September. The trees were sprayed with either water or 3% urea in October, then harvested bareroot after natural leaf fall, and stored at 2°C. One set of trees was destructively sampled for total N content; the remaining trees were transplanted into N-free media in the spring after cold storage. After budbreak, these trees were supplied for 70.d with either N-free Hoagland’s solution or Hoagland’s solution containing ¹⁵N-NH₄NO₃. Nitrogen concentrations in both stem and root tissues were positively correlated with the N-fertigation concentration. Fall foliar urea applications increased levels of stem and root N regardless of the N-fertigation concentration. During the first 70 d of spring growth, the trees utilized nitrogen from both their reserves and spring fertilizer applications. The amount of N reserves used for growth of new shoots and leaves was proportional to the total amount of reserves. Trees with low N reserves relied primarily on the spring fertilizer as their source of nitrogen. We conclude, therefore, that both reserve N and spring-applied N fertilizers are important for enhancing the regrowth of bareroot almond nursery trees during establishment after transplanting. Nitrogen fertilization in the spring can especially improve the performance of trees with low N reserves.     

An approach to the evaluation and management of natural carbon sinks: From plant species to urban green systems

The maintenance and improvement of current natural carbon sinks, as well as the creation of others, are presently considered among the main strategies by which to address global climate change, and are pursued in parallel to the implementation of policies of carbon emission reduction. To date, this approach has been applied mainly to forest areas, obtaining relevant results that help to identify areas of weakness in the strategy and to design appropriate management measures. Nevertheless, under the current situation, and at territorial level, urban areas and infrastructures, in which urban green systems play a significant role, present opportunities for contributing towards carbon sink potential. Various studies conducted by our research group have emphasized the role of urban green systems as natural carbon sinks, including research conducted under initiatives from European authorities (“Climeport project/Mediterranean Ports’ Contribution to Climate Change”), regional government (Andalusian Strategy against Global Climate Change) and Andalusian universities (Andalusian University Rectors Climate Change Pact). Through these projects, we have assessed entire systems, identifying the species of urban trees and shrubs with the greatest sink potential under different climate scenarios, proposing garden management schemes, and providing a basis for the creation, design, management and improvement of natural carbon sinks in the cities.     

Influence of delphinidin-3-glucoside on oxidized low-density lipoprotein-induced oxidative stress and apoptosis in cultured endothelial cells

Increased oxidative stress and apoptosis were detected in atherosclerotic lesions. Oxidized low-density lipoprotein (oLDL) may induce oxidative stress and apoptosis via multiple pathways in vascular endothelial cells (EC). Delphinidin-3-glucoside (D3G), an anthocyanidin glycan enriched in dark-skin berries, may neutralize those effects of oLDL in EC. The present study demonstrated that oLDL increased the generation of intracellular NADPH-dependent superoxide and impaired redox status in cultured porcine aortic EC (PAEC). The activities of mitochondrial respiratory chain complex I-IV and the contents of NADH dehydrogenase (ND)1, ND6 (complex I enzyme subunits), or cytochrome b (complex III enzyme subunit) were significantly reduced in PAEC treated with oLDL compared to controls. Treatment with oLDL significantly increased the abundances of NADPH oxidase (NOX)2, NOX4, and p22phox in PAEC. oLDL reduced cell viability and the protein content of B-cell lymphoma (Bcl)-2, but increased the content of caspase 3 in PAEC. Co-treatment with D3G prevented oLDL-induced increases in intracellular superoxide or in the protein content of NOX2, NOX4, p22phox, or caspase 3, inhibited the impairment of redox statues or cell viability, and prevented the attenuation of mitochondrial enzyme activities and the reductions of Bcl-2, ND1, or cytochrome b contents in PAEC. The findings suggest that oLDL induced oxidative stress and apoptosis in EC, which was associated with the activation of NOX, the impairment of mitochondrial respiration chain enzymes, and the disorder of key regulators for apoptosis. D3G neutralized the harmful effects of oLDL on oxidative stress, mitochondrial dysfunction, and apoptosis in cultured vascular EC.     

Modelling temperature,moisture and surface heat balance in bare soil under seasonal frost conditions in China

Soil heat and moisture processes are interconnected, especially during low temperatures. To examine the interaction between soil temperature and moisture under freeze‐thaw cycles, a physical process‐based model (CoupModel) coupled with uncertainty analysis was applied to 3‐year measurements under seasonal frost conditions from a site in the black soil belt of northeast China. The uncertainty in parameters and measurements was described by general likelihood uncertainty estimation (GLUE). To identify the degree of linkage between soil temperature and moisture, three criteria were applied to them separately or together. The most sensitive parameters among 26 site‐specific parameters were closely related to soil heat, soil evaporation and freeze‐thaw processes. Soil temperature was simulated with less uncertainty than soil moisture. Soil temperature measurements had the potential to improve model performance for soil water content, whereas soil moisture measurements demonstrated a trade‐off effect when finding a model with good performance for both temperature and moisture. During winter conditions the uncertainty ranges of soil temperature were most pronounced, probably because of the greater complexity of soil properties during the freeze‐thaw process and the uncertainty caused by snow properties. The largest uncertainty ranges of both soil water content and soil water storage were found mainly in the deep soil layers. The simulated surface heat fluxes are an important output of the model and it is of great value to compare them with the results from regional climate models and micrometeorological measurements.     

从气候影响分析谈大豆生产对策

分析了今年前期异常的气候对大豆生育的影响,提出了以抢积温促早熟为中心的生产对策,包括树立抢积温促早熟的思想,抓紧进行垅沟深松,勤铲勤趟的田间管理,追肥和叶面喷肥等促进生长、调节生育的措施和及时防治病虫害等技术对策。     

The use of k-means and artificial neural network to classify cotton lint

The use of High Volume Instrument (HVI) to measure cotton lint characteristics produces high dimensional data. A model which utilized Kohonen Self Organizing Maps (SOM) to visualize cotton lint HVI data, k-means clustering technique to cluster the data and Probabilistic Neural Network (PNN) for data classification was designed and tested using Kenyan cotton lint. According to the model the Kenyan cotton lint can be grouped into four clusters, which were successfully classified by using PNN with a correlation coefficient (R-value) of 1.