去劣疏伐对油松种子园交配系统及遗传多样性影响的研究

 为了解去劣疏伐对种子园群体交配系统和遗传组成的影响程度,采用水平淀粉凝胶电泳方法,对10个等位酶位点上,分别用混合交配模型(MLT)和Biosys-Ⅰ程序,分析了去劣疏伐前后辽宁兴城油松种子园3个年份群体的交配系统和遗传多样性变化。种子园去劣疏伐前(1993年)种子试样多位点异交率为0.962,而疏伐后2个年份(1996年和2000年)试样的多位点异交率明显减小,分别为0.795和0.801。疏伐后种子园的自交率有升高的趋势,从疏伐前的0.038到疏伐后的0.205和0.199。近交系数也有明显变化,疏伐前为0.141,疏伐后分别为0.341和0.239。去劣疏伐后种子园的每个位点的平均等位基因数(A)和多态位点百分率(P)都有不同程度的降低。本文对影响种子园交配系统和遗传多样性的因素作了探讨。     

向家坝水电站工程扰动区不同类型边坡土壤酸碱度与肥力分析

对向家坝水电站工程扰动区7种不同类型边坡土壤的酸碱度（pH)进行检测,并运用标准综合级别法对其肥力状况进行分析.结果表明：在向家坝水电站工程扰动区,植被混凝土边坡土壤呈微碱性,其他边坡土壤均呈不同程度的酸性,土壤pH值依次为:植被混凝土(7.68±0.04)>弃渣地(6.96±0.02)>框格梁覆土(6.93±0.16)>客土喷播(6.75±0.35)>厚层基材(6.67±0.36)>天然次生林(5.68±1.25)>天然林(4.71±0.23);不同类型边坡土壤肥力的综合级别值大小为: 植被混凝土(3.06±0.02）<厚层基材(4.06±0.78)<天然林(4.20±0.10)<天然次生林(4.32±0.16)<框格梁覆土(4.62±0.06)< 客土喷播(4.90±0.01)<弃渣地(5.00±0.10),植被混凝土肥力状况最佳,弃渣地肥力状况最差.采用人工修复技术添加的水泥、复合肥及腐殖质在调节边坡土壤pH值和维持其肥力方面起到一定的作用,可为植被生长提供良好的土壤条件.     

松嫩平原不同盐渍土条件下蓝藻群落的生态分布

以松嫩平原典型的不同程度盐碱化草地为研究对象,测定了其土壤的电导率、离子组成、有机碳等,分析了3种类型盐碱土上的固氮蓝藻群落.结果表明:3种类型土壤的理化特征和蓝藻群落各有其特点,固氮蓝藻有7个属,其中以丝状种类占优势;蓝藻在不同类型盐碱土上分布略有差异,在中度盐碱土种类最为丰富;不同种类的蓝藻对生境的选择性不同;松嫩平原草地是个脆弱的生态系统,其土壤理化特性及藻类分布较特殊.因此,必须加强保护和管理.     

桃园生草对土壤有机碳及活性碳库组分的影响

果园生草是解决传统清耕引起的水土流失、土壤有机质减少、土壤肥力下降和果品品质变劣的果园地面管理措施之一。阐明不同牧草种类对土壤有机碳及其活性组分的影响是实现果园土壤生态管理、促进有机果品生产技术体系完善和果园土壤质量提高过程中亟待解决的问题。通过研究桃园人工种植黑麦草和毛苕子对土壤总有机碳(TOC)及其活性组分(微生物量碳(MBC)、水溶性有机碳(WSOC)、轻组有机碳(LFOC)、重组有机碳(HFOC)以及团聚体有机碳)的影响,探明豆科牧草与禾本科牧草种植对桃园土壤有机碳及其组分的影响及其差异。结果表明:与清耕对照(CK)相比,种植黑麦草后土壤TOC、MBC和WSOC分别提高了5.13%、76.4%和18.1%,种植毛苕子土壤LFOC提高了11.3%,土壤HFOC降低了13.2%,但对土壤TOC、MBC和WSOC未产生显著影响。此外,黑麦草显著提高土壤较大粒级(74μm)团聚体有机碳含量,而毛苕子则显著降低土壤较小粒级(2000μm)团聚体有机碳含量。对提高TOC而言,在桃园种植禾本科牧草黑麦草优于豆科牧草毛苕子。土壤MBC、WSOC、LFOC以及HFOC可以作为指示桃园土壤质量提高与否、表征土壤有机碳变化的敏感指标。     

Impact of floor management practices on the growth of groundcover species and soil properties in an apple orchard in northern China

Tillage and groundcover are the two mainly used management practices in orchard. Only small portion of orchard has been treated with groundcover in China, which would restrict our understanding of the scientific management of apple orchard. This study aimed to investigate the impact of different groundcover treatments on the plant growth of groundcover species and soil properties in an apple orchard near Beijing, northern China. Six commonly used groundcover species were chosen to grow underground. Our results showed that groundcover species had significant greater maximum photosynthesis rate (P_max) than weeds in control plots. Meanwhile, groundcover treatments could largely improve the microclimate of orchard compared with tillage treatment. Among all the groundcover species, alfalfa was proven to be the most appropriate species grown underground in apple orchard for its high P_max and high above-ground biomass. Groundcover treatments had little impact on soil bulk density, soil porosity and surface soil organic carbon (SOC) content. However, significantly greater deep soil organic carbon contents were found in two grass species, and significantly higher soil available nitrogen (N) contents were found in two leguminous species respectively. Our results indicated that groundcover treatment would be a sustainable management practice for apple orchard in northern China.     

