Restoring of Growth Potential and Selection of Adaptative Cultivars of Mei Flowers in Nanshan Mountain,Chongqing

该文以３８０株衰弱梅树为研究对象，同时引进５５个梅花品种进行试验研究．从１９９１年底至１９９５年初，重新规划定植梅花７０６株，占地０．３７ｈｍ２，同时建立了品种圃，按梅花生物学特性进行科学管理．通过治理病虫、修剪、改土、加强肥水管理等一系列措施，使衰弱株恢复树势．在试验期内，连续进行生长势测定．所测衰弱株３００株的平均值为：树高达到２．３１ｍ，增高１．０２ｍ；冠径达到１．９６ｍ，增大１１９ｍ；干径达到２．１ｃｍ，增大１．１ｃｍ．品种株５０株平均值：树高达到２２９ｍ，增高０．６４ｍ；冠径达到１．７３ｍ，增大０．７７ｍ；干径达到２．８ｃｍ，增大０．９ｃｍ．这些数字表明树势普遍得到恢复，梅株基本无病虫，９０％开花．还从５５个品种中筛选出２２个适应本地环境条件生长的优良品种，以备推广．     

红外对流组合干燥小麦试验研究

设计了新型的红外热风组合谷物干燥机。该机采用先红外加热,再以热风对流排湿的干燥工艺。进行了不同对流风温、不同物料移动速度和有无红外辐射涂料为变动因素的小麦干燥正交试验。试验表明,在试验水平内,对流风温110℃、物料移动速度3.5cm/min和有红外辐射涂料时,物料降水幅度较大。试验中对流风温110℃的条件下,物料温度并未超过55℃,这与该机采用的干燥工艺有关。     

Individual- and scattered-tree influences on ultraviolet irradiance

Many of the potential effects of ultraviolet radiation (UVR)—damage to materials, altered herbivory of insects and activity of microbes, modified growth of vegetation, and adverse or beneficial effects on human health—are modified by the presence of trees that influence UVR exposure to various degrees. Though tree effects on total solar irradiance have been investigated often by measurements and modeling, tree influences on UVR, particularly in the ultraviolet B (UVB, 320–280 nm), differ substantially from tree influences on the rest of the solar spectrum, and thus the ratio of UVB to photosynthetically active radiation (PAR) is altered. Trees greatly reduce both UVB and PAR irradiance in their shade when they obscure both the sun and sky. Beneath dense forest canopies, relative irradiance (I_r=irradiancebeneath trees/above-canopy irradiance) for both UVB and PAR radiation may be 0.01–0.02. In the shade of a single tree, I_r on the horizontal in the PAR and total shortwave (SW) was about 0.1, whereas in the UVB and ultraviolet A (UVA, 320–400 nm), I_r was about 0.4. Conversely, where direct beam radiation came through gaps between crowns in a group of deciduous trees in winter, PAR I_r values averaged 0.95 and UVB I_r averaged only 0.41. In comparisons of minimum values of I_r on horizontal and the south-facing vertical surfaces in tree shade for UVB, UVA, SW, and PAR, where UVB I_r on the horizontal ranged from 0.22 to 0.62, depending on solar zenith angle, UVB I_r on the vertical ranged from 0.05 to 0.27. UVB I_r consistently exceeded UVA I_r on both the horizontal and vertical surfaces. PAR and SW I_r differed little between horizontal and vertical surfaces in tree shade. Modeled average I_r on the horizontal below a regular grid of ellipsoidal tree crowns was given byI_p=1−m−(θ^0.711/5.05)sin(πm), where m is fraction of area covered by tree crowns and θ is solar zenith angle. The tree influences will vary with pollutants in the boundary layer, which affect scattering of UVR.     

Angular distribution of radiation beneath forest canopies using a CCD-radiometer

An astronomical digital camera is equipped with a fish-eye lens and exchangeable filters to study the fine angular structure of radiation field in forests in the red and near infrared (NIR) spectral bands. A few examples of the angular distribution of downward radiances in conifer and broadleaf forests are given. The results of field measurements are compared with the spectral flux measurements by a field radiometer and with the calculations of radiance by a combined geometric-optical/radiative transfer (RT) model. The test measurements demonstrated that the hemispheric-view imaging radiometer is a good tool to validate canopy RT models.     

Effects of transuranic (239Pu, 239Np, 241Am) elements on soil fauna

Summary The ecological after-effects of soil pollution by the transuranic elements ²³⁹Pu and ²⁴¹Am were studied in field experiments using soil animals as bio-indicators of radioactive pollution. In a long-term field experiment with ²³⁹Pu in chernozem soils an obvious decrease in soil macrofaunal populations was apparent after 3 years. The population density of earthworms and insect larvae had halved, and that of microarthropods had decreased by a factor of 5.5. After 18 years the major portion of ²³⁹Pu had been transformed to ²⁴¹Am and the population density and species diversity in the polluted plots did not differ from those in the control plots, although there were differences in spatial distribution. In experiments with ²⁴¹Am, the soil pollution effect had decreased 1 year after exposure. The accumulation of ²³⁹Pu, ²³⁹Np, and ²⁴¹Am in earthworm body tissues was studied in laboratory experiments. The maximum concentrations of ²³⁹Pu and ²⁴¹Am in earthworms were recorded after 7 days, and for ²³⁹Np after 3 days. The dynamics of ²³⁹Pu, ²³⁹Np, and ²⁴¹Am accumulation by three earthworm species were studied over 1–65 days and doses of irradiation from the incorporated radionuclides and gut soil radionuclides were determined.     

