基于GIS的安塞县土壤水分制图及其数量分析   总被引：1，自引：0，他引：1  

焦峰  温仲明  陈云明  杨勤科  李锐 《中国水土保持科学》2006,4(1):75-80

 以空间图形和数据库为基础,利用GIS安塞县的土壤水分样点数据与地理数据结合起来,建立不同利用类型土地类型坡度分级的浮点型土壤含水率字段,对安塞县域尺度土壤水分制图及其定量化方法进行研究和探讨,对安塞县不同土层土壤水分状态和分布进行定量分析。结果表明:从土壤水分结构看,安塞县土壤水分总体上处于较低水平,0～500 cm土层平均土壤含水量在含水量为8.6%～10.8%的分布面积占到总土地面积的75.34%,在含水量<6.4%和6.4%～8.6%的分布面积占到总土地面积的19.36%,其中含水率<6.4%的土壤干层面积占到总土地面积的9.23%,其在上层分布面积大于下层,分布在一般（≥10.8%）以上水平的面积仅占总土地面积的5.31%。安塞县每2的土壤水库蓄水量在0～120cm土层仅有0.060.07 m3,而其他土层都在0.15m3以下。说明安塞县土壤水分环境极差,土壤水库的调节作用对于林木生长极其有限,大面积植树造林超越了安塞县土壤水库的供水和调水能力,是不适宜的;因此,在以适地适树原则适应土壤水分环境的同时,应加强土壤水分环境的改善。  相似文献   

加气对滴头堵塞行为的影响     

张二信  吕畅  张文倩  董爱红  王彦邦  牛文全 《排灌机械工程学报》2023,41(4):400-408

为探明加气滴灌下滴头堵塞规律及影响因素,选用4种不同特征参数(流量Q、最小断面尺寸min(W,D)和入水栅格面积M)的内镶贴片式滴头E1,E2,E3和E4,分别在加气(AI)和未加气(CK)条件下进行了滴头堵塞测试,并通过泥沙絮凝沉降试验对其结果进行了验证.结果表明:加气和滴头结构对滴头堵塞性能具有显著影响(P<0.05).加气加剧水中泥沙颗粒的絮凝沉降、加速絮凝颗粒在毛管内和流道入口的黏附、增大滴头入口发生突然堵塞风险是造成加气加剧滴头堵塞的主要原因;当选择入口尺寸较大的E4滴头时,其流道入口堵塞风险降低、流道内泥沙絮凝沉降速率减缓而表现出加气减缓滴头堵塞,而选择入口尺寸较小的E1—E3滴头时,其毛管内泥沙絮凝沉降速率增大、滴头入口堵塞风险增高而表现出加气加剧滴头堵塞.  相似文献   

新城疫病毒基质蛋白第23位苯丙氨酸对病毒复制与细胞致病性的作用     

高海岗  陆建荣  胡增垒  胡娇  刘晓文  王晓泉  朱杰 《中国家禽》2012,34(9):17-20

副黏病毒科的副流感病毒5型(Parainfluenza virus5,SV5)和腮腺炎病毒(Mumps virus,MuV)的基质蛋白(Matrix protein,M)都编码FPIV-like晚期结构域(Late-domain,L-domain),L-domain中的苯丙氨酸(Phenylalanine,F)对病毒出芽与复制有很重要的作用。新城疫病毒(Newcastle disease virus,NDV)M蛋白也包含潜在的L-domain23FPIV26,但23F对NDV的出芽及复制的作用尚不明确。本试验应用反向遗传学技术,以NDV ZJ1株为母本病毒,拯救一株M蛋白F23A突变的重组病毒ZJ1F23A,并在DF1细胞上对ZJ1F23A的复制性能和细胞致病性进行评价。结果显示,ZJ1F23A在DF1上的复制水平显著低于母本病毒ZJ1,ZJ1F23A对DF1的致病性比ZJ1弱。试验结果说明NDV M蛋白23F对病毒复制及病毒的细胞致病性具有重要作用。  相似文献   

Host preference and nymph performance of B and Q putative species of Bemisia tabaci on three host plants     

Xiaoguo Jiao  Wen Xie  Shaoli Wang  Qingjun Wu  Long Zhou  Huipeng Pan  Baiming Liu  Youjun Zhang 《Journal of pest science》2012,85(4):423-430

