Diorhabda rybakowi Weise is one of the dominant pests feeding on Nitraria spp., a pioneer plant used for windbreaking and sand fixation purposes, and poses a threat to local livestock and ecosystems. To clarify the key olfactory genes of D. rybakowi and provide a theoretical basis for attractant and repellent development, the optimal reference genes under two different conditions (tissue and sex) were identified, and the bioinformatics and characterization of the tissue expression profiles of two categories of soluble olfactory proteins (OBPs and CSPs) were investigated. The results showed that the best reference genes were RPL13a and RPS18 for comparison among tissues, and RPL19 and RPS18 for comparison between sexes. Strong expressions of DrybOBP3, DrybOBP6, DrybOBP7, DrybOBP10, DrybOBP11, DrybCSP2, and DrybCSP5 were found in antennae, the most important olfactory organ for D. rybakowi. These findings not only provide a basis for further in-depth research on the olfactory molecular mechanisms of host-specialized pests but also provide a theoretical basis for the future development of new chemical attractants or repellents using volatiles to control D. rybakowi.

Angaracris rhodopa (Fischer et Walheim), Calliptamus abbreviatus (Ikonnikov), Myrmeleotettix palpalis (Zubowsky), and Oedaleus decorus asiaticus (Bey-Bienko) are the main grasshoppers that harm the natural grassland in the Hexi Corridor in Gansu, northwest China. In this study, the MaxEnt model was employed to identify the key environmental factors affecting the distribution of the four grasshoppers’ habitats and to assess their distribution under current and future climate conditions. The aim was to provide a basis for grasshopper monitoring, prediction, and precise control. In this study, distribution of suitable habitats for A. rhodopa, C. abbreviates, M. palpalis, O. decorus asiaticus were predicted under current and future climatic scenarios using the Maxent model. The average AUC (area under the ROC curve) and TSS (true skill statistic) values of the four grasshoppers were greater than 0.9, and the simulation results were excellent and highly reliable. The mean annual precipitation was the main factor limiting the current range of suitable areas for these four species. Under the current climate, A. rhodopa, C. abbreviatus, and O. decorus asiaticus were mainly distributed in the central and eastern parts of the Hexi Corridor, and M. palpalis was distributed throughout the Hexi Corridor, with a suitable area of 1.29 × 104, 1.43 × 104, 1.44 × 104, and 2.12 × 104 km2, accounting for 13.7%, 15.2%, 15.3%, and 22.5% of the total area of the grasslands in the Hexi Corridor, respectively. The highly suitable areas of A. rhodopa, C. abbreviatus, and O. decorus asiaticus were mainly distributed in the eastern-central part of Zhangye City, the western part of Wuwei City, and the western and southern parts of Jinchang City, with areas of 0.20 × 104, 0.29 × 104, and 0.35 × 104 km2, accounting for 2.2%, 3%, and 3.7% of the grassland area, respectively. The high habitat of M. palpalis was mainly distributed in the southeast of Jiuquan City, the west, middle, and east of Zhangye City, the west of Wuwei City, and the west and south of Jinchang City, with an area of 0.32 × 104 km2, accounting for 3.4% of the grassland area. In the 2030s, the range of A. rhodopa, C. abbreviatus, and O. decorus asiaticus was predicted to increase; the range of M. palpalis will decrease. The results of this study could provide a theoretical basis for the precise monitoring and control of key areas of grasshoppers in the Hexi Corridor.

