Chlorophyll fluorescence for visualizing the spatial and temporal spread of Phytophthora alni subsp. alni in alder bark tissue

The impact of alder Phytophthora (Phytophthora alni subsp. alni) on corticular photosynthetic metabolism was explored via measurements of chlorophyll fluorescence. Stem inoculation induced a sharp reduction of maximum (F_v/F_m) and effective quantum yield of PSII (). Observations of the axial and radial spread of the pathogen revealed that near to the point of inoculation and in the whole centre of the stem lesion F_v/F_m and of the cortex chlorenchyma decreased to almost zero, indicating tissue necrosis. Low values of F_v/F_m and were also found in some presymptomatic regions beyond the visible stem lesion. In contrast, substantial photosynthetic activity was found in uninvaded parts of the inoculated trees and in the control. These stem parts showed a marked light‐adapted quantum efficiency of PSII as well as marked electron transport rates in their bark tissues. Thus, corticular photosynthesis stayed unaffected in these stem parts supporting stem carbon balance. Chlorophyll fluorescence measurements in the field illustrated that stem infection with P. alni subsp. alni and the effect on the bark tissues is not only highly heterogeneous but also underlies very quick temporal changes, due to a rapid destruction of the photosynthetic apparatus. The results show that chlorophyll fluorescence measurements and fluorescence imaging are useful indicators of tissue infection caused by Phytophthora infection of bark tissues. Chlorophyll fluorescence measurements can be used to map and visualize the spatial as well as temporal spread of bark pathogens and can give a first indication of invasion of the host tissue beyond the visible lesion.     

不同种源铁刀木在粤西的早期生长表现

收集云南普洱、台湾台北、云南西双版纳、广西凭祥、广西北海5个铁刀木（Cassia siamea）种源,比较分析了不同种源铁刀木的早期生长表现。结果表明,不同种源铁刀木早期生长差异显著(P<0.05),其中以广西凭祥种源生长综合表现最佳,2 a 生树高均值达2.73 m,地径均值达4.08 cm。5种种源保存率均较高,造林当年成活率达97%以上,且种源间差异不显著。     

当归四逆汤对糖尿病周围神经病变患者神经传导速度和踝肱指数的影响

目的 观察当归四逆汤对糖尿病周围神经病变患者神经传导速度和踝肱指数的影响。方法 将糖尿病周围神经病变患者随机分为对照组30例与治疗组30例,两组均口服甲钴胺作为基础治疗,治疗组加用当归四逆汤治疗,治疗4周后,观察并比较两组患者的总体疗效、周围神经传导速度及踝肱指数的改善情况。结果 治疗组总有效率90.0%显著高于对照组63.3%（P<0.05）,且其神经传导速度、踝肱指数改善优于对照组,差异有统计学意义（P<0.05）。结论 当归四逆汤治疗糖尿病周围神经病变有较好的疗效,能增强神经传导速度,改善踝肱指数值,可临床推广应用。     

修剪对苹果枝(梢)皮层总黄酮含量的影响

以“长富2号”、“玉华早富”苹果树为试材,采用NaNO₂-Al(NO₃)₃比色法测定总黄酮含量,研究了枝(梢)秋剪、冬剪后剪口自然暴露空气不同时长后枝(梢)皮层组织总黄酮含量的动态变化特征。结果表明,1)修剪处理后与未修剪情况下枝(梢)皮层组织总黄酮含量变化存在显著差异。2)秋季修剪后,果树秋梢皮层组织总黄酮含量在24 h内均呈波动变化,0～3 h逐渐升高,3～24 h逐渐下降; 修剪处理24 h后秋梢皮层组织总黄酮含量逐渐增加并趋于稳定,净增加率达50%以上。3)冬季修剪后,果树1年生枝条皮层组织总黄酮含量24 h以内的变化特征与秋季相同; 24 h后呈现波动变化,表现为24～48 h逐渐升高,48～168 h逐渐下降至初始值左右。修剪能够改变黄酮类化合物的代谢,影响枝(梢)总黄酮含量,可为指导苹果树修剪及枝条剪口的保护提供科学依据。     

适于FVS的长白落叶松树皮因子

为估算长白落叶松的去皮直径及树皮厚度等,利用小兴安岭南部68株长白落叶松解析木与生物量数据,对带皮胸径与去皮胸径之间、树干材积与木材材积之间、树皮厚度与相对树高之间、树皮因子与树高之间等相关模型进行了研究.结果表明,长白落叶松胸径处去皮直径的最优模型为D1B=0.922DOB(R2=0.99),胸径处树皮因子和树皮调整...     