柑桔园土壤脲酶活性年周期变化及脲酶抑制剂氢醌的效应

本研究初步探明南亚热带赤红壤柑桔园土壤脲酶活性的年周期变化:冬季最低,春季升至高峰,夏季开始下降,直至秋季仍处于较低水平。室内模拟试验表明:氢醌对柑桔园土壤脲酶活性有明显抑制作用,其抑制率随浓度提高而增加,且随着培养时间的延长而逐渐下降;添加氢醌处理的尿素水解持续时间,比不加氢醌的延长约1倍。     

梨小食心虫性信息素田间应用技术研究

梨小食心虫Grapholitha molesta(Busck)是梨园、桃园重要的果树害虫。本文比较研究了梨小食心虫性信息素在梨园、桃园悬挂不同高度、设置不同密度对梨小食心虫雄性成虫诱捕效果的影响,结果表明:在梨树树冠范围内,梨小食心虫性信息素最佳设置高度为2 m;在桃树树冠范围内,梨小食心虫性信息素最佳设置高度为1.5 m;同时,田间诱捕效果与性信息素设置密度密切相关,梨园中,每0.067 hm2设置密度为6¹0个诱芯时,对梨小食心虫的诱捕效果影响不大,而桃园中每0.067 hm2设置8个诱芯时,有最好的诱集效果。本研究可为梨小食心虫性信息素田间应用提供指导。     

苏云金杆菌在华北果园土壤中消长动态的研究

本文报道了产生核黄素的苏云金杆菌CH菌株在果园土壤中的消长动态。研究结果表明 ,将CH菌株制剂喷洒于苹果园土壤表面后 1个月内 ,CH菌株的菌数基本上维持在喷洒后的 10 5/ g水平 ,其后菌数急剧减少 ,2个月后从 10 5/ g的水平减少到 10 4 / g的水平 ,并长时间维持 10 4 / g这一水平 ;CH菌株制剂喷洒于果园土壤后对土壤中固有的Bacillus属细菌数的消长没有明显的影响 ,Bacillus属细菌数长时间维持在 10 6～ 10 5/ g之间 ,处于一种相对稳定的状态 ;在土壤透水性和灌水条件良好的土壤条件下 ,喷洒于土壤表面的苏云金杆菌可缓慢向深处移动。     

阿拉尔地区邻作枣园、棉田棉盲蝽及其主要天敌消长规律及时间生态位分析

通过对邻作枣园、棉田及枣-棉交错带棉盲蝽及其天敌的消长规律和时间生态位进行研究,结果发现：在3个生境中棉盲蝽优势种为绿盲蝽,优势度均为0.95以上,天敌优势种类为草蛉、多异瓢虫、食蚜蝇、黑食蚜盲蝽。绿盲蝽在枣园、枣-棉交错带和棉田5月上旬出现,6月下旬-7月上旬、8月上旬出现高峰,第二个峰值远高于第一个,8-9月大量发生,枣-棉交错带发生量高于枣园、棉田,天敌8-9月种群数量也迅速上升。相关性分析结果表明,绿盲蝽6月在棉田发生量与在枣-棉交错带发生量显著相关,7月在枣园发生量与在枣-棉交错带发生量显著相关;绿盲蝽与天敌发生量的相关性在枣-棉交错带最大,其次为在棉田,最低为在枣园。生态位分析结果表明,绿盲蝽在枣-棉交错带、棉田对时间资源的利用长,在枣园较短;天敌与绿盲蝽在时间资源生态位上重叠程度高,在时间上有一定的同步性。本研究结果表明,枣-棉交错带为绿盲蝽在枣园、棉田发生、迁移扩散的库源,天敌对绿盲蝽具有一定的跟随现象。     

Selection of hibernation sites by Anthonomus pomorum: preferences and ecological consequences

The apple blossom weevil, Anthonomus pomorum (L.) (Coleoptera: Curculionidae), has a long period of aestivo-hibernation in the adult stage lasting from summer to early spring of the following year. Potential hibernation sites within an apple orchard consist of high-stem rough-bark trees or dwarf smooth-bark trees. Field release-recapture experiments in 2 consecutive years showed that 64 and 47% of the weevils remained in the vicinity of the release sites in an area of high-stem trees and dwarf trees, respectively. The dispersing weevils moved over an average distance of 5.5 m in the dwarf tree area, as compared to 3.8 m in the high-stem tree area. The prevalent direction of dispersal was along tree rows in both areas. Some weevils displayed, after release in mid-July, a directional dispersal to the adjacent forests. Others, released in the dwarf tree area, dispersed towards the area of high-stem rough-bark apple trees. Experiments simulating various hibernation sites demonstrated that the litter of dry leaves was the most preferred overwintering shelter, yielding a relatively high survival rate. Branches with rough bark ranked second, while branches with smooth bark, grass and pure soil were not favourable for overwintering. Flight tendency in newly emerged weevils of summer generation was significantly higher in June/July than in August/September. This corresponds to the dispersal behaviour in the field. The timing of spring colonisation of apple trees was similar for weevils overwintering within the orchard and for those from outside. These results suggest that modern, dwarf apple orchards offer unfavourable conditions for overwintering, but that the relatively small proportion of weevils which manage to reach the adjacent forests find optimal hibernation sites there.