Oedaleus decorus asiaticus, Calliptamus abbreviatus, Angaracris rhodopa, and Myrmeleotettix palpalis are the main grasshoppers that harm the natural grassland in the Hexi Corridor. In this study, the MaxEnt model was employed to identify the key environmental factors affecting the distribution of the four grasshoppers habitats and to assess their distribution under current and future climate change conditions. The aim was to provide a basis for grasshopper monitoring, prediction, and precise control. In this study, 61 occurrences of O. decorus asiaticus, 68 occurrences of A. rhodopa, 58 occurrences of C. abbreviatus, and 92 occurrences of M. palpalis were recorded by GPS, and the distribution of suitable habitats for O. decorus asiaticus, C. abbreviatus, A. rhodopa, and M. palpalis were predicted under current and future climatic scenarios using a MaxEnt model. The average AUC and TSS values of the four grasshoppers were greater than 0.9, and the simulation results were excellent and highly reliable. The mean annual precipitation was the main factor limiting the current range of suitable areas for these four species. Under the current climate, O. asiaticus, C. abbreviatus, and A. rhodopa were mainly distributed in the central and eastern parts of the Hexi Corridor, and M. palpalis was distributed throughout the Hexi Corridor, with a potential distribution area of 1.44×104, 1.43×104, 1.29×104, and 2.12×104 km2, accounting for 15.3, 15.2, 13.7, and 22.5% of the total area of the grasslands in the Hexi Corridor, respectively. The highly suitable areas of O. asiaticus, C. abbreviatus, and A. rhodopa were mainly distributed in the east-central part of Zhangye City, the western part of Wuwei City, and the western and southern part of Jinchang City, with areas of 0.35×104, 0.29×104, and 0.20×104 km2, accounting for 3.7, 3, and 2.2% of the grassland area, respectively. The high habitat of M. palpalis was mainly distributed in the southeast of Jiuquan City, the west, middle, and east of Zhangye City, the west of Wuwei City, and the west and south of Jinchang City, with an area of 0.32×104 km2, accounting for 3.4% of the grassland area. In the 2030s, the range of O. asiaticus, C. abbreviatus, A. rhodopa, and M. palpalis was predicted to decrease.

The developmental duration and survival rate of egg, larva and pupa and adult longevity and fecundity of Diorhabda rybakowi were investigated under six constant temperatures（18, 21, 24, 27, 30, 33℃） in this study. The results showed that the developmental durations of egg and larva declined and the growth rate accelerated along with the increase of temperature. The threshold temperatures for development of egg, larva, pupa, pre-oviposition of adult and generation of D.rybakowi were（10.4±0.8）（12.2±0.7）（8.7±0.9）（16.4±0.8）℃ and（8.6±0.9）℃, respectively, and the effective accumulated temperatures were（97.9±4.8）（158.2±7.9）（212.1±11.5）（158.6±13.6） and（838.0±43.9） degree-days, respectively. The larval survival rate decreased at 18℃ and 33℃, and the adult emergence rate decreased significantly at 33℃, while the egg survival rate was higher than the larval survival rate. The optimum temperature（T）range for the growth, development and reproduction of D. rybakowi was 21℃＜T≤30℃.

为探明牛角花齿蓟马 Odontothrips loti 对寄主植物花及其挥发物的嗅觉行为反应,选取紫花苜蓿Medicago sativa、黄花草木樨Melilotus officinalis、红豆草Onobrychis viciaefolia和红三叶Trifolium pratense 4种豆科牧草,采用Y型嗅觉仪测定了蓟马对上述 4种寄主植物的行为选择趋性,并采用动态顶空吸附法采集植物挥发物,气相色谱-质谱联用仪(GC-MS)鉴定化合物组分及含量分析.结果表明,与空气对照比较,牛角花齿蓟马对紫花苜蓿表现显著偏好选择,选择反应率为 70.6%,对其他 3 种寄主的行为反应差异不显著.两项选择中,与红豆草、红三叶比较,牛角花齿蓟马显著趋向选择紫花苜蓿,选择反应率分别为 78.3%和 68.7%,其余各组合处理间均无显著差异.花释放的挥发物中,4种牧草共鉴定出 40种化合物,分别是烷烃 1种,醇类 9种,酮类 2种,醛类 5种,酯类 9种,萜烯类 13种,酚类 1种.因子分析显示,用主成分分析法提取的因子 1,2,3分别解释了总方差概率的 56.65%,24.47%和 15.63%,对 3个因子挥发物组分的贡献大小依次是紫花苜蓿、黄花草木樨、红豆草和红三叶.由此推测部分关键寄主挥发物苯甲醛、β-石竹烯、α-蒎烯、月桂烯、棕榈酸甲酯和百里酚等在牛角花齿蓟马与寄主化学通讯过程中发挥重要作用.研究结果为进一步开发植物源引诱剂进行牛角花齿蓟马的绿色防控提供了依据.

