不同栽培模式下冬小麦籽粒糖及淀粉累积的动态研究

以冬小麦小偃22为试验材料,在120 kg/hm2施氮水平和基本苗为130~150万hm2下,研究常规栽培(CK)、覆草栽培、地膜覆盖3种不同栽培模式灌浆期小麦籽粒可溶性总糖含量、蔗糖含量及淀粉累积的动态变化。试验结果表明,不同栽培模式小麦籽粒可溶性总糖含量、蔗糖含量、淀粉含量存在差异。与常规栽培相比较,在覆草栽培条件下,可溶性总糖含量、蔗糖含量在灌浆前期高于常规栽培,在成熟期低于常规栽培;而淀粉含量始终高于常规栽培,且籽粒的饱满指数和产量均显著高于常规栽培。地膜覆盖栽培条件下,可溶性总糖含量、蔗糖含量在灌浆前期高于常规栽培,在成熟期低于常规栽培;而淀粉含量始终高于常规栽培,且籽粒的饱满指数和产量均高于常规栽培。在覆草和地膜覆盖栽培条件下冬小麦器官中可溶性总糖、蔗糖的合成代谢旺盛,可溶性总糖含量、蔗糖积累量高,"库"器官中可溶性总糖、蔗糖供应充足,可溶性总糖、蔗糖的降解代谢旺盛,具有较强的同化物利用能力,为籽粒中淀粉的快速积累以及最终实现较高的粒重和产量奠定了基础。     

抗旱小麦籽粒灌浆期旗叶衰老与活性氧代谢研究

以3种抗旱品种长武134、铜麦3号、西农794为供试材料,研究干旱条件下小麦旗叶衰老与活性氧代谢特征。试验结果表明,灌浆期不同抗旱性品种小麦旗叶衰老和活性氧代谢存在差异。与长武134和铜麦3号相比较,西农794的叶绿素含量较高且降低趋势最缓慢;开花后第14天长武134的过氧化物酶(POD)和过氧化氢酶(CAT)活性较高,后期活性降低快,西农794两种酶活性在灌浆后期含量较高,降低速度慢,持续时间长;整个灌浆期间西农794的丙二醛含量最少,膜质过氧化程度最低,叶片衰老程度最慢。     

长期水分胁迫对夏玉米根叶保护酶活性及膜脂过氧化作用的影响

利用防雨旱棚研究了水分胁迫对夏玉米根系及叶片保护酶活性及脂膜过氧化作用的影响。结果表明在水分胁迫下,玉米根系与叶片保护酶SOD、CAT、POD活性均在生长发育前中期显著升高而后期下降。即保护酶系统对水分胁迫响应的策略不同,前中期如大口期和抽雄前期主要表现为积极应对,后期如灌浆期和乳熟期主要表现为被动忍耐;根系SOD、CAT和POD活性小于叶片。SOD、CAT、POD活性对水分胁迫的敏感程度不同,SOD对水分胁迫不敏感,水分胁迫后期,SOD仍有较高活性,POD活性则明显降低。膜脂过氧化产物MDA含量随水分胁迫程度加剧而增加,且根系MDA含量小于叶片MDA含量。在水分胁迫下,叶片与根系的可溶性蛋白质含量降低。研究还表明,在水分胁迫下,玉米根系保护酶活性及膜脂过氧化作用对水分胁迫的反应与叶片保护酶活性及膜脂过氧化作用对水分胁迫的反应呈正相关关系,且绝大多数的相关系数达显著或极显著水平。     

干旱条件下糜子叶片衰老与保护酶活性变化

在干旱棚栽培条件下以宁糜13号、内糜5号和晋糜4号糜子品种为材料,观测分析不同品种花后叶片叶绿素含量、保护酶活性(SOD、CAT、POD)以及丙二醛含量变化。结果表明,参试品种各功能叶片叶绿素含量及SOD、CAT、POD活性均在开花14 d后逐渐下降,MDA含量随着叶片的衰老而升高;参试品种叶片衰老的总体变化趋势一致,但衰老进程存在差异。与内糜5号和晋糜4号相比,宁糜13号叶绿素下降幅度小,各功能叶片衰老过程中SOD、CAT活性下降较慢,POD活性下降较快,MDA含量增加幅度小,叶片功能期长,衰老缓慢,有利于光合产物的积累;干旱条件下,叶绿素含量、过氧化氢酶CAT、超氧化物歧化酶SOD与单株产量呈正相关,而过氧化物酶POD、丙二醛MDA与单株产量呈负相关。     

干旱条件下冬小麦籽粒灌浆期冠层叶片衰老特性研究

以冬小麦品种西农961、小偃6号、陕229为供试材料,研究了干旱条件下冬小麦不同品种冠层叶片衰老特性。试验结果表明,籽粒灌浆期冬小麦不同品种叶片衰老特性存在差异。与西农961和小偃6号相比较,陕229的叶绿素含量较高且降低趋势最缓慢;3个品种在开花后可溶性蛋白含量均呈现先升高后降低的趋势,在开花后第12 d达到最大值,其中陕229的可溶性蛋白质含量在灌浆中期降低速率较为缓慢;陕229的过氧化氢酶(CAT)活性在灌浆后期较高,降低速度慢,持续时间长;整个灌浆期间陕229的丙二醛含量最少,膜质过氧化程度最低,叶片衰老程度最慢。     

