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1.
Frequent periods of drought conditions are known to limit plant performance,primary production,and ecosystem stability in arid and semi-arid desert steppe environments.Plants often avoid competition by shifting their water use seasonally,which affects the water-use patterns of dominant species as well as the composition and structure of plant communities.However,the water-use strategies of dominant herbaceous species,which grow under natural field conditions in the desert steppe region of Ningxia Hui Autonomous Region,China,are poorly known.Here,we explored the possible sources of water uptake and water-use efficiency(WUE)of three dominant herbaceous plant species(Stipa breviflora,Agropyron mongolicum,and Glycyrrhiza uralensis)in a native desert steppe in the semi-arid area of Ningxia through an analysis of multiple parameters,including(1)the stable isotopic oxygen and hydrogen(δ18O andδ2H)compositions of precipitation,soil water,and stem water,(2)the carbon isotope(13C)composition of leaves,and(3)the soil water contents,based on field sampling across varying water conditions from June to September,2017.Frequent small precipitation events replenished shallow soil water,whereas large events only percolated down to the deep soil layers.Changes in soil water availability affected the water-use patterns of plants.Generally,during light precipitation periods,the deep root system of G.uralensis accessed deeper(>80 cm)soil water,whereas S.breviflora and A.mongolicum,which only have shallow roots,primarily absorbed water from the shallow and middle soil layers.As precipitation increased,all three plant species primarily obtained water from the shallow soil layers.Variation in soil water uptake between the dry and wet seasons enabled plants to make better use of existing satoil water.In addition,theδ13C values of G.uralensis and S.breviflora were higher than those of A.mongolicum.Theδ13C values of the three plant species were significantly negatively correlated with soil water content.Therefore,G.uralensis and S.breviflora maintained a higher WUE through their conservative and water-saving strategies across the entire growing season.In contrast,A.mongolicum,with a relatively low WUE in the wet season but a high WUE in the dry season,exhibited a more flexible water-use strategy.The different water-use strategies of these dominant plant species demonstrated the mechanisms by which plant communities can respond to drought. 相似文献
2.
Water is a limiting factor in the restoration and construction of desert steppe. Exploring plant water sources is necessary to understand soil-plant interactions and species coexistence; however, water sources of major plant communities within the desert steppe of Ningxia Hui Autonomous Region, China remain poorly understood. In this study, we analyzed the water uptake of plants in four typical communities: Agropyron mongolicum Keng.; Sophora alopecuroids Linn.; Stipa breviflora Griseb., and Achnatherum splendens (Trin.) Nevski communities. Stable isotopes δD and δ18O in the xylem of plant and soil water at different soil depths were analyzed. An IsoSource model was used to determine the soil depths from which plants obtained water. Results showed that A. mongolicum community obtained water predominantly from 0-20 and 40-80 cm depth, S. alopecuroids community from 0-20 cm depth, S. breviflora community from 0-40 cm depth, and A. splendens community from 0-20 and 80-140 cm depths. S. alopecuroides had a wider range of soil depths for water extraction, i.e., utilizing different water sources depending on habitat, and the plasticity of its water uptake pattern determined its role in different communities. Water source of plants relayed heavily on the distribution of their roots. Competition for soil water exists between different plant life forms in the sierozem habitat (A. mongolicum, S. alopecuroids, and S. breviflora communities), and in the sandy soil habitat (A. splendens community). The use of soil water by A. splendens community is more spatially differentiated, and shrubs and herbs can coexist stably. Under the pattern of extended drought period in the future, sierozem habitat may be more favorable for the formation of a dominant monoculture community type of perennial fibrous plants. In aeolian sandy soil habitat, A. splendens had a strong competitive advantage, and the growth of shallow-rooted plants was easily suppressed. 相似文献
3.
