The Physiology and Biochemical Tolerance of Cabbage to Se (VI) Addition to the Soil and by Foliar Spraying

The effects of selenium (Se) (VI) soil fertilization with 2 μg Se L^?1 or foliar spraying twice with 20 mg Se L^?1 in the form of sodium (Na) selenate on the physiological and biochemical characteristics of cabbage plants were studied. The ability of the plants to take up Se and translocate it to different parts of the plants was also studied. Despite the high concentration of Se in the foliar solution, there was no effect on photosynthesis, transpiration rate, photochemical efficiency of PSII, or electron transport system activity. The amount of chlorophyll and anthocyanins were unchanged. At harvest, the concentration of Se in control plants was lower than 100 ng Se g^?1 dry weight (DW), while plants treated with 20 mg Se L^?1 contained 5500 ng Se g^?1. Selenium enriched cabbage could be used in human nutrition. The tolerance of cabbage to Se could be explained by the formation of insoluble compounds that are not available for the plant.     

Five-year trends in soil arthropod densities in pine forests with various levels of vitality

Summary A comparative field study was conducted to study the correlation between forest vitality and the abundance of soil microarthropods. During 5 years the vitality of six pine forests within the Veluwe area, the Netherlands, was estimated by the number of needle year-classes, while soils were sampled and extracted for various soil microarthropod groups. Within sites the number of needle year-classes in the forest stands fluctuated over the 5 years, while the collembolan family Sminthuridae showed a trend towards a decreasing population density and the density of the cryptostigmatid mite Platynothrus peltifer Koch increased. Among sites there was a significant positive correlation between the number of needle year-classes and the relative abundance of P. peltifer. The results imply that soil microarthropods may indicate changes in physical and chemical factors in relation to soil fertility and vitality of the trees.     

华西雨屏区常绿阔叶林凋落叶分解过程中木质素降解对模拟氮、硫沉降的响应

目的 探索亚热带常绿阔叶凋落叶分解过程中木质素降解对氮、硫沉降的响应。 方法 采用氮、硫双因素3水平试验设计方法,设置对照（CK）、低氮（LN,50 kg·hm-2·a-1）、高氮（HN,150 kg·hm-2·a-1）、低硫（LS,200 kg·hm-2·a-1）、高硫（HS,400 kg·hm-2·a-1）、低氮低硫（LNLS）、高氮低硫（HNLS）、低氮高硫（LNHS）和高氮高硫（HNHS）9个处理,分析氮、硫沉降对华西雨屏区常绿阔叶林凋落叶分解过程中木质素降解的影响。 结果 模拟氮、硫沉降1年时间,LN、LNLS和HNLS对木质素残留率、多酚氧化酶和过氧化氢酶活性的影响不显著;LS显著降低了木质素残留率,显著增加了凋落叶C/N、纤维素损失率、多酚氧化酶和过氧化物酶活性;HN、HS、LNHS和HNHS显著增加了木质素残留率,显著降低了凋落叶C/N、纤维素损失率、多酚氧化酶和过氧化物酶活性;氮沉降和硫沉降对木质素降解的交互作用显著。 结论 不同氮、硫沉降水平对华西雨屏区常绿阔叶林凋落叶分解过程中木质素降解及相关酶的影响不同,在氮、硫沉降量持续增加的背景下,氮、硫沉降相互作用,共同影响凋落叶分解过程中木质素的降解,进而影响凋落叶分解过程。     

