60Co-γ辐射对大花紫薇叶绿素荧光特性的影响

为探究60Co-γ射线辐射处理种子对大花紫薇生长发育中光合效率的影响,以大花紫薇种子为试验材料,以不同60Co-γ射线辐射剂量(0、20、60、100、140、180 Gy)进行辐射处理,测量不同处理生长发育过程中叶绿素及光合指标的变化,研究其对紫薇光合系统的影响。结果表明:20、60 Gy处理较对照和其他处理叶绿素质量分数更高,更有利于叶片进行光合作用;60、100 Gy处理较对照和其他处理潜在光合速率和最大光合效率更好;各时期光合性能指数与综合性能指数均呈现先上升后下降的趋势,但随时间的增加整体呈现下降的趋势,60 Gy较其他处理性能指数高。由此得出,60 Gy辐射处理有利于大花紫薇光合色素的产生与积累,较好的增加电子传递效率,有利于光合系统的运转和能量的积累。     

基于Labview的植物红光吸收动态监测

为了动态监测植物生长过程中对红光的吸收，提出了一种基于Labview光频转换接收探头透射法实时监测植物红光吸收的检测方案，该方案属于无损检测，具有操作安全、简便的特点。     

原子吸收光谱法检测大蒜制品中微量元素锗

[目的]研究不同大蒜制品中锗元素含量的差别。[方法]采用马弗炉灰化样品,火焰原子吸收光谱法测定以金乡紫皮蒜为原料加工而成的黑蒜、蒜蓉辣酱、脱水蒜片、蒜粉、糖醋蒜5种制品中锗的含量。[结果]试验表明,黑蒜中锗含量为1.384 mg/g,蒜蓉辣酱中锗含量为0.784 mg/g,脱水蒜片中锗含量为0.913 mg/g,蒜粉中锗含量为0.956 mg/g,糖醋蒜中锗含量为0.827 mg/g。5种蒜制品中均含有锗元素,其含量由多到少依次为黑蒜、蒜粉、脱水蒜片、糖醋蒜、蒜蓉辣酱。[结论]研究可为大蒜及大蒜制品的开发利用提供参考依据。     

Exogenous CaCl2 reduces salt stress in sour jujube by reducing Na+ and increasing K+, Ca2+, and Mg2+ in different plant organs

In this study, we investigated the effects of 10 mM CaCl₂ on membrane permeability, malondialdehyde (MDA), reactive oxygen species (ROS), and Na⁺, K⁺, Ca²⁺, and Mg²⁺ concentrations in different organs of sour jujube grown under 150 mM NaCl stress. Our results showed 73% leaf wilting in the Na treatment. The Na treatment significantly increased leaf superoxide (O₂^.?) production rates, hydrogen peroxide (H₂O₂) concentrations, cell membrane permeability, MDA concentrations, and Na⁺ concentrations in roots, stems, and leaves. The Na treatment significantly reduced K⁺, Ca²⁺,and Mg²⁺ concentrations in roots, but increased K⁺ concentrations in stems. Compared with the Na treatment, 39% of the leaves showed wilting symptoms in the Na+Ca treatment. The Na+Ca treatment significantly decreased leaf O₂^.? production rates, H₂O₂ concentrations, cell membrane permeability, and MDA concentrations. Moreover, the Na+Ca treatment (1) significantly reduced Na⁺ concentrations in roots, stems, and leaves; (2) significantly increased root K⁺ concentrations; (3) significantly increased K⁺/Na⁺ ratios in roots; (4) significantly increased Ca²⁺ concentrations in stems and leaves, and Mg²⁺ concentrations in roots. In conclusion, exogenous CaCl₂ reduces NaCl stress in sour jujube by reducing Na+ concentrations and increasing K⁺, Ca²⁺, and Mg²⁺ concentrations in various plant organs.     