Keiichi KIMURA 《干旱区科学》2022,14(8):867-876
Shrub species are used in restoration projects on dryland for their facilitation effects, which include environmental improvements and protection from herbivore feeding. Facilitation effects on forage grasses are potentially important in improving grazing capacity on rangelands. However, the morphology-dependent performance of benefactor plants in facilitating forage species growth and supplementation under moderate grazing intensity remains unclear. Here, our main purpose was to measure facilitation performance in terms of the survival of a native forage grass, Agropyron cristatum (L.) Gaertn. (Gramineae)., in accordance with the growth conditions of a sand-fixing benefactor shrub, Caragana microphylla Lam., in the Hulun Buir Grassland, northern China. Six study sites with patches of A. cristatum and C. microphylla were established at the foot of fixed sand dunes. At each site, five quadrats were set in places where C. microphylla coverage was 100% and A. cristatum grew among the shrubs (shrub quadrats), and another five were set where A. cristatum grew alone without C. microphylla (grass quadrats). We measured the morphological traits of C. microphylla and A. cristatum in all 60 quadrats, along with the soil water content and soil temperature. The data were compared between the shrub and grass quadrats by generalized linear mixed-effect models to assess the shrub's facilitation effects. We also used such models to elucidate the relationship between the average height of C. microphylla and the morphological traits of A. cristatum in the shrub quadrats. The maximum height, average grazed height, and the number of seed heads of A. cristatum were greater in the shrub quadrats than in the grass quadrats. The soil surface temperature was lower in the shrub quadrats. The maximum height and seed head number of A. cristatum were positively associated with the average height of C. microphylla. These results suggest that the grazing impact and heat stress were smaller in shrub quadrats than in grass quadrats, and that the degree of this protective effect depended on the shrub height. The shrub canopy seemed to reduce the increase in soil temperature and keep the grass vigorous. Livestock likely avoided grazing grasses in the C. microphylla patches because of the shrub's spiny leaves; only the upper parts of the grass stems (including the seed heads) protruding from the shrub canopy were grazed. The sand-fixing shrub thus moderates the grazing impact and soil temperature, and contributes to vegetation restoration and grazing system sustainability. 相似文献
4.
阐明斑块尺度上物种共存格局，对于深入认识荒漠草原破碎化草地生物多样性的维持机理具有重要意义。按斑块的土壤生境退化程度，选取短花针茅荒漠草原3类典型群落斑块为研究对象，对比分析不同斑块的物种构成、多样性及物种间的共存关系格局。结果表明：① 斑块A属单优种短花针茅（Stipa breviflora）群落；斑块B为短花针茅+草木樨状黄耆（Astragalus melilotoides）群落；斑块C为苦豆子（Sophora alopecuroides）+老瓜头（Cynanchum komarovii）+猪毛蒿（Artemisia scoparia）群落。② 群落结构中斑块A和斑块B多样性相近，均高于无短花针茅生长的斑块C。③ 基于零模型的分析结果显示，物种共存格局的复杂性和强度为：斑块A>斑块B>斑块C，且下降趋势明显，斑块A存在的16组显著物种对中有4组为显著竞争关系，而斑块C中的物种对减少到7组，且仅存在猪毛蒿与苦豆子组显著竞争物种对。结论：表明未沙化的土壤生境斑块是荒漠草原破碎化草地生物多样性维持的一个重要前提，土壤生境的退化显著降低了斑块内部群落组织的复杂性和物种间相互作用的强度，不利于群落的自我维持。 相似文献
5.