To clarify the diversity and temporal dynamics of darkling beetles in Minqin temperate desert grassland， this study systematically investigated the communities of different subtypes of darkling beetles in gravelly， sandy， and saline desert grasslands in Minqin County， Gansu Province， from April to October 2021 using the pitfall trapping method. In this survey， 8492 individuals of 10 species in 8 genera were captured. The dominant species in the desert steppe in general were Microdera elegans and Sternoplax setosa setosa， which accounted for 26.88% and 25.07%， respectively， of the total individuals， whereas Eumylada potanini was an endemic species in gravelly desert grassland. The number of darkling beetles of their respective species in the three subtypes of desert grasslands peaked in July and dropped to the lowest level in October. The community abundance and Shannon–Wiener diversity index of the darkling beetles were significantly higher than those in saline desert grassland （P ＜ 0.05）， and the community richness of darkling beetles was significantly higher than that of sandy desert grassland （P ＜ 0.05）. The diversity of the darkling beetles was closely correlated with environmental factors: the community abundance index was significantly negatively correlated with the height of the vegetation community， soil water content， and vegetation cover （P ＜ 0.05）. The abundance index of the darkling beetles was significantly positively correlated with the plant Shannon–Wiener diversity index and plant richness （P ＜ 0.05）. The vegetation composition of the desert grassland is simple; therefore， the community composition of the darkling beetles is also simple. The plant diversity index and plant richness are higher in gravelly desert grasslands than in saline desert grasslands and sandy desert grasslands， so the darkling beetles are the most abundant in gravelly desert grasslands.

为探究牛角花齿蓟马Odontothrips loti的产卵选择及寄主营养和次生代谢物质对其产卵行为的影响,本研究观测了牛角花齿蓟马在苜蓿Medicago sativa、草木樨 Melilotus officinalis、红豆草Onobrychis cyri和红三叶Trifolium pratense 4种豆科牧草叶片上的产卵量和卵孵化率,同时测定、分析了牧草主要营养和次生代谢物质含量与蓟马产卵选择的相关性.结果表明,无选择条件下,牛角花齿蓟马在苜蓿上产卵量最高,为59.1粒/复叶,其次是草木樨,15.7粒/复叶,在红豆草和红三叶上的产卵量仅为0.9粒/复叶和1.1粒/复叶.卵孵化率在苜蓿上最高,为85.05％,在草木樨和红豆草上分别为40.09％和39.18％,红三叶上最低,为5.48％.两两选择条件下,牛角花齿蓟马明显偏好在苜蓿叶片上产卵,在其他牧草叶片上不产卵或产卵量极低.相关性分析表明,牛角花齿蓟马的产卵量与寄主可溶性蛋白含量显著正相关(r=0.722,P=0.002),卵孵化率与可溶性蛋白(r=0.673,P=0.004)和淀粉(r=0.586,P=0.017)含量显著正相关.牛角花齿蓟马产卵量分别与寄主总酚(r=-0.771,P＜0.001)、简单酚(r=-0.724,P=0.002)、单宁(r=-0.755,P=0.001)和黄酮(r=-0.672,P=0.004)4 种次生代谢物质含量呈显著负相关性.说明寄主叶片的可溶性蛋白含量高有利于牛角花齿蓟马产卵,总酚、简单酚、单宁和黄酮含量高,对蓟马产卵具有抑制作用.