高浓度臭氧对春小麦膜脂过氧化和抗氧化系统的影响

利用开顶式气室(OTC)研究了高浓度O3对春小麦叶片膜脂过氧化程度、活性氧含量、抗氧化系统的影响。结果表明,随着臭氧浓度的升高,不同生育时期小麦叶片的相对电导率、MDA含量显著上升(P<0.01);穗粒重明显下降(P<0.05);O2-.产生速率和H2O2含量显著增加(P<0.05)。SOD活性、CAT活性、POD活性随生育进程和O3浓度升高而显著下降。而对抗氧化物如类Car含量、ASA含量的影响不显著。臭氧浓度增加,促使小麦叶片膜的伤害,引发了膜脂过氧化作用,产生了过多的活性氧自由基,破坏了抗氧化系统功能,影响了叶片的正常生理代谢。     

玉米灰斑病抗性机制中活性氧代谢的作用

研究了玉米灰斑病菌侵染四个抗病和感病的玉米品种时，叶片内部活性氧代谢酶及细胞过氧化产物含量的动力学变化。结果表明，抗、感病品种的SOD、CAT及POD酶活性在病茵侵染后都变化显著，抗病品种各酶活性变化幅度比感病品种大。叶片内过氧化产物MDA含量则相反，抗病品种沈试29在接种第13天时叶片MDA含量只为18．46nmol／g，而感病品种铁单9为23．14nmol／g，抗病品种比感病品种增加幅度小。说明活性氧代谢在植物抗病机制中起着重要作用，抗病品种对活性氧代谢的酶调节能力强，病菌侵染后细胞过氧化程度低，在痛菌侵染时活性氧清除酶活性最大增加值与发病程度呈显著正相关。     

水分胁迫下不同耐旱性糜子叶片保护酶活性及膜脂过氧化特性

选取耐旱品种陇糜4号和旱敏感品种晋黍7号,利用防雨旱棚与人工控水相结合的方法,研究了水分胁迫对糜子产量、叶片保护酶活性及膜脂过氧化作用的影响。结果表明,与CK处理相比,水分胁迫降低了糜子的穗数、穗粒数和千粒重,重度水分胁迫下差异达显著（P<0.05）水平,且旱敏感品种晋黍7号的降低幅度大于耐旱品种陇糜4号。整个生育时期,糜子叶片的SOD、POD和CAT活性表现为先升高后降低的趋势,在抽穗期达到最大值; 水分胁迫降低了糜子叶片的SOD、POD和CAT活性,与对照相比,重度水分胁迫下达到显著性差异（P＜0.05）,重度水分胁迫下,耐旱品种陇糜4号SOD活性2年内平均降低22.58%,而旱敏感品种晋黍7号2年内平均降低44.94%。水分胁迫处理增加了糜子叶片的膜脂过氧化产物MDA含量和可溶性糖的含量,随着生育期的推进,糜子叶片可溶性糖含量表现为先升后降的趋势,在灌浆期表现为最大值。相关性分析结果表明,糜子产量与叶绿素含量、SOD活性、POD活性和CAT活性呈正相关关系。     

糜子叶片衰老与活性氧代谢研究

以榆糜3号为试验材料,研究糜子叶片衰老与活性氧代谢特性。结果表明,随着植株衰老,不同叶位超氧化物歧化酶、过氧化氢酶、过氧化物酶等保护性酶活性呈由高到低的变化趋势,旗叶活性氧保护酶含量高且下降缓慢,丙二醛含量低且增长缓慢,在籽粒灌浆中后期表现更为明显。研究认为,在旱作农业生产中,延缓叶片衰老,对促进糜子籽粒充实,提高糜子产量和品质具有重要作用。     

不同基因型荞麦生育后期叶片衰老特性研究

大田条件下试验观测甜荞西农9976和苦荞西农9920两种不同基因型荞麦开花至成熟期闻主茎叶片衰老特性.结果表明,不同基因型荞麦叶片衰老进程存在着明显差异.与甜荞西农9976相比,苦荞西农9920生育后期功能叶片的叶绿素含量和可溶性蛋白质含量下降幅度小,SOD、CAT活性下降缓慢,MDA含量增加幅度小,叶片功能期长,衰老慢,有助于光合产物的积累.生产实践中,有效控制或延缓荞麦开花节叶片的衰老进程,延长叶片功能期,对提高荞麦产量有十分重要的作用.     

Investigation of the Mode of Action of Nematode Neuropeptides

The neuropeptide AF2 has a complex set of actions on the dorsal muscle strip of Ascaris suum, including a potentiation of the acetylcholine-stimulated muscle contraction. Caffeine at 100 μm and 5 mm inhibited this potentiation, as did 100 μm theophylline in two out of six studies. The cyclic-AMP-potentiating compounds IBMX, dibutyryl cAMP and forskolin had no effect on the AF2-induced potentiation of the acetylcholine-stimulated muscle contraction. These preliminary data suggest that the potentiating action of AF2 is not mediated by a cAMP pathway.     