Snow resisting capacity of vegetation is important for secondary distribution of water resources in seasonal snow areas of grassland because it affects the regeneration,growth and nutrient circulation of vegetation in grassland.This study investigated vegetation characteristics(canopy height,canopy length and crown width)of Caragana microphylla Lam.(shrub)and Achnatherum splendens(Trin.)Nevski.(herb),and snow morphologies(snow depth,snow width and snow braid length)in a typical steppe region of Inner Mongolia,China in 2017.And the influence of vegetation characteristic on snow resisting capacity(the indices of bottom area of snow and snow volume reflect snow resisting capacity)was analyzed.The results showed that snow morphology depends on vegetation characteristics of shrub and herb.The canopy height was found to have the greatest influence on snow depth and the crown width had the greatest influence on snow width.The canopy length was found to have little influence on morphological parameters of snow.When the windward areas of C.microphylla and A.splendens were within the ranges of 0.0-0.5 m2 and 0.0-8.0 m2,respectively,the variation of snow cover was large;however,beyond these areas,the variation of snow cover became gradually stable.The potential area of snow retardation for a single plant was 1.5-2.5 m2 and the amount of snow resistance was 0.15-0.20 m3.The bottom area of snow and snow volume(i.e.,snow resisting capacity)of clumped C.microphylla and A.splendens was found to be 4 and 25 times that of individual plant,respectively.The results could provide a theoretical basis both for the estimation of snow cover and the establishment of a plant-based technical system for the control of windblown snow in the typical steppe region of Inner Mongolia. 相似文献
6.
Caragana korshinskii Kom. and Tamarix ramosissima Ledeb. are pioneer shrubs for water and soil conservation, and for windbreak and sand fixation in arid and semi-arid areas. Understanding the water use characteristics of different pioneer shrubs at different ages is of great importance for their survival when extreme rainfall occurs. In recent years, the stable isotope tracing technique has been used in exploring the water use strategies of plants. However, the widespread δ2H offsets of stem water from its potential sources result in conflicting interpretations of water utilization of plants in arid and semi-arid areas. In this study, we used three sets of hydrogen and oxygen stable isotope data (δ2H and δ18O, corrected δ2H_c1 based on SW-excess and δ18O, and corrected δ2H_c2 based on -8.1‰ and δ18O) as inputs for the MixSIAR model to explore the water use characteristics of C. korshinskii and T. ramosissima at different ages and in response to rainfall. The results showed that δ2H_c1 and δ18O have the best performance, and the contribution rate of deep soil water was underestimated because of δ2H offset. During the dry periods, C. korshinskii and T. ramosissima at different ages both obtained mostly water from deeper soil layers. After rainfall, the proportions of surface (0-10 cm) and shallow (10-40 cm) soil water for C. korshinskii and T. ramosissima at different ages both increased. Nevertheless, there were different response mechanisms of these two plants for rainfall. In addition, C. korshinskii absorbed various potential water sources, while T. ramosissima only used deep water. These flexible water use characteristics of C. korshinskii and T. ramosissima might facilitate the coexistence of plants once extreme rainfall occurs. Thus, reasonable allocation of different plants may be a good vegetation restoration program in western Chinese Loess Plateau. 相似文献
7.
通过对青海省治沙试验站3 a、5 a、10 a、16 a和30 a生的中间锦鸡儿（Caragana intermedia Kuang et H. C. Fu）人工林细根生物量的测定分析，了解其细根生物量的垂直分布和动态变化特征以及周转速率。结果表明：① 中间锦鸡儿人工林约41％的活细根和39％的死细根分布在0～20 cm 的土层，38％的活细根和死细根分布在20～40 cm 的土层，21％的活细根和23％的死细根分布在40～60 cm 的土层。② 细根生物量表现出明显的季节动态性，活细根生物量峰值出现在6月和8月或者6月和9月，8月或9月达到最大值；死细根生物量峰值出现8月和9月，也是8月或9月达到最大值。③ 不同林龄人工林细根周转速率分别为：0.53、0.66、0.56、0.73、0.78次﹒a-1。细根生物量和周转率均随林龄增大而增加，随土层加深而减小。 相似文献
8.
为了探究猪毛蒿Artemisia scoparia精油及其活性成分萜品—4—醇对黄曲霉Aspergillus flavus的抗菌活性及其在花生贮藏保鲜中的应用前景，通过气相色谱—质谱联用（Gas Chromatography—Mass Spectrometer， GC—MS）技术对猪毛蒿精油进行成分分析；采取熏蒸法检测猪毛蒿精油及萜品—4—醇对黄曲霉菌丝生长，孢子萌发和花生体内霉菌数的影响；通过扫描电镜观察猪毛蒿精油和萜品—4—醇对黄曲霉显微结构的影响。结果显示猪毛蒿精油由24种化合物组成，其主要成分为桉叶油醇（43.8%），萜品—4—醇在猪毛蒿精油中的含量为2.81%；猪毛蒿精油和萜品—4—醇可显著抑制黄曲霉菌丝的生长，并导致菌丝皱缩、扭曲和凹陷；体内抑菌试验发现，猪毛蒿精油和萜品—4—醇能显著降低花生体内霉菌数。 相似文献
9.