维生素K3对松浦镜鲤幼鱼血清生化指标的影响

为研究饵料中维生素K3添加水平对松浦镜鲤(Cyprinus carpio Songpu carp)血清生化指标的影响,寻找维生素K3产生毒性的敏感指标,为饲料中维生素K3的添加限量提供数据.在水温24℃,溶氧7.46～8.61mg/L条件下,在以豆粕和鱼粉为蛋白源的基础饲料中(维生素K1含量0.54mg/kg,维生素K2未检出)添加不同水平的维生素K3(甲萘醌烟酰胺亚硫酸盐,甲萘醌≥49.9％),得到甲萘醌实际浓度为0,2.92,4.86,9.71,19.48,38.66,980.00 mg/kg 7组试验饲料,饲喂初始体质量为(2.58±0.16)g的松浦镜鲤,饲养试验时间为60d.结果表明:饲料中维生素K3添加水平对松浦镜鲤血清中的总蛋白(TP)、白蛋白(ALB)、球蛋白(GLB)、总胆红素(TBIL)、直接胆红素(DBIL)、间接胆红素(IBIL)、补体C3、C4的含量以及谷-草转氨酶的活性均无显著影响(P＞0.05).在最高剂量组(980 mg/kg)中,血清中谷-丙转氨酶的活性显著大于2.92 mg/kg试验组,肌酐含量显著大于9.71 mg/kg试验组(P＜0.05);尿素氮在高剂量组(≥38.66 mg/kg)的含量是其他试验组的2～3倍.可见,60d投喂不添加维生素K3的日粮不会对松浦镜鲤幼鱼血清生化指标产生不利影响,肾脏对维生素K3的反应早于肝脏,当维生素K3添加量≥38.66 mg/kg时,会影响松浦镜鲤的肾脏功能.     

维生素浸种和电场处理对菜豆生长发育初期的影响

维生素是生物代谢所必需的有机化合物,它对调节植物的生长具有重要作用.本试验利用不同种类及浓度维生素对菜豆种子进行浸种处理,然后沙培试验.待播种2～10 d后,分别测定种子的萌发率、菜豆幼苗的生长发育情况,并结合根系活力测定分析,探讨6个种类、4个浓度的维生素对菜豆种子萌发、幼苗生长初期的影响.同时,实验设置了外加电场(200 V/cm,60 min)处理菜豆种子,试图探究电场对菜豆种子萌发及生长的影响.结果表明:维生素对菜豆种子的萌发和生长具有显著的影响,但是作用效应与其种类和浓度均相关.电场处理在促进种子根系生长,提高幼苗初期根冠比等有显著影响,特别是在提高根系活力方面,远大于维生素对菜豆种子的促进作用;然而在株高和叶宽等形态发育上效应不显著.     

补肾化瘀方对PCOS大鼠子宫内膜整合素αvβ3及LIF表达的影响

目的 观察补肾化瘀方对多囊卵巢综合征（PCOS）大鼠子宫内膜整合素αvβ3及白血病抑制因子（LIF）的影响。方法 100只SD大鼠随机分为25只为空白对照组,75只为模型制备组,予颈背部皮下注射脱氢表雄酮（dehydroepiandrostexone,DHEA）溶液建立PCOS大鼠模型,判定造模成功后随机分为模型对照组、达英-35组、补肾化瘀方组,分别用蒸馏水、达英-35及补肾化瘀方对大鼠灌胃给药,连续灌胃21 d,停药7 d为1周期,3个周期后停药,按雌雄鼠1：1合笼,并于妊娠第4天处死大鼠,采用免疫组化法检测PCOS大鼠子宫内膜整合素αvβ3及LIF的表达。结果 （1）与空白对照组比较,模型对照组、达英-35组、补肾化瘀方组整合素αvβ3表达均较低（P<0.05）;与模型对照组比较,补肾化瘀方组整合素αvβ3较高（P<0.05）,达英-35组整合素αvβ3较低（P>0.05）。（2）与空白对照组比较,模型对照组和达英-35组LIF较低（P<0.05）;与模型对照组比较,补肾化瘀方组LIF较高（P<0.05）。结论 补肾化瘀方可提高PCOS大鼠子宫内膜整合素αvβ3及LIF的表达,这可能是其改善子宫内膜容受性的机制之一。     

植物富硒栽培研究进展综述

从硒在自然界中的存在形态、硒与人体健康、硒对植物生长影响、硒对植物次生代谢的影响以及植物富硒栽培的常规技术等方面对植物富硒栽培的研究进行了论述,提出了在植物富硒栽培方面存在的问题,并展望了富硒栽培应用的发展趋势。     