不同合成树脂工艺对改性材性能影响研究

为研究树脂对改性材性能的影响，采用2种不同工艺合成三聚氰胺-脲醛树脂（MUF），测试了树脂的相关性能。结果表明，不同合成工艺路线下制备的 MUF 树脂在固体含量、粘度、固化时间、游离甲醛含量间存在显著差异。最终树脂的分子结构类型相似性极高，但相同结构组分在不同树脂中所占比例各有差异。羟甲基基团在MUF2中所占比例高，而亚甲基桥键及醚键在MUF1中含量高。MUF1改性材的增重率（weight percent gain，WPG）值更大，但MUF2改性材的抗溶胀性（anti-swelling efficiency，ASE）和体积膨胀率（bulking rates，B）更高，MUF2改性材的尺寸稳定性更好。     

An evaluation of the net radiation sub-model in the ASCE standardized reference evapotranspiration equation: Implications for evapotranspiration prediction

Net radiation (R_n) is a key component of the surface energy balance, but it is expensive and difficult to measure accurately. For these reasons, R_n is often predicted in evapotranspiration (ET) calculations with a model requiring measurements of incoming shortwave radiation, air temperature, and vapor pressure. We compared R_n predictions from the R_n sub-model used in the American Society of Civil Engineers (ASCE) standardized reference ET equation to mean R_n measurements from five 4-component reference net radiometers. The radiometers were part of a recent comparison study of multiple net radiometer models conducted over irrigated and clipped turfgrass in northern Utah (Blonquist et al., 2009). In the R_n model, net shortwave radiation is determined by direct measurement of solar radiation and an assumed value of albedo for the surface (0.23 for fully vegetated surfaces), and net longwave radiation is calculated with a Brunt (1932, 1952) approach for predicting net surface emissivity, calculated from near surface vapor pressure. Additionally, the ratio of measured incoming shortwave radiation to predicted clear-sky shortwave radiation is used as a surrogate variable for cloud cover in the net longwave radiation calculation. Relative to the reference R_n measurements (average of five 4-component net radiometers), modeled R_n was high during the day by an average of 8.6% and high in magnitude (more negative) at night by an average of 13.4% over hourly time intervals. Daily total R_n calculated by summing the hourly model predictions was always higher than the reference measurements, by an average of 8.1%, whereas daily total R_n calculated from the model over daily time intervals was closer to the reference measurements, 2% high on average. The model R_n error during the day was partly caused by the assumption in the model that surface albedo is a constant value of 0.23. Measurements showed albedo ranged from approximately 0.21 at solar noon to 0.30 near the beginning and end of the day, with a mean value of 0.23. However, most of the model R_n error was due to the prediction of net longwave radiation, where the empirical equation in the model typically yielded values that were too low in magnitude (less negative), by approximately 20% on average, but the error was dependent on time of day. The R_n error at night was largely caused by the inability to measure the surrogate for cloud cover at night, which relies on measurement of solar radiation from a previous time period of sufficient solar zenith angle. All five of the net radiometer models tested in the comparison study matched the mean of the reference net radiometers better than the ASCE model. When modeled hourly R_n was used to calculate ET over hourly time intervals, or when hourly ET values were summed to yield daily ET, ET was typically high, by 6% on average, relative to ET calculated from measured reference R_n. When modeled R_n was calculated over daily time intervals and used to calculate ET over daily time intervals, ET was more accurate, 1% high on average, relative to ET calculated over daily time intervals from measured reference R_n. While new models for R_n are being developed, the sub-model in the ASCE standardized reference ET equation has been in use for the past two decades in thousands of ET stations. As newer models are developed we hope to use this data set to evaluate them.     

Contribution of incident solar radiation on leaves and pods to soybean seed weight and composition

The weight and composition of soybean seeds (Glycine Max L. Merrill) depend on changes in carbon and nitrogen assimilate supply during grain filling. Soybean pods and seeds are green, evidencing their capacity to capture light. However, the current physiological knowledge does not consider any effect of incident solar radiation reaching the pods on seed weight and composition. The objective of this work was to investigate the response of seed weight and composition to changes in assimilate supply from leaves, to the incident solar radiation reaching the pods and to the combination of both, changes in assimilate supply from the leaves and incident solar radiation on pods of soybean plants. Field experiments were performed during two growing seasons at Balcarce, Argentina. Treatments modified the amount of assimilates supplied by the leaves (plant shading, defoliation), the solar radiation reaching the pods (pod shading) or both (defoliation and pod shading) during seed filling. Plant shading and defoliation reduced seed weight, oil concentration and oil and protein content and increased the concentration of saturated and poli-unsaturated fatty acids while reduced oleic acid percentage. Pod shading increased the concentration of stearic acid and reduced the concentration of linolenic acid. When pods were shaded on defoliated plants, seed weight and oil and protein content decreased while fatty acid composition was similar to values obtained under defoliation treatment. Based on these results, a conceptual model that considers photoheterotrophic nature of reproductive structures of soybean is proposed. Seed weight, oil and protein content and oil fatty acid composition depended on assimilate availability for the seeds. The response of oil and protein content to assimilate supply depended on whether leaves were present or not. The effect of solar radiation incident on pods depended on the amount of assimilates available for the seeds: (i) when carbon allocated was low (defoliation treatments), pods contributed to seed carbon economy but solar radiation incident on them did not affect fatty acid composition; (ii) when carbon allocated to the seeds was high (intact plants), contribution of pods to seed carbon economy was not significant, but the amount of solar radiation incident on pods produced significant changes in fatty acid composition.     