Soils contain a remarkable diversity of organisms that are important regulators of ecosystem functions. However, the knowledge of how the environment shapes biodiversity patterns below ground remains limited in alpine areas of the Tibetan Plateau. Here, we conducted a microhabitat scale study (400 m2 plot) integrating data on soil and plant community characteristics to explore the driving forces of functional diversity of soil microbial and macroinvertebrate communities under disturbance by plateau zokor (Eospalax baileyi), a subterranean rodent inhabiting the Tibetan Plateau. The results show that plateau zokor disturbance led to a decline in the below -ground biomass of grasses, whereupon the total belowground plant biomass and soil organic carbon decreased significantly. The functional diversity of soil microbial and macroinvertebrate communities was significantly increased under plateau zokor disturbance. Redundancy analysis indicated that soil moisture, temperature and compaction, in combination with plant species richness and belowground biomass of forb were the most important factors in driving soil microbial and macroinvertebrate functional diversity. Piecewise structural equation modeling (SEM) revealed that plateau zokor mound disturbance had positive effects on the functional diversity of soil microbial and macroinvertebrate communities by regulating soil physical properties (moisture, temperature, and compaction) and plant species richness within the habitat. Further, zokor disturbance affected the functional diversity of soil microbial and macroinvertebrate communities indirectly via regulating soil organic carbon. Our study provides evidence that the functional diversity of microbes is more driven by envi-ronmental changes than those of macroinvertebrates.

The multicolored Asian ladybird beetle Harmonia axyridis is an important predatory natural enemy in alfalfa fields in China.The pea aphid Acyrthosiphon pisum and the thrip Odontothrips loti are two serious piercing-sucking pests in alfalfa fields.In this study,predatory functional response and predation preference were measured to clarify the biological control potential of H.axyridis towards A.pisum and O.loti.Briefly,the2 nd —3 rd instar nymphs of A.pisum and adults of O.loti were provided as prey for 1 st —4 th instar larvae and the female adults of H.axyridis,respectively.The results showed that the predatory functional response of the larvae and female adults of H.axyridis feeding on both of two prey species fitted with the HollingⅡmodel.Feeding on A.pisum nymphs,the 4 th instar larvae of H.axyridis displayed the highest predation ability,followed by the female adults.Meanwhile,the predation ability of the 1 st ,2 nd ,and 3 rd instar larvae gradually decreased with the reduction of developmental stage.When feeding on O.loti adults,the female adults of H.axyridis exhibited the highest predation ability,followed by the 4 th instar larvae,while the 2 nd and 3 rd instar larvae showed relatively low predation ability.Feeding on A.pisum nymphs and O.loti adults,the searching efficiency of the 1 st —4 th instar larvae and female adults of H.axyridis decreased with increasing prey density.When H.axyridis 4 th instar larvae and female adults were fed A.pisum nymphs and O.loti adults at different ratios （40:80,60:60 and 80:40）,the 4 th instar larvae preferred A.pisum with a predation preference index （D）＞1,whereas the female adults showed no preference with a predation preference index （D）＜1.In conclusion,H.axyridis has great control ability against the2 nd —3 rd instar A.pisum nymphs and O.loti adults,and the 4 th instar larvae and female adults exhibit especially higher predation capability compared to the younger larvae.The 4 th instar larvae of H.axyridis prefer A.pisum nymphs when they coexisted with O.loti adults.