为了解绒柏Chamaecyparis pisifera精油和日本扁柏Chamaecyparis obtuse精油对蚊虫的生物活性,通过浸渍法测试了两种植物精油对白纹伊蚊Aedes albopictus和致倦库蚊Culex pipiens quinquefasciatus 4龄幼虫及蛹的毒杀活性,采用人体局部涂肤法测试其对白纹伊蚊成蚊的驱避活性,并利用气相色谱-质谱联用仪（GC-MS）定性分析了精油的化学成分。结果表明,绒柏精油和日本扁柏精油对白纹伊蚊4龄幼虫/蛹的24 h LC50分别为47.66/152.33和73.11/205.06 μg/mL,对致倦库蚊4龄幼虫/蛹的24 h LC50分别为31.74/107.61和63.94/131.42 μg/mL。以1.5和2.0 μL/cm2剂量涂抹人体皮肤,绒柏精油、日本扁柏精油驱避白纹伊蚊的完全保护时间分别是3.24 h和0.78 h、5.45 h和1.86 h。经GC-MS分析鉴定出绒柏精油中含α-蒎烯（29.89%）、17-norkaur-15-ene（9.96%）、Δ-3-蒈烯（9.79%）等16种成分,日本扁柏精油含Δ-3-蒈烯（35.33%）、α-蒎烯（25.60%）、β-月桂烯（12.86%）等22种成分。可见,绒柏精油和日本扁柏精油对白纹伊蚊和致倦库蚊4龄幼虫及蛹有较强的毒杀活性,而且绒柏精油对白纹伊蚊还有很强的驱避活性,具有研发为环保型蚊虫防控剂的潜力。 相似文献
10.
Jinhu ZHANG 《干旱区科学》2018,10(6):821-832
The complex interactions in desert ecosystems between functional types and environmental conditions could be reflected by plant water use patterns. However, the mechanisms underlying the water use patterns as well as the water sources of Tamarix laxa in the mega-dunes of the Badain Jaran Desert, China, remain unclear. This study investigated the water sources and water use patterns of T. laxa using the stable oxygen isotope method. The δ18O values of xylem water, soil water in different layers (0-200 cm), rainwater, snow water, lake water, atmospheric water vapor, condensate water, and groundwater were measured. The sources of water used by T. laxa were determined using the IsoSource model. The results indicate that T. laxa mainly relies on soil water. At the beginning of the growing season (in May), the species is primarily dependent on water from the middle soil layer (60-120 cm) and deep soil layer (120-200 cm). However, it mainly absorbs water from the shallow soil layer (0-60 cm) as the rainy season commences. In September, water use of T. laxa reverts to the deep soil layer (120-200 cm). The water use patterns of T. laxa are closely linked with heavy precipitation events and soil water content. These findings reveal the drought resistance mechanisms of T. laxa and are of significance for screening species for ecological restoration. 相似文献
11.