硼对平邑甜茶幼苗硝态氮吸收、利用及分配特性的影响

以平邑甜茶幼苗为试材,运用~(15)N同位素示踪和非损伤微测技术,研究了不同供硼(硼酸0、1.0、2.0、3.0、4.0、5.0和6.0 mg·L~(-1))水平对平邑甜茶根系生长及氮素吸收、利用和分配特性的影响。结果表明,3.0 mg·L~(-1)硼酸处理的幼苗根系活力及根系形态指标显著高于其他处理,幼苗的全氮量及~(15)N吸收量增幅最大,分别比对照提高了19.4%和75.0%。随供硼水平的增加,植株氮素利用率呈现先增高后降低的趋势,在3.0 mg·L~(-1)硼酸处理时最大,为14.8%,是对照的1.8倍。施硼处理对幼苗的~(15)N分配率有一定的影响,3.0 mg·L~(-1)硼酸处理的根系~(15)N分配率达到最大,且显著高于对照。非损伤微测结果显示,3.0 mg·L~(-1)硼酸处理时,平邑甜茶根系对NO_3~-有强烈吸收且内流速度达到最大,在缺硼和高硼(硼酸0和6.0 mg·L~(-1))处理时有明显外排趋势。因此,3.0 mg·L~(-1)硼酸处理最有利于平邑甜茶根系的生长、根系活力的提高和氮素的吸收利用,而低硼和过量供硼均会抑制根系生长及氮素的吸收利用。     

锡林浩特地区太阳紫外辐射分析

为进一步揭示紫外辐射的变化规律,更好地为生产和人们的生活服务,基于锡林浩特国家气候观象台2007—2012年太阳紫外辐射观测资料,运用数理统计学方法与SPSS 11.5软件,分析了锡林浩特地区不同云况条件下太阳紫外辐射规律及与气象要素的相互关系。结果表明:太阳紫外辐射存在明显的日、季、年变化规律。一日内早晚小,中午大。一年内最高值出现在6—8月,最低值出现在11—12月。且与太阳总辐射、光合有效辐射、空气温度、空气湿度、地温0~5 cm存在较显著的相关性。目前锡林浩特地区紫外辐射强度(UV-B)1—3、10—12月最大值范围分别为0.20~1.91、0.13~1.43 W/m~2,低于人和动物的安全标准2 W/m~2,4—9月可出现最大值范围为2.02~3.39 W/m~2,容易对人和动物造成威胁和伤害。     

Influence of Soil Particle Size on the Measurement of Sodium by Near-Infrared Reflectance Spectroscopy

This study evaluates the effect of soil particle size (SPS) on the measurement of exchangeable sodium (Na) (EXC-Na) by near-infrared reflectance (NIR) spectroscopy. Three hundred thirty-two (n = 332) top soil samples (0–10 cm) were taken from different locations across Uruguay, analyzed by EXC-Na using emission spectrometry, and scanned in reflectance using a NIR spectrophotometer (1100–2500 nm). Partial least squares (PLS) and principal component regression (PCR) models between reference chemical data and NIR data were developed using cross validation (leaving one out). The coefficient of determination in calibration (R²) and the root mean square of the standard error of cross validation (RMSECV) for EXC-Na concentration were 0.44 (RMSECV: 0.12 mg kg^–1) for soil with small particle size (SPS-0.053) and 0.77 (RMSECV: 0.09 mg kg^–1) for soils with particle sizes greater than 0.212 mm (SPS-0.212), using the NIR region after second derivative as mathematical transformation. The R² and RMSECV for EXC-Na concentration using PCR were 0.54 (RMSECV: 0.07 mg kg^–1) and 0.80 (RMSECV: 0.03 mg kg^–1) for SPS-0.053 and SPS-0.212 samples, respectively.