[目的]探索施钾对苜蓿根冠生长与苜蓿抗蓟马的影响.[方法]选用甘农3号紫花苜蓿(Medicago sativa Gannong No.3)(G3)和甘农9号紫花苜蓿(M.sativa Gannong No.9)(G9)为材料,以牛角花齿蓟马(Odontothrips loti)为研究对象,在网室盆栽条件下,设置0.4、0.6、0.8、1.2 g(K2O)/10 kg土4个钾处理,以不施钾为对照,评价了不同钾处理下苜蓿的受害程度,并测定了两个苜蓿品种的根冠植物学特性和生物量变化.[结果]施钾后,苜蓿的受害指数显著下降,苜蓿的叶面积增大、株高升高、分枝数和侧根数增多,茎粗、根颈直径和主根直径增粗,根、茎和叶的生物量显著增加.受害14 d,G3和G9叶生物量在K2处理最大,分别为0.1129 g和0.1186 g;茎和根生物量在K3处理最大,分别为0.1197 g、0.1048 g和0.1217 g、0.1084 g;叶、茎和根生物量的增加率大小依次为根＞茎＞叶,根冠比随施钾量的增加而增加.受害21 d,G3和G9茎生物量在K3处理最大,分别为0.1571 g和0.1595 g;叶和根的生物量在K2处理下最大,分别为0.1461 g、0.1597 g和0.1512 g、0.1699 g;叶、茎和根生物量的增加率为根＞叶＞茎,根冠比随施钾量的增加呈先上升后下降的趋势,在K2处理最大.[结论]在受害程度中等情况下,钾元素促进苜蓿的干物质向贮藏器官(根和茎)分配,以产生补偿生长,而随着受害加重,钾元素调控干物质更多向贮藏器官和光合器官(根和叶)分配,以维持苜蓿的生存并增强了苜蓿对蓟马的耐害性.施钾后,抗蓟马苜蓿甘农9号对蓟马的耐害表现较好,但感蓟马苜蓿甘农3号的施钾效应高于甘农9号.本试验中,K2(0.6g(K2O)/10 kg土)是最佳施钾处理.

白刺粗角叶甲(Diorhabda rybakowi)是严重危害我国西北荒漠草地防风固沙先锋植物唐古特白刺(Nitraria tangutorum)和泡泡刺(N.sphaerocarpa)的主要害虫.利用扫描电子显微镜技术对该虫的触角超微结构进行研究,并比较雌雄种间的差异.结果表明,白刺粗角叶甲雌、雄成虫触角均为丝状,鞭节分为9个亚节,且雄虫触角(4 174.5 μm)显著长于雌虫(3 780.5 μm)(P=0.006).雌、雄虫触角表面均分布有大量表皮孔和鱼鳞状感觉附肢.雌、雄虫共鉴定到6种感器,分为刺形感器、毛形感器、锥形感器、腔锥形感器、耳形感器和Bohm氏鬃毛;其中,腔锥形感器仅在雄虫触角梗节少量分布.这为研究白刺粗角叶甲感知寄主挥发物或性信息素的嗅觉分子机制进而为其综合防控奠定了基础.

为探究施K后苜蓿对N,P,K吸收利用以及苜蓿(Medicago L.)抗蓟马的影响,本试验以'甘农9号'紫花苜蓿为试验材料,于牛角花齿蓟马持续为害14 d和21 d时,评价K0,K1,K2,K3,K4水平下苜蓿的受害指数,测量苜蓿植株叶茎根生物量及N,P,K含量.结果表明:施K后,苜蓿的受害指数显著下降(P＜0.05),在K2水平最低;叶茎根生物量显著增加.施K后,叶中的P,K含量呈升高趋势,N含量呈下降趋势.蓟马为害14 d时,根中的N,P,K含量呈升高趋势;为害21 d时,根中N含量显著降低(P＜0.05),P,K含量(除K3和K4水平)显著低于K0(P＜0.05).施K后,苜蓿叶茎根中N,P,K吸收量均呈升高趋势.随着为害时间持续增加,生物量及N,P,K吸收量向根系分配量增加.K促进了苜蓿对N,P,K的吸收利用及其在各器官中的合理分配,有效提高了苜蓿的补偿生长,增强了苜蓿对蓟马的耐受性.