WANG Chunyuan 《干旱区科学》2021,13(7):744-758
Drought is one of the most significant natural disasters in the arid and semi-arid areas of China. Populations or plant organs often differ in their responses to drought and other adversities at different growth stages. At present, little is known about the size- and leaf age-dependent differences in the mechanisms of shrub-related drought resistance in the deserts of China. Here, we evaluated the photosynthetic and physiological responses of Artemisia ordosica Krasch. to drought stress using a field experiment in Mu Us Sandy Land, Ningxia Hui Autonomous Region, China in 2018. Rainfall was manipulated by installing outdoor shelters, with four rainfall treatments applied to 12 plots (5 m×5 m). There were four rainfall levels, including a control and rainfall reductions of 30%, 50% and 70%, each with three replications. Taking individual crown size as the dividing basis, we measured the responses of A. ordosica photosynthetic and physiological responses to drought at different growth stages, i.e., large-sized (>0.5 m2) and small-sized (≤0.5 m2) plants. The leaves of A. ordosica were divided into old leaves and young leaves for separate measurement. Results showed that: (1) under drought stress, the transfer efficiency of light energy captured by antenna pigments to the photosystem II (PSII) reaction center decreased, and the heat dissipation capacity increased simultaneously. To resist the photosynthetic system damage caused by drought, A. ordosica enhanced its free radical scavenging capacity by activating its antioxidant enzyme system; and (2) growth stage and leaf age had effects on the reaction of the photosynthetic system to drought. Small A. ordosica plants could not withstand severe drought stress (70% rainfall reduction), whereas large A. ordosica individuals could absorb deep soil water to ensure their survival in severe drought stressed condition. Under 30% and 50% rainfall reduction conditions, young leaves had a greater ability to resist drought than old leaves, whereas the latter were more resistant to severe drought stress. The response of A. ordosica photosynthetic system reflected the trade-off at different growth stages and leaf ages of photosynthetic production under different degrees of drought. This study provides a more comprehensive and systematic perspective for understanding the drought resistance mechanisms of desert plants. 相似文献
12.
为发掘具有防治茶园杂草潜力的生防菌，本研究从江苏、浙江和安徽3省共16个茶园采集感病杂草，采用组织分离法分离出病原菌，通过菌饼回接验证获得了44株具有致病力的植物病原菌，从中筛选出了10株致病性较强的优势菌株。利用柯赫氏法则验证优势菌株后，通过观察优势病原菌的形态特征，结合rDNA—ITS基因片段序列分析，确定10株优势菌株分别为平脐蠕孢属的狗尾草平脐蠕孢Bipolaris setariae、链格孢属的链格孢霉Alternaria alternata、弯孢属的间型弯孢Curvularia intermedia和新月弯孢Curvularia lunata、镰刀属的再育镰刀菌Fusarium proliferatum和木贼镰刀菌Fusarium equiseti、棒孢属的多主棒孢Corynespora cassiicola和茎点霉属的荸荠茎点霉Didymella bellidis，共6属8种的病原真菌。结合作物安全性问题，木贼镰刀菌、再育镰刀菌、狗尾草平脐蠕孢、间型弯孢和新月弯孢5种病原菌被认为具有开发成防除茶园杂草生物除草剂的较好潜力。 相似文献
13.
本文以超低量喷雾的方式探究了在环境湿度调控下,球孢白僵菌Beauveria bassiana Bb202和玫烟色虫草Cordyceps(=Isaria)fumosorosea Ifu13a在不同应用剂量下对棉蚜Aphis gossypii的田间防效.结果表明,提高环境湿度可明显提高两种昆虫病原真菌对棉蚜的防效.在田间防... 相似文献
14.
为比较黏虫幼虫、米蛾幼虫、柞蚕蛹3种替代猎物对于饲喂蠋蝽的营养适合性,在室内测定了3种猎物的营养组成以及蠋蝽取食3种猎物后的发育历期、体重、体长、繁殖力等生物学参数,为扩繁蠋蝽提供依据。结果表明,蠋蝽取食3种猎物均能正常完成世代发育。体重、体长、性比不受食物处理的影响。蠋蝽在取食黏虫和柞蚕蛹时,其发育历期、存活率、产卵量、卵孵化率等指标无显著差异。蠋蝽取食米蛾时,卵孵化至成虫的发育历期为29.88 d,明显长于取食黏虫和柞蚕蛹的蠋蝽,历期分别为25.57和26.15 d;世代单雌平均产卵量为231.44粒,显著低于取食黏虫与柞蚕的360.00和441.00粒;成虫获得率为23.78%,极显著低于取食黏虫与柞蚕的获得率60.00%和60.56%;然而雌、雄虫寿命均较取食黏虫与柞蚕有所延长。综上所述,黏虫幼虫可作为室内扩繁蠋蝽的猎物。 相似文献
15.
