Evaluation of proline analysis and chlorophyll fluorescence quenching measurements as drought tolerance indicators in durum wheat (Triticum turgidum L. var. durum)

Summary The possibility of using proline accumulation and fluorescence inhibition as predictive tests for drought tolerance in durum wheat has been investigated. The drought susceptibility of 25 genotypes was evaluated by comparing yields and yield components in irrigated and non irrigated conditions in the field. A drought susceptibility index (DSI) was calculated based on yields from irrigated and dry treatments and compared with the results obtained using the two physiological criteria. Proline accumulation and chlorophyll fluorescence inhibition were found to be significantly and negatively correlated with DSI of grain yield, biological yield, and thousand kernel weight, and tiller index. The use of both criteria for breeding durum wheat in Mediterranean dryland is discussed.     

基于超高压水切割法的木制工艺品加工参数优选与分析

在我国木材加工领域,数控超高压水射流技术的应用尚处于起步阶段,多用于珍贵木材的切割。为优化水切割在木材加工领域中的应用,笔者将中密度纤维板和意杨实木作为试验材料,采用正交试验法,以调砂速度、气干密度、水切割压力、进给速度、靶距工艺参数作为对其加工表面粗糙度的影响因素。利用数控工作系统设计CAD图案后进行的水切割试验,并通过对试件表面粗糙度的测量和相关计算,得到各工艺参数影响显著度程度及其最优方案。该研究对花式木地板及其木刻、木结构室内装饰板、红木家具等木制工艺品的加工领域提供工艺参数优选,具有较高的应用价值和现实意义。     

黄土沟壑区切沟植被的激光点云滤波及地形构建

为了获取黄土沟壑区切沟的高精度地面高程模型(DEM),该文针对其植被特点,提出一种基于激光回光强度衰减模型的植被滤波方法。首先建立回光强度随距离的衰减模型,通过得到的衰减系数,对点云作回光强度补偿。其次提出融合回光强度的自适应分块拟合法,在Matlab7.6中对甘肃天水桥子沟切沟点云数据应用该方法进行滤波。滤波后植被点数为160 517,占点云总数的34.04%。对比滤波前后切沟数据,地面点集的高程均方根误差由0.1430降到0.1324,滤波后等高线毛刺基本消除,地面特征保持良好。对比该文方法、回光强度分类法、曲面拟合法的均方根误差分别为0.1324、0.1398、0.1412,说明该文方法降低了切沟DEM的误差。通过计算滤波前后DEM高程差的累积概率,得到桥子沟试验区一条典型切沟的植被盖度分布,沟底植被平均盖度为0.274,左侧A区和右侧B区沟壁植被平均盖度分别为0.802、0.583,得出了右侧沟壁侵蚀速度明显大于左侧且沟头前进速度较快的结论,与2002-2012十年间该切沟实际调查资料对比,沟长增长213.6%,沟宽仅增长83%,一定程度说明植被降低了沟壁的侵蚀速度。试验表明该方法适用于黄土沟壑区切沟点云的植被滤波处理,为建立高精度切沟DEM、切沟的发育监测和水土流失治理提供科学依据。     

北京市气候变化对奶牛热冷应激的影响

气候变化对奶牛养殖的影响日益凸显,一些地区奶牛养殖的热应激或冷应激外部环境有所加剧。该文采用温湿度指数（temperature humidity index,THI）和风寒温度（wind chill temperature,WCT）2个指标,分析了北京地区1951－2012年逐日的THI和WCT的变化特征,重点分析了气候变化对奶牛养殖应激环境变化规律的影响。结果表明：近62 a来北京地区温度提升了1.93℃,气候变暖特征明显快于全国,气候变化加剧了北京地区热应激温度环境,降低了冷应激温度环境,综合考虑相对湿度和风速等气象因素,气候变化对北京地区热应激综合环境影响小,对冷应激综合环境影响大。但值得关注的是,2008年以来,北京地区热冷应激环境呈现"双升"态势,尤其冷应激环境明显增强,2012年冷应激天数为近10 a来最高,对北京地区的奶产量产生了不利影响。研究结论对以开放或半开放式牛舍养殖为主的北京地区的牛舍改造和应激设施设备改善提供了科学决策依据。     

基于对象的方法(优于像素法)对巴西大西洋雨林地区的一个保护区进行土地覆盖分类

Conventional image classification based on pixels hinders the possibilities to obtain information contained in images, while modern object-based classification methods increase the acquisition of information about the object and the context in which it is inserted in the image. The objective of this study was to investigate the performance of different classification methods for land cover mapping in the vicinity of the Alto Ribeira Tourist State Park, a Brazilian Atlantic rainforest area. Two classification methods were tested, including i) a hybrid per-pixel classification using the image processing software ERDAS Imagine version 9.1 and ii) an object-based classification using the software eCognition version 5. In the first method, six different classes were established, while in the second method, another two classes were established in addition to the six classes in the first method. Accuracy assessment of the classification results presented showed that the object-based classification with a Kappa index value of 0.8687 outperformed the per-pixel classification with a Kappa index value of 0.2224. Application of the user’s knowledge during the object-based classification process achieved the desired quality; therefore, the use of inter-relationships between objects, superclasses, subclasses, and neighboring classes were critical to improving the efficiency of land cover classification.     