[目的]明确甘肃省民勤县不同亚类荒漠草地地上昆虫的优势类群及多样性,丰富中国荒漠区域生物多样性保护与持续利用的资料,也为发展和丰富群落生态学研究提供资料.[方法]本研究于2020年和2021年的5-8月,在民勤温性荒漠草地3个亚类草地上,利用网捕、灯诱及陷阱法进行了昆虫种类调查.[结果]共采集昆虫19267头,分属于10目,51科,110种,其中鞘翅目(Coleoptera)为第1大类群,共21科50种,占总种类数的45.45%;鳞翅目(Lepidoptera)为第二大类群,共8科34种,占调查总种数的30.91%.从昆虫在不同亚类草地上的分布来看,沙质荒漠草地上的昆虫9077头,共10目、40科、91种,占总调查个体数的 47.11%,其中鞘翅目为优势类群,占沙质荒漠草地昆虫总个体数的56.41%,其次是鳞翅目,占25.58%;砾质荒漠草地上的昆虫6651头,共7目、36科、71种,占总个体数的34.52%,其中鞘翅目个体数量占砾质荒漠草地昆虫总个体数的73.45%;盐土荒漠草地上的昆虫3539头,共6目、24科、55种,个体数量仅占总调查个体数的18.37%,优势类群为鞘翅目和鳞翅目.沙质荒漠草地昆虫的多样性指数、丰富度指数和均匀度指数最高,三个亚类草地间昆虫优势度指数无显著差异.除沙质荒漠草地和砾质荒漠草地的昆虫物种相似度表现为中等不相似外,其他草地间均表现为中等相似.[结论]砂质荒漠草地的昆虫物种最丰富,砾质草地次之,盐土草地昆虫物种多样性最低;鞘翅目昆虫为3个亚类草地的优势类群.

本研究旨在明确我国北方苜蓿重要害虫——牛角花齿蓟马Odontothrips loti触角感器类型、形态特征及分布特点.利用扫描电镜观察牛角花齿蓟马雌、雄成虫触角的超微结构,比较雌、雄虫之间的差异.结果表明:牛角花齿蓟马雌虫触角长度(314.42±7.21 μm)明显较雄虫(260.58±5.69 μm)长,除柄节和第Ⅰ鞭节外,其他各节雌虫均较雄虫粗大.牛角花齿蓟马成虫触角感器类型共有7种,即B?hm氏鬃毛(BB)、刺形感器(SChⅠ,SChⅡ)、锥形感器(SBⅠ,SBⅡ,SBⅢ)、钟形感器(SCa)、腔锥形感器(SCo)、腔形感器(SCav)和毛形感器(ST),雌虫触角上述7种类型感器均有分布,而雄虫触角上未发现腔形感器.牛角花齿蓟马成虫触角感器在类型、形态特征及分布方面表现雌、雄个体差异.本研究为深入探究牛角花齿蓟马触角感器的嗅觉通讯机制提供形态学基础.

为明晰高原鼢鼠干扰对大型土壤动物类群分布和功能群特征影响,选取祁连山东段高原鼢鼠典型分布高寒草甸,依据鼠丘密度将研究区划分4个干扰梯度,调查各干扰区植物、群落结构、土壤理化性质和大型土壤动物功能群组成.采用冗余分析方法探讨植物土壤因子对土壤动物功能群组成和分布的影响.结果表明:研究区植食性土壤动物为优势功能群,极重度干扰区植食性功能群丰富度和Shannon多样性指数显著高于中度和重度干扰区(P＜0.05);高原鼢鼠干扰对高寒草甸土壤动物群落稳定和相似性影响较小;冗余分析表明土壤温度、紧实度、全氮和全钾以及莎草科生物量和植物物种均匀度均显著影响高寒草甸土壤动物功能群的空间分布(P＜0.05),其中土壤温度对土壤动物功能群分布影响最为显著.

