Seminal plasma proteins of Atlantic halibut (Hippoglossus hippoglossus L.)

Protein content and properties in the seminal plasma of Atlantic halibut (Hippoglossus hippoglossus) were assayed using spectrophotometric and electrophoretic methods. The protein concentration ranged from 6.4 ± 3.1 to 19.4 ± 3.4 mg ml⁻¹ and anti-proteolytic activity from 585.2 ± 104.6 to 2912.4 ± 367.4 U l^−l. A high correlation between anti-proteolytic activity and protein concentration (r = 0.95), and between sperm concentration and osmolality was found (r = 0.92). There was a significant decrease in anti-proteolytic activity from the first to the second sampling, but not in protein concentration. Anti-proteolytic activity and protein concentration were significantly affected by variations in individual males. Electrophoresis revealed four anti-proteolytic bands and individual differences in bands of proteolytic activity, which were subsequently characterized as metalloproteases and serine proteases.     

Cd2+、Hg2+、As3+对可口革囊星虫的急性毒性试验

采用次生体腔注射、静水法研究了Cd2 、Hg2 和As3 对可口革囊星虫的单一毒性试验。试验结果表明:Cd2 、Hg2 和As3 对星虫的24 h LD50分别为:158.79 mg/kg,87.39 mg/kg和295.80 mg/kg;48 h LD50分别为:74.94 mg/kg,39.89 mg/kg和46.35 mg/kg。Cd2 、Hg2 、As3 对星虫的毒性大小为:Hg2 >As3 ≈Cd2 ,LD50均随试验时间的延长而减小。毒性反应:注射Cd2 组星虫身体伸长,吻变细,肠管排出;注射Hg2 组身体变硬,分节;注射As3 组身体变软。相对增重方差分析显示:不同注射浓度,相对增重均有显著差异;不同处理时间,Hg2 、As3 处理的星虫有显著差异,而Cd2 处理的星虫无显著差异。     

喷锌对蕹菜锌含量及产量的影响

不同喷施浓度及喷施次数对蕹菜产量及茎叶锌含量的影响结果表明：喷施０．０５％及０．１％的硫酸锌液均能提高蕹菜的产量,但以０．０５％的处理对产量的提高作用最明显,浓度超过０．１％时,对蕹菜生长有抑制作用提高喷锌浓度,蕹菜锌含量的增加为叶片大于茎;喷施１～２次,有明显的增产效果,喷施超过２次反而减产;随着喷施次数的增加,蕹菜锌含量也增加。     

不同氮效率小麦品种临界氮浓度模型与营养诊断研究

为探讨不同氮效率小麦品种临界氮浓度模型的差异和开展小麦氮素营养诊断研究,基于两年大田试验,以不同氮效率小麦品种周麦27(高氮高效)、豫麦49-198(低氮高效)和矮抗58(低氮低效)为研究对象,系统分析了不同氮效率小麦品种地上部生物量、地上部氮含量和氮素营养指数的变化规律。结果表明,不同氮效率小麦品种地上部生物量和地上部氮含量均随施氮量的增加而增加,临界氮浓度(N_C)与地上部最大干物质(DM)均呈幂函数关系(N_C=aDM~(-b)),且氮高效型品种模型的两个参数(a和b)值均大于氮低效型品种。经检验,模型的标准化均方根误差分别为13.87%(周麦27)、7.7%(豫麦49-198)和13.02%(矮抗58),通过临界氮浓度模型所建立的氮素营养指数推荐的麦田施肥量均在120~225kg·hm~(-2)范围,其中周麦27和豫麦49-198的推荐施肥量分别为225和120kg·hm~(-2),矮抗58的推荐施肥量介于二者之间。     

Calibration and validation of optical chlorophyll‐measuring devices for use in predicting crude protein concentration in tropical grass herbage

The objective of this experiment was to evaluate the Fieldscout CM 1000 NDVI and Yara N‐Tester as easy‐to‐use and cost‐effective tools for predicting foliar chlorophylls (a, b and total) and crude protein (CP) concentrations in herbage from three tropical grass species. Optical chlorophyll measurements were taken at three stages (4, 8 and 12 weeks) of regrowth maturity in Guinea grass (Panicum maximum) and Mulato II (Brachiaria hybrid) and at 6 and 12 weeks maturity in Paspalum spp (Paspalum atratum). Grass samples were harvested subsequent to optical measurements for laboratory analysis to determine CP and solvent‐extractable chlorophylls (a, b and total) concentrations. Optical chlorophyll measurements and CP concentrations were highly correlated (Yara N‐Tester: r² = 0·77–0·89; Fieldscout CM 1000 NDVI: r² = 0·52–0·84). Crude protein prediction models from the Yara N‐Tester and Fieldscout CM 1000 NDVI accounted for 70–89% and 44–73% CP variability, respectively, in Mulato II and Guinea grass. The Yara N‐tester produced more accurate and reliable CP estimates based on very high concordance correlation coefficient [CCC (0·73–0·91)] and low rMSPE, mean and regression bias. It is concluded that the Yara N‐Tester produces more accurate and reliable CP estimates of tropical pastures.     

Inhibition study of red rice polyphenols on pancreatic α-amylase activity by kinetic analysis and molecular docking

This study sought to investigate the possible inhibition mechanism of red rice polyphenols (RRP) on pancreatic α-amylase (PA) activity. RRP showed strong inhibition against PA activity and the half-inhibitory concentration (IC₅₀) value was 3.61 μg/mL. The fluorescence quenching of PA by RRP was a combination of static quenching and dynamic quenching. RRP could aggregate with PA and the physiochemical properties of the aggregates were closely related to the concentration of RRP. Kinetic analysis suggested that the inhibition mode of RRP on PA was reversible inhibition, which was a mixing of competitive inhibition and noncompetitive inhibition. Molecular docking speculated that RRP could form hydrogen bonds with PA by binding to the catalytic active sites (ASP197, GLU233 and ASP300) and the microenvironments of TRP58 and TRP59 were altered, thus inhibiting PA activity.     

