基于格网的GCM数据修订分析未来海南岛农业水热资源的变化特征

以海南岛为研究区域，选用5个大气环流模式（GCMs）1970−1999年的逐日输出数据和同期地面气象观测数据，使用空间插值降尺度到0.5°×0.5°格网。以格网单元为基础，应用系统误差修订（修正值法或比值法）和多模式集合平均方法（贝叶斯模型平均法BMA或等权重平均法EW），训练与验证GCMs输出值并进行综合修订。在此基础上，分析RCP2.6、RCP4.5和RCP8.5情景下，未来海南岛近期（2020−2059年）和远期（2060−2099年）农业水热资源，包括年平均气温、1月平均气温、≥10℃积温、≥20℃积温、年降水量、1月降水量和≥20℃界限温度生长期间降水量的变化特征。结果表明：GCMs输出值的系统误差和BMA权重系数在格网间存在较大的空间差异，且GCMs输出值低估逐日最高气温约3.55℃，高估逐日最低气温约1.19℃，逐日降水量仅为观测值的54.35%。基于格网的综合修订，可有效降低GCMs输出值在空间上的不确定性，BMA与EW的修订结果相似，均优于单一GCM模式。通过格网BMA综合修订后，最高气温、最低气温和降水量在验证期的相关系数r分别约提升0.10、0.07和0.06；均方根误差RMSE分别约降低2.38℃、1.01℃和1.01mm；较单一GCM相对观测值的偏差平均约减少3.25℃、1.13℃和25.67mm。未来海南岛农业热量资源在空间上主要表现为从中部向外围逐渐升高，高温主要分布在南部至西部沿海地区，年平均气温的增幅全岛较为接近，1月平均气温、≥10℃积温和≥20℃积温的增幅分别表现为由东向西、由北向南和由中部向外围递减。在时间上，RCP8.5情景下所有农业热量资源均为极显著增加且增温最快，RCP4.5情景为先增加后平缓，RCP2.6情景较为平缓，远期无显著增温。未来海南岛降水资源在空间上转为由东向西逐步递减的格局，南部和北部沿海地区降水变率增加，西部和中部降水变率减少，在时间上无显著变化趋势。随着未来海南岛气候变暖和降水格局的改变，农作物适宜种植面积扩大，会对农业生产带来巨大挑战，应提前布局，做好趋利避害。     

Leaf carbohydrates assimilation and metabolism affect seed yield of rapeseed with different waterlogging tolerance under the interactive effects of nitrogen and waterlogging

Waterlogging is a main factor causing rapeseed (Brassica napus L.) yield loss, and reasonable nitrogen (N) applications can compensate for this loss. To investigate the effects of N rates on seed yield of waterlogged rapeseed, the waterlogging-tolerant rapeseed variety ZS 9 and sensitive variety GH01 were waterlogged for 0 and 10 days with five leaves at the seedling stage under four N rates (0, 90, 180 and 270 kg/ha). Waterlogging significantly decreased seed yield, while N application can alleviate the yield loss. The yield decrease rate of waterlogged GH01 was greater than that of ZS 9 under the same N rate. During the seedling and bolting stage, the leaf photosynthetic rate (Pn) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity increased, while activities of adenosine diphosphate glucose pyrophosphorylase (AGPase), sucrose synthase (SuSy) and sucrose phosphate synthase (SPS) decreased with more N under the same watering conditions. Compared to the plants without waterlogging, the leaf Pn and Rubisco activity, starch and sucrose contents of waterlogged rapeseed decreased at the two stages; activities of AGPase, SuSy and SPS of waterlogged rapeseed decreased at the seedling while increased at the bolting stage for both the two varieties. At the flowering stage, the Pn, the activities of Rubisco, AGPase, SuSy, SPS and contents of sucrose, starch increased with more N application for both ZS 9 and GH01. Compared to the plants without waterlogging, the Pn and Rubisco activity for waterlogged plants of the two varieties increased; the waterlogged plants of tolerant variety had higher activities of AGPase, SuSy and SPS, while those of sensitive variety was significantly lower. However, the decreased starch and sucrose content were found in both tolerant and sensitive varieties. The activities of AGPase, SuSy and SPS at flowering were highly positively correlated with yield under the interactive effects of N and waterlogging. These results suggested that the flowering stage is the most important stage that N had the positive regulation on waterlogged rapeseed growth. The carbohydrates translocation from leaves to seeds of the tolerant variety were enhanced after waterlogging, while that of the sensitive variety was still inhibited. This was the main reason for the difference in yield between the two waterlogged varieties.     