Alfalfa (Medicago sativa L.) is one of the most important quality forages worldwide and is cultivated throughout China. Alfalfa is susceptible to a variety of viral diseases during its growth, which has caused huge amounts of commercial losses. However, the profile of the alfalfa virus in China remains ambiguous and the viruses transmitted by Odontothrips loti (Haliday), dominant insect pests in alfalfa, are also poorly understood. In the present study, virus diversity was investigated in the primary alfalfa-growing areas in China. A total of 18 alfalfa viruses were identified through RNA-sequencing (RNA-seq) and reverse transcription-polymerase chain reaction (RT-PCR). Two new plant viruses, Medicago sativa virus 1 (MsV1) and Medicago sativa luteovirus 1 (MsLV1), were detected for the first time. Another four viruses, including the Alfalfa ringspot-associated virus (ARaV), Alfalfa virus F (AVF), Alfalfa enamovirus 1 (AEV1), and Alfalfa deltaparitivirus (ADPV), were reported in China for the first time as well. Both Alfalfa mosaic virus (AMV) and Medicago sativa alphapartitivirus 2 (MsAPV2) are the dominant pathogens, with an infection incidence of 91.7–100%, and 74.4–97.2%, respectively. Additionally, O. loti with first- and second-instar nymphs were shown to acquire the AMV within 0.25 h of feeding on a virus-infected alfalfa. Transmission by thrips to healthy alfalfa plants was also demonstrated. Additionally, we clarified the dynamic changes in the AMV in pre-adult stages of O. loti, which indicated that the AMV is propagated in the nymph stage of O. loti. These findings provide valuable information for understanding the alfalfa virome, confirm the role thrips O. loti plays in alfalfa virus transmission, and improve our fundamental knowledge and management of diseases in China.

为了探索施钾对苗期紫花苜蓿抗蓟马的影响及其光合机制,以甘农9号(Medicago sativa cv.Gannong No.9)和甘农3号(M.sativa cv.Gannong No.3)紫花苜蓿为材料,设置40,60,80和100 mg/kg 4个钾水平,以不施钾为对照(CK),评价了各钾水平下不同蓟马为害时间的苜蓿的受害程度,并测定了不同施钾水平下苜蓿功能叶片的光合特性和叶绿素含量.结果 表明:施钾后,苜蓿受蓟马为害的程度显著减轻;苜蓿叶片叶绿素含量升高,但随着蓟马为害时间的延续,苜蓿的叶绿素含量较受害前期降低.为害7d时,甘农3号苜蓿净光合速率(Pn)和水分利用率(WUE)升高、气孔导度(Gs)显著升高,除K1水平外,胞间CO2浓度(Ci)在其他施钾水平下均显著升高,除K4水平外,蒸腾速率(Tr)在其他施钾水平下均降低;甘农9号苜蓿的净光合速率、气孔导度、胞间CO2浓度均显著升高,水分利用率升高,蒸腾速率降低.为害14d时,两个苜蓿品种的净光合速率、气孔导度均显著升高,蒸腾速率降低;甘农3号的水分利用率升高不显著,甘农9号的水分利用率显著升高;除K3水平外,甘农3号的胞间CO2浓度在其他钾水平下均升高,除K4水平外,甘农9号的胞间CO2浓度在其他钾水平下均显著降低.施钾使苜蓿叶片的叶绿素含量增加,提高了苜蓿的光合能力,进而增强了苜蓿对蓟马的抗性.