Host selection is central to understanding the evolution of the interaction between herbivorous insects and host plants. Most studies on host selection of herbivorous insects are focused on the optimal oviposition theory which posits that the herbivores preferentially oviposit on plants that provide optimal conditions for offspring development (preference–performance hypothesis). However, the positive correlation between female oviposition preference and offspring performance is not always observed. Here, we determined the relationship between whitefly settling and oviposition preference and nymph performance of B and Q putative species of Bemisia tabaci on three host plants, cotton Gossypium hirsutum L., tomato Lycopersicum esculentum Mill, and poinsettia Euphorbia pulcherrima Wild. We further investigated whether nutritional and defensive chemistry of the three host species shaped whitefly settling and oviposition preference of both putative species. Foliar chemistry differed significantly among the three host species. Compared to cotton and tomato foliage, poinsettia foliage was 8?% lower in nitrogen, 60?% higher in carbohydrate, and 90?% higher in phenolic compounds, respectively. When given a choice, B and Q putative species of B. tabaci preferred settling on nutritionally superior tomato, whereas both putative species preferentially oviposited on nutritionally inferior poinsettia. Nymph survivorship of B and Q putative species was substantially reduced and nymph developmental duration (egg-to-adult) was markedly prolonged on poinsettia relative to those reared on cotton and tomato. Therefore, our results are consistent with the optimal foraging theory, rather than the optimal oviposition theory. Females of B and Q putative species of B. tabaci preferentially ovipositing on poinsettia may be a trade-off between nymph performance and the avoidance of natural enemy.  相似文献   

桑菌根初生结构对梯度水分胁迫的细胞学生态响应     

叶娇  涂波  施松梅  杨晓红  黄先智  秦俭 《西南大学学报(自然科学版)》2012,34(8):067-072

为探索菌根桑在石漠化地区的生态修复和生态重建功能,采用0,10%,15%,20%,25%5种不同浓度的PEG6000溶液与培养基质混合,模拟自然条件下的土壤梯度水分胁迫生境,将接种丛枝菌根真菌玫瑰红巨孢囊霉的桑苗(F+)培养5个月后,挑选长势与未接种对照(F-)基本一致的植株分别移栽入备好的梯度水分胁迫基质中,胁迫8d后,石蜡切片观察初生根成熟区的细胞学特征.结果表明:桑树初生根成熟区由表皮、皮层和维管柱组成,表皮上有少量的根毛,内皮层明显,其上有凯氏带增厚,二原型维管束与初生韧皮部相间排列.水分胁迫时,0～10%PEG处理的F-根表皮存在,皮层薄壁组织发达,细胞饱满;15%～20%PEG时,表皮死亡脱落,皮层细胞开始失水、变形,随着PEG浓度的增大失水情况加剧,细胞扭曲、收缩变小;0～20%PEG时F+表皮存在,还可见少量根毛,25%PEG时,表皮死亡脱落,多数皮层细胞仍然近圆形、饱满;中柱中初生韧皮部最晚受到水分胁迫的影响,初生木质部受影响不显著.推测:F+桑苗对水分胁迫能力的提高主要是通过根外菌丝网络系统把根际以远更加广泛土壤中存在的水分吸收过来并由根内菌丝运送到皮层细胞,满足桑树根内和地上部分的水分需求,提高植株对高达-0.49Mpa水分胁迫的忍耐性,表皮延后脱落死亡,根皮层细胞正常形态更加持久.  相似文献   

印楝油两性不育灭鼠颗粒剂对小鼠摄食系数与抗生育作用     

石东霞  蒋忠荣  殷中琼  杨帆  贾仁勇  颜其贵  贺常亮  徐娇 《林业科学》2012,48(4):171-176

鼠害一直影响我国林业的发展,传统的灭鼠药物由于对环境的破坏过大且有长期毒副残留的危害,因而现有灭鼠制剂已逐渐开始向天然灭鼠剂转变,其中通过抗生育机制控制害鼠的繁殖力度是一  相似文献   

Seasonal changes in immunoreactivity of activin signaling component proteins in wild ground squirrel testes     

Sheng X  Zhang H  Zhang M  Zhang W  Hu X  Song M  Zhou J  Xu M  Weng Q  Watanabe G  Taya K 《The Journal of reproduction and development》2012,58(1):126-131