基于P-S-R框架模型试点研究高寒地区生态承载力——以甘肃省迭部县为例

全面客观评价生态资源承载能力,进而为区域可持续发展提供理论依据。以甘肃省迭部县为例,首先,采用压力-状态-响应(P-S-R)模型构建生态承载力评估指标体系,运用层次分析法(Analytic Hierarchy Process,AHP)确定各指标权重,评估生态环境承载力现状;其次,在生态功能区层面对迭部县水源涵养功能及生物多样性功能进行评价;最后,对生态承载力状况进行成因解析。研究结果表明：（1）迭部县整体生态承载力得分为0.239,处于“较强”承载力状态,构成整体生态承载力的生态弹性力、资源和环境承载力和人类社会影响力得分分别为0.222、0.062和0.063。（2）2016年,迭部县单位面积水源涵养量为111.76 mm,水源涵养功能处于“高”状态,其中,水源涵养功能较高地区主要集中在以草地和针阔混交林为主的区域。（3）自然栖息地面积占迭部县总面积的83.67%,其自然栖息质量指数(Natural Habitant Quality Index,NHQI)处于“高”状态。（4）从自然和经济2个因素进行分析,发现迭部县生态环境条件较好,但林草地面积已呈现出逐渐减少状态,因此需要通过合理科学的开发引导,发展文化旅游事业,推动迭部县的可持续发展。     

Comparison of the microbial communities of alpacas and sheep fed diets with three different ratios of corn stalk to concentrate

The objective of this study was to investigate the characteristics of ruminal microbial communities of alpacas (Lama pacos) and sheep (Ovis aries) fed three diets with varying ratios of roughage (corn stalk) to concentrate, 3:7 (LS), 5:5 (MS) and 7:3 (HS). Six alpacas (one-year-old and weighing 29.5 ± 7.1 kg) and six sheep (one-year-old and weighing 27.9 ± 2.7 kg) were used in this study, in a replicated 3 × 3 Latin square experiment. Total protozoa concentration was determined under the microscope; total fungi and methanogens were assessed using quantitative polymerase chain reaction and expressed as a percentage of total bacterial 16S rRNA gene copies; bacterial communities were investigated by targeted 16S rRNA gene (V3–V4 region) sequencing. The percentage of fungi was significantly higher in alpacas than in sheep under the LS diet, while the concentration of protozoa was significantly lower in alpacas under HS, MS and LS diets. The alpha diversity including Shannon, Chao l and ACE indices of bacterial communities was higher in alpacas than in sheep, under the LS diet. A total of 299 genera belonging to 22 phyla were observed in the forestomach of alpaca and sheep, with Bacteroidetes and Firmicutes dominating both animal species. Phyla Armatimonadetes and Fusobacteria, as well as 64 genera, were detected only in alpacas, whereas phyla Acidobacteria and Nitrospira, as well as 44 genera, were found only in sheep. The abundance of cellulolytic bacteria, including Butyrivibrio and Pseudobutyrivibrio, was higher in alpacas than in sheep under all three diets. These differences in the forestomach microbial communities partly explained why alpacas displayed a higher poor-quality roughage digestibility, and a lower methane production. Results also revealed that the adverse effects of high-concentrate diets (70%) were lesser in alpacas than in sheep.     

捕食线虫性真菌的分离培养及分布规律

对自然界中的捕食线虫性真菌进行了分离和种属区分，并对分布规律进行了研究。从土壤、粪便等材料中获得了2类活性较强的捕食线虫性菌株：即套捕型(hooping)捕食线虫性真菌和粘捕型(sticking)捕食线虫性真菌。主要的代表种类有3种。这些捕食线虫性真菌在捕食性结构分生孢子形态及某些生物学特性上有一定差异。套捕型捕食线虫性真菌代表种为少孢节丛孢菌(Arthrobotrys oligospara)和梨形指环菌(Dactylaria pyriformis)，它们以菌环、菌网作为捕食性结构(器官)，以套捕方式杀灭线虫幼虫。梨形指环菌可产生多量厚垣孢子(chlamyalospore)。粘捕型捕食线虫性真菌代表种为纺锤隔指孢菌(Dactylella ellipsospora)。可形成菌结捕食线虫性结构，以粘捕的方式杀灭线虫幼虫。结果表明：捕食线虫性真菌在土壤和家畜粪便中的分离率是40．41％；此类菌适合于生存在阴暗、潮湿、富含腐植质的环境中。在温暖季节时，采用0．4g／L玉米粉琼脂培养基(CMA)易于对其进行分离培养。     

水霉属菌(Saprolegnia)分离培养技术研究

 对水霉(Saprolegnia)的分离培养技术进行了探索,筛选出大麻籽、油菜籽、红花籽、苍蝇、蚜虫、小麦粒、玉米片、茶叶、葵花仁9种材料作为诱发水霉菌的诱饵。其中油菜籽能防止腐霉菌(Pythium)污染,是初步纯化菌种、排除杂菌的适宜饵料。同时发现控制温度能使水霉在最短时间内分别产生无性或有性繁殖。在水培条件下,25℃左右适合菌丝及无性器官的发育,有性器官却不能产生,而只有在15~17℃条件下才能使水霉很快进入有性生殖阶段;在加入200mg/L链霉素的CMA培养基上促发有性阶段则需要在25℃左右的温度下进行,方能缩短培养时间。     

群钻钻削精度试验

通过群钻钻头直径Ｄ，进给量ｆ和切削速度ｎ对孔径扩张量，圆度，孔中心线垂直度和直线度影响的试验，得出它们的变化规律。