Making sense of yield trade-offs in a crop sequence: A New Zealand case study

Crop growth is driven by the capture and utilisation of solar radiation. The most productive crop sequences are those that maximise the interception and use of solar radiation. However, there are yield trade-offs because of the timing of transitions between successive crops. A longer duration of one crop will mean that the following crop is sown later and will therefore produce a lower yield. Maximising the yield of a sequence involves a compromise between the yields of successive crops. We describe a case study of a forage cropping rotation in New Zealand, demonstrating how simulation models can be used to define the best compromise between the yields of successive crops, and thereby maximise the total yield of the full sequence.A case study using a series of long-term simulation experiments for four diverse environments in New Zealand was undertaken in a continuous, summer maize - winter cereal, cropping sequence. Maize sowing dates and hybrid durations, and cereal sowing and harvest times were varied systematically. The actual simulated crop and sequence yields varied from site to site, but there was a consistent trend identifying the most productive combinations of sowing date and hybrid duration. The sequence of comparatively late sowing date of maize (1 December) and a long-season hybrid maximised the total yield of the sequence. The highest sequence yields were achieved by balancing the need to capture a high level of annual solar radiation and the need to have a large proportion of solar radiation captured by maize, which has the greater RUE in summer. This analysis illustrates how crop simulation models can be used to design and understand the processes that give the most productive cropping sequences.     

五个常见日太阳总辐射模型在华北地区的有效性验证及分析

在地学、农学等领域,日总辐射量是一个很重要的参数,但相比常规气象观测站,全球辐射观测站的数量却很少,因此,太阳辐射的估算一直受到重视。本文在分析比较前人建立的太阳总辐射模型的基础上,选取较常见且有代表性的5个模型：Angstrom-Prescott模型（I）、Ogelman模型（II）、Bahel模型（III）、日照百分率和气温日较差综合模型（IV）和刘可群等模型（V）。用华北地区6个代表站点2001-2010年的逐日太阳总辐射观测数据,按照整个分析期（10a）、不同季节、不同天气3种情况,对5个模型模拟的效果进行对比与分析。结果表明：（1）5个模型在各代表站点模拟的逐日太阳总辐射值与该站实测值间具有极显著的正相关关系（P≤0.01）,相关系数（R）均在0.93以上,平均绝对误差（MAPE）均在9.68%～17.56%,归一化均方根误差（NRMSE）在12.47%～23.12%,模拟结果大多为“好”,个别为“可以接受”,说明5个模型及相应的系数适合估算华北地区日太阳总辐射。（2）分析期内,5个模型在6个站点的MAPE平均值分别为14.28%、14.93%、12.78%、12.27%、13.01%,相应的NRMSE平均值分别为18.80%、19.71%、17.09%、16.27%、17.24%,模拟结果为“好”,其中模型IV误差最小,但与模型III和V无显著差异。（3）模型I-V的MAPE平均值在春季依次为11.97%、12.19%、11.17%、10.86%、11.24%,相应的NRMSE平均值依次为15.46%、15.75%、14.27%、13.95%、14.27%;夏季MAPE平均值依次为14.46%、15.47%、13.32%、12.45%、13.36%,相应的NRMSE平均值依次为18.89%、20.21%、17.21%、16.22%、17.05%;秋季MAPE平均值依次为14.81%、15.65%、12.67%、12.19%、12.20%,相应的NRMSE平均值依次为18.94%、20.00%、16.66%、15.94%、15.95%;冬季MAPE平均值依次为18.08%、18.56%、15.19%、14.99%、14.11%,相应的NRMSE平均值依次为22.52%、23.28%、19.42%、19.06%、18.31%。总体上,四个季节的模拟结果大多为“好”,个别为“可以接受”;春、夏、秋季,模型IV误差最小;在冬季模型V最小,模型IV次之。（4）模型I-V的MAPE平均值,在有日照时,依次为11.23%、12.03%、9.52%、9.32%、9.94%,相应的NRMSE平均值依次为14.92%、15.92%、12.75%、12.44%、13.13%。模拟结果均为“好”,其中模型IV误差最小;无日照时,MAPE平均值依次为49.25%、47.92%、49.71%、46.03%、45.51%,相应的NRMSE平均值依次为61.92%、62.09%、61.89%、58.02%、55.70%,模拟结果均为“不好”。综合分析可知,5个模型均可用于估算华北地区日太阳总辐射,但模型IV即日照百分率和气温日较差综合模型精度最高。     

辣椒叶片DNA提取方法的优化

对提取植物DNA的CTAB法进行了改进.使用Retsch研磨仪极大地提高了效率,并在CTAB提取液中添加0.2%的二硫苏糖醇可以有效防止酚类物质的氧化及与DNA的不可逆结合.紫外吸收检测DNA A260/A280=1.7～1.8;经琼脂糖凝胶电泳检测得到一条带型较宽且清晰的DNA谱带,辣椒叶片DNA平均产量为29.8μg/100 mg,证明所提取DNA的质量和得率均较高;酶切结果表明DNA质量较高,能够酶切完全;PCR扩增到的特异性条带明亮、整齐,基本无拖尾,达到各种分子标记等研究技术的要求.