The seasonal spermatogenesis and localization of inhibin/activin subunits (alpha, betaA, betaB) in the testes of wild ground squirrel has been previously described; however, the expression pattern of activin receptors and cytoplasmic signaling SMADs has not been detected in any seasonal breeders. The objective of this study was to investigate the abundance and cellular localization of activin signaling components in testes of the wild ground squirrel during the breeding and nonbreeding seasons. The immunolocalizations of ActRIIB (activin type II receptor B) and activin-related SMADs (phospho-SMAD2/3, SMAD4 and SMAD7) were observed by immunohistochemistry. Total proteins were extracted from testicular tissues in the breeding and nonbreeding seasons and were used for Western blotting analysis for ActRIIB and SMADs. Immunoreactivities of activin signaling components were greater in the testes of the breeding season, and then decreased to a relatively low level in the nonbreeding season. ActRIIB and related SMADs were widely spread in the active testes, while spermatogonia were the predominant cellular sites of activin signal transduction during arrested spermatogenesis. The dynamic regulation of activin type II receptor and SMADs indicated that the activin signal pathway played an important paracrine role in seasonal spermatogenesis of the wild ground squirrel. Furthermore, the distinct localizations and immunoreactivity of ActRIIB and SMADs might suggest different functions of activin in seasonal spermatogenesis.  相似文献   

3种中药提取物对皮肤癣菌的体外联合药敏试验     

陈章宝  周泽扬  吴长龙  徐娇  石东霞 《中国兽医杂志》2012,48(4):75-77

研究苦参、白鲜皮和土荆皮提取物在石膏样小孢子菌、犬小孢子菌、须癣毛癣菌3株皮肤癣菌体外联合药敏试验中的相互作用,为临床用药提供参考依据。采用棋盘微量稀释法测量3种中药提取物对皮肤癣菌的联合抑菌指数(fractional in-hibitory concentration index,FICI)对其联用效果进行评价。结果发现,苦参醇提物与白鲜皮醇提物两者联合应用,对3株皮肤癣菌FICI值分别为1,0.75,1,FICI值均≤1,对3株真菌的抑制效果呈相加作用;土荆皮醇提物与苦参醇提物、白鲜皮醇提物联合应用,FICI值均≥2,对3株真菌的抑制效果呈无关或拮抗作用。  相似文献   

LTR对J亚群禽白血病病毒感染的影响     

冯少珍  李娇  吴晓婵  曹伟胜  廖明 《中国兽医杂志》2012,48(3):3-6

为探讨LTR基因在骨髓瘤病变型J亚群禽白血病病毒(ALV-J) NX0101致病中的作用,利用反向遗传将血管瘤病变型ALV-J HN06株中两端LTR元件替换至NX0101株的相应位置,拯救出重组病毒NX-HNLTR株.人工接种7日龄SPF雏鸡,分别检测NX0101株和NX-HNLTR株对鸡体的影响.感染鸡生长都较慢.感染NX0101株的鸡,胸腺指数和腔上囊指数明显比对照组低,脾脏指数与对照组相比波动较大,骨髓和脾脏在攻毒后3周可检测到病毒整合到基因组中,胸腺和腔上囊在攻毒后6周才检测到.感染NX-HNLTR株的鸡脾脏指数明显比对照组低,攻毒后2周可检测到病毒整合到脾脏基因组中,骨髓和胸腺分别在攻毒后3周和6周检测到.结果提示,LTR对NX0101株感染鸡的免疫器官有一定的影响.  相似文献   

靶向env及LTR基因的siRNA抑制ALV-J 复制的研究     

李娇  冯少珍  黄武  吴晓婵  李育豪  曹伟胜  廖明 《中国畜牧兽医》2012,39(8):16-19

试验针对J亚群禽白血病病毒的env及LTR基因,根据它们的保守序列,分别设计合成了4~5对siRNA,并将其克隆至pSilencer 4.1,构建siRNA重组表达质粒。将该质粒转染DF-1细胞6 h后以10³ TCID₅₀接种ALV-J,利用Real-time RT-PCR在mRNA表达水平检测各重组质粒对病毒复制的影响。结果表明,与阴性对照相比,pSi4.1-env各重组质粒对env基因的抑制效果达到18.15%~63.43%,pSi4.1-LTR各重组质粒的抑制效果则达到19.37%~45.41%。  相似文献