[目的]为了探讨施钾对苜蓿上牛角花齿蓟马Odontothrips loti的产卵选择、生长发育、成虫寿命和繁殖力的影响,明确施钾苜蓿叶片营养物含量与牛角花齿蓟马生命参数的关系.[方法]在不同钾量(40,60,80和100 mg/kg)处理下(以不施钾作为对照),观察记录牛角花齿蓟马在紫花苜蓿品种甘农3号Medicago sativa cv.Gannong No.3叶片上的产卵量,幼期各龄期发育历期和存活率以及二代成虫的寿命和繁殖力,同时测定不同施钾量下苜蓿叶片的可溶性糖、游离氨基酸及钾含量.[结果]随着施钾量的增加,牛角花齿蓟马在苜蓿叶片上的产卵量(粒/复叶)先降低后升高,在60 mg/kg钾处理降幅最大,较对照降低了 45.58％;卵孵化率和1-2龄若虫的存活率变化不显著,但3-4龄若虫的存活率和幼期总存活率显著下降,分别在100 mg/kg和80 mg/kg钾处理下降幅最大,较对照分别下降了 54.36％和48.48％.不同施钾量下苜蓿叶片上牛角花齿蓟马卵和1-2龄若虫发育历期无显著变化,3-4龄若虫及幼期总发育历期均延长;牛角花齿蓟马二代成虫的繁殖力均显著下降,成虫寿命显著缩短(40 mg/kg钾处理除外).施钾后,苜蓿叶片可溶性糖含量、钾含量和糖氮比增大,游离氨基酸含量减少.相关关系分析表明,苜蓿叶片钾含量与牛角花齿蓟马幼期总存活率和成虫繁殖力无显著相关性,而苜蓿叶片可溶性糖含量和糖氮比均与3-4龄若虫存活率和繁殖力极显著负相关,与幼期总存活率呈显著负相关.[结论]施钾苜蓿对牛角花齿蓟马成虫产卵产生显著的排趋性;施钾提高了苜蓿叶片的可溶性糖含量及糖氮比,不利于若虫的生长发育,并使成虫寿命缩短、繁殖力下降,对牛角花齿蓟马产生了显著的抗生作用.

为了探究施氮对苜蓿抗蓟马的影响,本试验在大田网室盆栽条件下,以'甘农3号'和'甘农9号'苜蓿品种为材料,以牛角花齿蓟马Odontothrips loti为研究对象,设4个施氮处理(N1,N2,N3,N4)和1个不施氮的对照,评价不同施氮水平下苜蓿的受害程度,并测定苜蓿根茎叶生物量和可溶性糖含量.结果 表明:1)施氮后2个苜蓿品种的受害指数均升高;受牛角花齿蓟马为害7d后,2个苜蓿品种的受害指数均在N2处理下最高,分别比对照高39.93％和20.06％;受害14 d后,'甘农3号'的受害指数在N3处理下最大,比对照高28.51％,'甘农9号'的受害指数在N1处理下最大,比对照高23.97％;在同一施氮水平下,'甘农3号'的受害指数均明显高于'甘农9号'.2)施氮后2个苜蓿品种根茎叶的生物量增加,但叶茎比和根冠比降低,生物量更多向茎秆中分配,向叶片和根系中分配较少.3)苜蓿叶片中的可溶性糖含量随施氮量的增加而减少,而茎秆和根系中的可溶性糖含量升高.施氮降低了苜蓿对牛角花齿蓟马的抗性,促进了苜蓿根茎叶的生长,但根冠比下降,致使苜蓿的再生能力和耐虫性下降;施氮后苜蓿叶片中的可溶性糖含量下降,使叶片合成防御物质的碳源不足,进而导致苜蓿对蓟马的抗性降低.

分析了甘肃农业大学草业科学本科专业核心课程"草地昆虫学"理论和实践教学模式中存在的问题,并提出教学改革措施.首先,理论课程采用线上线下混合教学方式,将课程思政和专业知识相结合,实现以学生为主体的课堂教学目的.其次,实践课程通过优化实验和实习内容,侧重过程性指导,不断提升学生的综合实践能力.最后,鼓励学生参加科研训练和学科竞赛,并建立课程综合考评机制,增强学生的学习主观能动性.通过对该课程的教学改革,培养学生的创新思维,促进综合能力的提升.