尾巨桉树皮率及树皮纤维尺寸的变异研究

以广西贵港市平天山林场5年生、6年生和7年生的尾巨桉为对象,分析了不同树龄尾巨桉的树皮率和树皮纤维尺寸的株内变异特性。结果表明:尾巨桉的体积树皮率和重量树皮率均随着树干高度的增加而逐渐减小。树皮纤维长度随着树干高度的增加略有增加,但变化幅度不大;树皮纤维宽度、双壁厚度和壁腔比均随树干高度的增加而减小;树皮纤维长宽比则随树干高度的增加而增加。方差分析表明,不同树龄间尾巨桉树皮纤维长度和长宽比差异极显著,壁腔比差异不显著。     

Cassia occidentalis L.: A review on its ethnobotany,phytochemical and pharmacological profile

Cassia occidentalis L. is an annual or perennial Ayurvedic plant which is used in several traditional medicines to cure various diseases. This weed has been known to possess antibacterial, antifungal, antidiabetic, anti-inflammatory, anticancerous, antimutagenic and hepatoprotective activity. A wide range of chemical compounds including achrosin, aloe-emodin, emodin, anthraquinones, anthrones, apigenin, aurantiobtusin, campesterol, cassiollin, chryso-obtusin, chrysophanic acid, chrysarobin, chrysophanol, chrysoeriol etc. have been isolated from this plant. The presented review summarizes the information concerning the botany, ethnopharmacologyquery, phytochemistry, biological activity and toxicity of the C.occidentalis plant.     

肉桂主要病虫害及防治技术综述

文章对肉桂枝枯病、藻斑病、粉实病、炭疽病、根腐病、白粉病、褐斑病及煤污病的病原、症状、发生规律进行描述,对泡盾盲蝽、肉桂双瓣卷蛾、肉桂突细蛾、肉桂木蛾、肉桂瘿蚊、种子小蜂虫害的危害和生活习性进行总结,并提出防治对策,为肉桂病虫害治理提供参考。     

Effects of resistance of Eremocitrus glauca and Microcitrus australis to viroid infection: replication,accumulation and long‐distance movement of six citrus viroids

In studies to identify genotypes resistant to infection with citrus viroids, Eremocitrus glauca and Microcitrus australis were selected because their evolution in their habitat in Australia and New Guinea may have led to the selection of unusual traits. The movement and accumulation of Citrus exocortis viroid (CEVd), Hop stunt viroid, Citrus bent leaf viroid, Citrus dwarfing viroid, Citrus bark cracking viroid and Citrus viroid V (CVd‐V) in self‐rooted as well as in graft‐ propagated E. glauca and M. australis plants was assessed by northern hybridization, RT‐PCR and by topworking to the sensitive selection 861‐S1 of Etrog citron. In both plant species the inoculated viroids were undetectable unless these plants were grafted to a susceptible Citrus partner, the rough lemon rootstock and/or the topworked Etrog citron, which acted as viroid sources. The results obtained indicate that M. australis and in particular E. glauca are poor viroid hosts in which viroid replication/accumulation does not occur or is extremely inefficient. However, viroid downward and upward movement to grafted Citrus partners in which viroid replication and accumulation occurs efficiently was not impaired. Eremocitrus glauca and M. australis showed differences regarding their properties as viroid hosts, but for both species CEVd seemed to have the lowest affinity among the viroid species tested and CVd‐V the highest. Even though E. glauca and M. australis do not appear to be truly resistant to viroid infection, they are interesting genotypes for further characterization of the mechanisms involved in viroid infection.     

桑枝皮多糖的提取及组成成分与体外生物活性分析

为了更好地发掘桑枝皮的药用价值,采用热水浸提法从桑枝皮中分离提取多糖,其得率达到28.5%。采用薄层层析(TLC)法和非衍生化高效液相色谱(HPLC)法分析桑枝皮多糖的组成成分,初步推定桑枝皮多糖为一种杂多糖,由鼠李糖、木糖、阿拉伯糖、甘露糖、葡萄糖和半乳糖等单糖组成。桑枝皮多糖的体外生物活性试验显示其具有较强的对DPPH自由基的清除能力(IC50为1.7mg/mL)和对α-葡萄糖苷酶的抑制活性(IC50为0.298mg/mL)。上述结果提示桑枝皮多糖是降血糖和抗氧化的天然药物资源。