为明确宁夏四类主要草原的蝗虫物种组成、多样性和对天敌、植被、土壤及其气候等生物和非生物因子的响应,2019-2020年在宁夏温性草甸草原、温性草原、温性荒漠草原和温性草原化荒漠四类草原对蝗虫及天敌物种进行了调查采集,通过物种数、个体数、多样性指数、优势度指数、丰富度指数及均匀性指数分析蝗虫、天敌和昆虫的多样性,并就草原蝗虫优势种和多样性对天敌、植被、土壤及气候等生物和非生物因子的响应进行分析。结果表明,共采集鉴定草原蝗虫和天敌个体数分别有743头和3592头,物种数分别有27种和24种;温性草原上发生的蝗虫和天敌物种和数量均最多,蝗虫和天敌的物种分别为23种和21种,数量分别为432头和1682头;温性草原化荒漠上发生的蝗虫和天敌物种和数量均最少,蝗虫和天敌的物种分别为8种和7种,数量分别为34头和132头。蝗虫优势种有白纹雏蝗Chorthippus albonemus、短星翅蝗Calliptamus abbreviatus和亚洲小车蝗Oedaleus asiaticus三种,天敌优势种有直角通缘步甲Pterostichus gebleri、麻步甲Carabus brandti和短翅伪葬步甲Pseudotaphoxenus brevipennis三种。温性草原无论是在草原蝗虫群落中,还是整个昆虫和天敌群落中,其丰富度指数均显著高于其他三类草原;草原蝗虫多样性指数和丰富度指数与天敌多样性指数和丰富度指数间均存在极显著正相关关系,与天敌优势度指数间存在极显著负相关关系;短星翅蝗和亚洲小车蝗发生均与天敌直角通缘步甲呈显著正相关关系,白纹雏蝗与禾本科植被盖度、高度、生物量,菊科植被盖度、生物量、频度、高度、土壤饱和持水量、毛管持水量、田间持水量、毛管孔隙度、总孔隙度、有机质、碱解氮、海拔和降水量间均呈显著正相关关系,与土壤容重、pH、平均气温和最高气温间均呈极显著负相关关系。 相似文献
16.
Species composition, distribution patterns and ecological functions of biological soil crusts in the Gurbantunggut Desert 总被引：1，自引：0，他引：1
As one of the most important biological factors that maintain the stability of the largest fixed and semi-fixed desert in China,the Gurbantunggut Desert,the biological soil crusts (BSCs) develop well and play critical ecological roles in the desert ecosystem. In this paper,we briefly summarize our research findings since 2002 including species composition,distribution pattern and ecological functions of BSCs in the desert. Our results indicate abundant species diversity of BSCs in the Gurbantunggut Desert in comparison to other deserts in China. At the scales of sand dune or whole desert,the distribution patterns of BSCs are location-specific. The existence of BSCs in this desert could:(1) accelerate the formation of desert soil and the weathering of minerals; (2) accumulate organic matter in surface soil through related species in soil crusts; (3) enhance the abilities of sand surface to resist wind erosion; (4) influence seed germination of vascular plants; and (5) enhance the production of dew deposition on sandy soil surface. 相似文献
17.
灌木的生态特性与生态效能的研究与进展 总被引：14，自引：2，他引：14
文章论述了国内外在灌木的生态性和生态效能方面的研究概况,介绍了灌木的主要特征及其对生长环境和干扰响应的生态学论述,并分别就干旱荒漠区灌木、草牧场地灌木、盐碱地灌木和森林区次生灌木四种主要灌木类型进行了说明。另外主要从生物多样性、水土保持、防风固沙、土壤改良、改善气候等五个方面阐述了灌木林的生态效能研究现状。最后指出灌木今后的重点研究方向。 相似文献
18.