北极村樟子松与落叶松林区空气负离子浓度及其与气象因子的关系

为了揭示空气负氧离子浓度与林种及相关气象条件之间的关系,笔者于2013年夏、秋两季对北极村地区选取的具有代表性的样地进行负氧离子浓度的观测及研究,通过时间尺度平均值及相关性分析的方法,对采集数据进行统计分析,并得出北极村地区负氧离子浓度的总体水平以及其与林种和气象因子之间的变化关系。结果表明:漠河北极村空气负离子浓度的总体水平处于548~1203个/cm~3,平均值为892个/cm~3,负氧离子浓度大体上与空气温度呈正相关、与空气湿度呈负相关。落叶松样地整体负氧离子水平高于樟子松样地,不同季节对负氧离子浓度也有较大影响。揭示出北极村地区负氧离子浓度与林种、季节以及气象因子之间的变化关系。     

根际氧浓度对番茄幼苗生长发育的影响

为了探究设施园艺作物栽培时适宜的水气环境,采用水培试验,以河南四号和粉珍珠2个栽培番茄品种为研究对象,设置3个氧水平:低氧(0.5~2.0 mg/L)、正常氧(7.0~8.0 mg/L)和饱和氧(14.0~17.0 mg/L)处理,以不通气作为空白对照CK,研究根际不同氧浓度对番茄幼苗植株的形态生长、生物量、根系活力和光合色素的影响。结果表明,随着根际氧浓度的增加,番茄幼苗的长势越好,根系活力增加,但叶绿素含量降低。在处理末期,正常氧处理与饱和氧处理显著提高番茄幼苗的最长根长并增加番茄幼苗的干、鲜质量。其中,在18 d河南四号正常氧和饱和氧处理下总干质量比CK分别增加24.00%和74.86%,而低氧处理比CK降低3.43%;最长根长分别增加67.23%和230.55%,而低氧处理比CK降低1.63%。饱和氧处理下根系更发达健壮,地上部分长势更好,生物量积累最多。因此,在设施园艺栽培管理中,增加营养液中根际氧浓度有利于番茄生物量的积累,进而提高产量。     

乌兰布和沙漠东北缘防护林内外沙尘暴低空结构特征

基于内蒙古磴口荒漠生态系统国家定位观测研究站近地层(050m)风沙监测塔所收集的8次沙尘暴的沙尘水平通量、垂直通量和风速风向数据,对乌兰布和沙漠东北缘中小尺度条件下的防护林内外沙尘暴过程中风况变化、沙尘分布特征以及防护林对沙尘暴的影响进行研究。结果表明:①沙尘暴发生过程中,防护林内外风速均随高度增加呈现递增趋势,风速廓线特征遵循幂函数,防护林内外均以W、WNW、NE方向为主,但每个方向所占比例不同。②防护林外沙尘水平通量及沙尘浓度随高度增高显著减小,其垂直分布特征均符合指数函数关系;防护林内沙尘水平通量及沙尘浓度则随着高度增高缓慢上升,其垂直分布特征均符合幂函数关系。沙尘垂直通量则均随着高度的增高明显减小,其垂直分布特征均符合幂函数关系。③沙尘暴经过防护林体系时,风速显著削弱,平均消减31.03%;沙尘水平通量降低298.16g·m^-2,垂直通量降低0.37g·m^-2,沙尘浓度降低22.48g·m^-2。     

Low soil temperature reducing the yield of drip irrigated rice in arid area by influencing anther development and pollination

Drip irrigation can produce high rice yields with significant water savings; therefore, it is widely used in arid area water-scarce northern China. However, high-frequency irrigation of drip irrigation with low temperature well water leads to low root zone temperature and significantly reduce the rice yield compared to normal temperature water irrigated rice, for example, reservoir water. The main purpose of this paper is to investigate the effects of low soil temperature on the yield reduction of drip irrigated rice in the spike differentiation stage. The experiment set the soil temperatures at 18°C, 24°C and 30°C under two irrigation methods(flood and drip irrigation), respectively. The results showed that, at the 30°C soil temperature, drip irrigation increased total root length by 53% but reduced root water conductivity by 9% compared with flood irrigation. Drip irrigation also increased leaf abscisic acid and proline concentrations by 13% and 5%, respectively. These results indicated that drip irrigated rice was under mild water stress. In the 18°C soil temperature, drip irrigation reduced hydraulic conductivity by 58%, leaf water potential by 40% and leaf net photosynthesis by 25% compared with flood irrigation. The starch concentration in male gametes was also 30% less in the drip irrigation treatment than in the flood irrigation treatment at soil temperature 18°C. Therefore, the main reason for the yield reduction of drip irrigated rice was that the low temperature aggravates the physiological drought of rice and leads to the decrease of starch content in male gametes and low pollination fertilization rate. Low temperature aggravates physiological water deficit in drip irrigated rice and leads to lower starch content in male gametes and low pollination fertilization rate, which is the main reason for the reduced yield of drip irrigated rice. Overall, the results indicated that the low soil temperatures aggravated the water stress that rice was under in the drip irrigated environment, causing declines both in the starch content of male gametes and in pollination rate. Low temperature will ultimately affect the rice yield under drip irrigation.