Selenium distribution and nitrate metabolism in hydroponic lettuce(Lactuca sativa L.): Effects of selenium forms and light spectra

A deficiency in selenium(Se) in the human diet is a worldwide problem. The intake of Se-rich vegetables can be a safe way to combat Se deficiency for humans. However, most leafy vegetables can accumulate a high content of nitrates, which poses a potential threat to human health. Light is an important environmental factor that regulates the uptake and distribution of mineral elements and nitrogen metabolism in plants. However, the effects of Se forms and light conditions, especially light spectra, on the uptake and translocation of Se and on nitrate reduction are poorly understood. In this study, lettuce(Lactuca sativa L.) was treated with exogenous Se applied as selenate(10 mmol L~(-1)) and selenite(0.5 mmol L~(-1)) and grown under five different light spectra: fluorescent light(FL), monochromatic red LED light(R), monochromatic blue LED light(B), and mixed red and blue LED light with a red to blue light ratio at 4(R/B=4), 8(R/B=8), and 12(R/B=12), respectively. The effects of light spectra and Se forms on plant growth, photosynthetic performance, Se accumulation and nitrate reduction were investigated. The results showed that the light spectra and Se forms had significant interactions for plant growth, foliar Se accumulation and nitrate reduction. The Se concentration and nitrate content in the leaves were negatively correlated with the percentage of red light from the light sources. Compared to Se applied as selenite, exogenous Se applied as selenate was more effective in reducing nitrate via promoting nitrate reductase and glutamate synthase activities. The lowest nitrate content and highest plant biomass were observed under R/B=8 for both the selenate and selenite treatments. The significant effect of the light spectra on the root concentration factor and translocation factor of Se resulted in marked variations in the Se concentrations in the roots and leaves. Compared with FL, red and blue LED light led to significant decreases in the foliar Se concentration. The results from this study suggest that the light spectra can contribute to Se distribution and accumulation to produce vegetables with better food quality.     

富硒海参饲料加工与使用方法对硒元素溶失率的影响

为解决富硒海参饲料的硒元素溶解损失问题,选择糊化淀粉浓度、后熟化温度、浸泡时间、浸泡温度4个因素作为研究对象,采用4因素3水平正交试验,对在糊化淀粉浓度分别为0、4%、8%,后熟化温度分别为60、120、180℃,浸泡时间分别为4、8、12h,浸泡温度分别为5、15、25℃条件下,富硒海参饲料中硒元素的溶解损失情况进行了试验。结果表明:4个因素对富硒海参饲料浸泡后硒元素溶失率的影响顺序为浸泡时间糊化淀粉浓度浸泡水温后熟化温度;富硒海参饲料的最佳加工方法为,将海参幼参饲料粉末与糊化淀粉浓度为8%的淀粉糊搅拌均匀,挤压成颗粒,在后熟化温度60℃下烘干;富硒海参饲料的最佳使用方式为,在水温25℃下,幼参摄食高峰前4h内投喂。     

南方鲇泌尿系统的结构

南方鲇肾前部分离,中后部相连,有两条肾索,属于硬骨鱼类的Ⅱ-B型肾,有2-9个斯坦尼斯小体.肾单位弥散分布于肾组织中,肾小体单个分布,肾前中后三部分别为3.8,3.4,2.6个/mm^2,平均直径66.5μm.肾小球毛细血管为有孔型,其间有系膜细胞.足细胞的足突与肾小球毛细血管紧贴并形成滤过孔.肾小管分化为颈段、第一近端小管（PⅠ）、第二近端小管（PⅡ）、远端小管（DS）、集合小管（CS）.颈段（NS）为立方上皮;PⅠ、PⅡ细胞柱状,有丰富的纹状缘.PⅠ细胞顶部有明显PAS阳性带,含有粗面内质网、线粒体及大量电子致密物质.与PⅠ、PⅡ伴行的毛细血管均为有孔型.DS、CS为立方上皮,线粒体、质膜内褶丰富.肾单位除颈段外的各段上皮均有大量游走细胞.各级收集管汇成中肾管通入膀胱.