Maryam MOSLEHI JOUYBARI 《干旱区科学》2022,14(10):1099-1108
Biological invasions can alter soil properties within the range of their introduced, leading to impacts on ecosystem services, ecosystem functions, and biodiversity. To better understand the impacts of biological invasions on soil, we compared topsoil physiochemical properties at sites with invasive alien tree species (Prosopis juliflora), native tree species (Prosopis cineraria, Acacia tortilis, and Acacia ehrenbergiana), and mixed tree species in Hormozgan Province of Iran in May 2018. In this study, we collected 40 soil samples at a depth of 10 cm under single tree species, including P. juliflora, P. cineraria, A. tortilis, and A. ehrenbergiana, as well as under mixed tree species. The results showed that organic matter, moisture, potassium, calcium, nitrogen, and magnesium in topsoil at sites with A. tortilis and A. ehrenbergiana growing in combination with P. cineraria were higher than that at sites where P. juliflora was present (P<0.05). Sodium at sites with A. tortilis and A. ehrenbergiana growing in combination with P. cineraria and P. juliflora was lower as compared to that at sites with just A. tortilis and A. ehrenbergiana. Electrical conductivity was lower at sites with A. tortilis and A. ehrenbergiana growing in combination with P. cineraria, and it was higher at sites with mixed Acacia and P. juliflora trees. Based on the generally more positive effect of native Acacia and P. cineraria on topsoil physiochemical properties as compared to the P. julifora, afforestation with native tree species is preferable for soil restoration. In addition, due to the negative effects of P. julifora on soil properties, P. julifora spread should be better managed. 相似文献
19.
本试验以转Bt+CpTI基因抗虫棉花SGK321与其亲本石远321为研究对象,研究普通草蛉幼虫捕食2种棉花上棉蚜的捕食功能反应和搜寻效应,旨在评价转Bt+CpTI基因棉花对普通草蛉幼虫捕食功能的影响,为转Bt基因棉花对非靶标昆虫的评价研究提供参考。结果表明,普通草蛉幼虫随龄期的增长对棉蚜的瞬时攻击率加快,普通草蛉1龄幼虫取食SGK321和石远321棉花上棉蚜的瞬时攻击率为0.045和0.044,至3龄时瞬时攻击率可达0.107和0.093,但处理和对照间差异并未达显著水平;普通草蛉幼虫对SGK321和石远321棉花上棉蚜的取食时间分别从1龄的0.984和0.992 h减少到3龄的0.130和0.125 h,但普通草蛉对2种棉花上棉蚜的处理时间差异并未达显著水平。当N0→∞时,取食2种棉花上棉蚜的普通草蛉幼虫日最大捕食量之间亦不存在显著差异。随着棉蚜密度的增加,普通草蛉各龄幼虫对2种棉花上棉蚜的搜寻效应均呈下降趋势,即1龄幼虫由0.0239和0.0235降为0.015和0.0148;2龄幼虫由0.0479和0.0464降为0.0245和0.0242;3龄幼虫由0.0631和0.0588降为0.0207和0.0207。研究表明转Bt+CpTI基因棉花对普通草蛉幼虫捕食棉蚜的功能反应和搜寻效应没有显著的影响。 相似文献
20.
2013年9月初的调查发现,棉大卷叶螟幼虫在锦葵科的蜀葵、黄秋葵和陆地棉上的种群数量具有显著差异。2014年,对锦葵科4种植物上棉大卷叶螟幼虫的种群消长动态进行了系统的调查研究。结果表明,苘麻、蜀葵和黄秋葵上棉大卷叶螟幼虫的种群密度显著高于陆地棉上,上述4种锦葵科植物上棉大卷叶螟幼虫的种群密度依次为（6.26·1.16）、（7.95·0.52）、（5.42·0.54）和（0.10·0.10）头/m2。说明锦葵科的苘麻、蜀葵和黄秋葵是棉大卷叶螟幼虫的喜食寄主植物,有望开发成为棉田棉大卷叶螟成虫的诱集植物。 相似文献