联合Terra/Aqua MODIS多角度多光谱数据反演冬小麦叶面积指数

Terra与Aqua双星搭载的MODIS传感器可实现每日上下午分别对同一地点观测一次,并且由于卫星轨道漂移形成累积连续多天的多角度观测特点,加上多通道的光谱响应,极大地丰富了地表目标的观测信息,为LAI等地表参数的实时准确反演提供了可能。该文利用MODIS双星高质量的连续多天的多波段地表反射率数据,结合PROSAIL(PROSPECT+SAIL,properties spectra+scattering by arbitrarily inclined leaves)模型和查找表方法反演冬小麦LAI,并与MODIS LAI产品及野外采样点实测LAI对比,结果表明,联合双星高质量的多角度多波段数据能够较准确反演冬小麦LAI,其反演结果无论从空间分布还是时序变化特征来讲,较MODIS LAI产品更符合实际情况,也更接近地面实测值。该文的研究为充分利用MODIS数据的角度和光谱信息反演小麦等农作物的LAI提供了一定的借鉴。     

Spatial distribution pattern changes of oasis soil types in Manasi River Basin,arid northwestern China

Soil distribution pattern play a significant role in the stability conservation and economic development of oasis in arid regions. Hence, ecologists and agrology scientists have a central interest in understanding the spatial distribution changes of soil types. The aim of this study was to analyze the main processes of soil distribution pattern changes from 1987 to 2006 through the landscape indexes. Soil types and soil distribution pattern changes were assessed and compared by using two soil maps made in 1987 and 2006. 14 soil types were classified and analyzed in the study area. Results indicated many differences among the changes of different soil types. During the period from 1987 to 2006, there were widespread changes in spatial distribution of soil types in Manasi River Basin at class-level. The area of Petrocambids decreased, whereas Aquicambids increased. The small patches began to coalesce into large ones and the patch numbers decreased during the past 20 years, which brought about the fragmentation decrease in Manasi River Basin. In contrast to the decrease of the patch density, the average patch area of 12 soil types increased. With the increasing man-made disturbance, more soil type patches, especially the agricultural soil patches were close to square in shape. During the recent 20 years, the decreased patch shape indexes occupied about 57% of all while the increased patch shape indexes were over 40%. The split index of most soil types has also declined during the same period. The landscape-level indexes also reflected the spatial distribution changes of oasis soil types. The landscape diversity index and landscape evenness index have increased while the landscape dominance index has decreased in the recent 20 years, which showed that more equirotal soil patches were formed and various soil types dominated the soil landscape in Manasi River Basin. Changes of different soil types are one of major indictors to show environment changes and impacts of human activities. Therefore, it is necessary to emphasize the study of soil type changes in the arid and semiarid region.     

土壤发育指标与气候因子的关系及辽西地区古气候重建

通过对我国现代气候条件下发育的22个土壤剖面发育指标的分析,运用相关性分析方法建立了土壤发育指标与气候因子的关系—转换函数,并将之运用于辽宁朝阳凤凰山古土壤剖面古气候参数重建中,得出71 ～423 ka BP以来的古气候参数值:403 ～423 ka BP期间年均降雨量为523.92 ～574.42 mm,年均温为10.6～11.0℃;311 ～403 ka BP期间年均降雨量为1 184.6 ～1 277.2mm,年均温为15.6～16.6℃;243～311 ka BP期间年均降雨量为517.24 ～669.08 mm,年均温为9.18 ～12.2℃;225 ～243 ka BP期间年均降雨量为1 302.7 mm,年均温为16.5℃;208 ～225 ka BP期间年均降雨量为642.54～731.42 mm,年均温为10.1～11.6℃;176～208 ka BP期间年均降雨量为1 231.4 mm,年均温为16.0℃;148 ～ 176 ka BP期间年均降雨量为640.49 ～682.09 mm,年均温为8.49 ～9.13℃;71 ～148 ka BP期间年均降雨量为1 128.2 ～1 294.0 mm,年均温为16.1 ～16.6℃.辽宁朝阳现今全年平均气温9℃,年均降水量450～ 500 mm,说明该地区42万年以来气候有过多次波动,但总的趋势是由温暖湿润向寒冷干旱演化.     

基于空间模型技术的拟人机械腿的运动学传递性能分析

为了弥补当前拟人机器人结构的不足和改善拟人机械腿的通用性和适应性。该文提出了一种拟人机械腿机构,并研究了该拟人机械腿的运动学传递性能。推导出该拟人机械腿的位置反解及运动传递平衡方程,定义了运动传递性能评价指标及大小腿的全域性能评价指标,在有限的空间图形中,分别研究了各结构参数(各主要杆件的长度及结构角度)与各全域线速度传递性能的评价指标、全域角速度传递性能的评价指标之间的分布规律。研究结果表明,各结构参数的取值越靠近中间值时,全域线速度传递性能的评价指标值较好,随着杆WE、杆ED与杆O1D的增加,全域角速度传递性能的评价指标值越好,随着杆OC、BC、DO1和GH的减小,全域角速度传递性能的评价指标值越好。该研究为此种拟人机械腿的进一步参数优化、轨迹规划及研制提供依据。     

湘潭农业生态系统的能值分析及其可持续性评价

为提高湘潭市农业生产力水平,促进农业生态系统可持续发展,运用能值分析理论和方法,对湘潭市2000—2008年农业生态系统的能值投入产出、运行效率、ELR进行定量分析。结果表明:湘潭市农业生态系统能值投入以可更新的有机能为主,主要依赖于人力,其所占能值比重由2000年的0.58下降到2008年的0.49,尚处于从传统农业阶段向现代农业阶段转变的过渡时期;能值产出中林业能值产出较大,而种植业和渔业所占比例较小,尤其是渔业,未达到整个能值产出的0.01%;湘潭市农业生态经济环境负载率低,资源空间利用未达到优化配置,具有较大的发展空间。湘潭农业生态系统的可持续发展指数变化较大,波动范围在0.03~0.11之间,说明湘潭农业生态系统属于消费型经济系统。应根据农业的需要合理调整农业产业结构及能值投入结构,促进农业生态经济系统的良性循环。