厚朴病虫害种类的初步调查

采用标准地法和线路调查法,对湖北恩施市新塘乡双河厚朴基地的厚朴病虫害进行了系统调查,记录主要虫害13种,其中叶部害虫9种,枝干害虫2种,根部害虫2种。厚朴主要病害5种。藤壶蚧、厚朴枝角叶蜂和厚朴新丽斑蚜为湖北省首次报道,小绿叶蝉为厚朴新寄主记录种。同时记录了藤壶蚧的天敌6种,其中寄生小蜂2种,瓢虫4种;厚朴新丽斑蚜的天敌昆虫8种。对藤壶蚧、厚朴枝角叶蜂和厚朴苗木根腐病等重要病虫害的发生规律进行了初步调查,同时提出了防治建议。     

Effects of timing and method of application of Penicillium oxalicum on efficacy and duration of control of Fusarium wilt of tomato

The effects of timing and method of application of Penicillium oxalicum on the control of fusarium wilt of tomato were investigated. Application of P. oxalicum to tomato seedlings in seedbeds reduced disease caused by Fusarium oxysporum f.sp. lycopersici in a growth chamber by 45–49% and in glasshouse experiments by 22–69%. Disease suppression was maintained for 60–100 days after inoculation with the pathogen in the glasshouse. No disease reduction was observed in tomato plants where P. oxalicum was applied to seeds. Treatment with P. oxalicum did not affect the population of F. oxysporum f.sp. lycopersici in the rhizosphere.     

棉花黄萎病菌致病型的AFLP分析

 选用41个棉花黄萎病菌(Verticillium dahliae)代表菌系,在温室条件下,对4个棉花品种鄂荆1号(感)、中棉所12(耐)、文-5(抗)和唐棉2号(抗)进行致病性测定,结果可将供试菌系分为落叶型与非落叶型2类。选取8对AFLP引物PCR扩增的结果中,统计带型稳定、清晰且有多态性的条带,共169条作系统聚类分析,将上述菌系分为2大类,第一类为非落叶型菌系,包括10个非落叶型菌系和1个过渡菌系;第二类为30个落叶型菌系。根据聚类分析建立树状图,发现菌系与地理来源存在一定的相关性,而依据菌系致病力强弱分类则相关关系不大。选用25对EcoRⅠ和MseⅠ引物组合,对供试的41个V.dahliae进行AFLP扩增,筛选到2对引物E64(GACTGCGTACCAATTCGAC)、M53(GATGAGTCCTGAGTAACCG)和E49(GACTGCGTACCAATTCCAG)、M65(GAT-GAGTCCTGAGTAAGAG),能分别扩增出433bp和110bp2条仅为V.dahliae非落叶型菌系独有的特异片段,可将落叶型与非落叶型菌系分开,这2条特异片段被命名为EM₄₃₃和EM₁₁₀。     

青稞种子带菌检测及杀菌剂消毒处理效果

为了研究青稞种子外部和内部携带真菌情况,比较不同杀菌剂对青稞种子的带菌消毒效果和对幼苗生长的影响,为青稞种子播前包衣处理和种传真菌病害防控提供依据,采用离体平皿法对云南迪庆‘云青1号’、‘云青2号’和‘短白青稞’3个主栽品种进行带菌检测,并对种子进行拌种或浸种处理测定6种杀菌剂对种子消毒效果,分析杀菌剂对种子发芽和幼苗生长的影响。结果表明:供试青稞种子表面携带的优势菌群为青霉(Penicilliumspp.)、镰刀菌(Fusariumspp.);种子内部寄藏的真菌主要为镰刀菌、核腔菌(Pyrenophoraspp.)、附球菌(Epicoccumspp.)、丝核菌(Rhizoctoniaspp.)、链格孢(Alternariaspp.)和木霉(Trichoderma spp.)。青稞不同品种的种子表面及内部携带的真菌种类差异较大。致病性测定表明,镰刀菌对种子萌发和幼苗生长影响最大,后期出现幼苗坏死现象。45%咪鲜胺EW、75%百菌清WP、50%福美双WP对青稞种子携带真菌均有显著抑制作用和消毒效果,50%福美双WP消毒效果最优,达100%;45%咪鲜胺EW、75%百菌清WP、50%福美双WP处理对青稞种子发芽和幼苗生长均无显著影响。     

Mode of action of etoxazole

The mode of action of the 2,4-diphenyl-1,3-oxazoline acaricide/insecticide etoxazole has been argued to be moulting inhibition, but experimental results supporting this hypothesis are lacking. This study investigated the effect of etoxazole on chitin biosynthesis in the fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). Etoxazole induced moulting defects in fall armyworm larvae similar, if not identical, to those caused by benzoylphenylureas, a well-known class of insecticidal chitin biosynthesis inhibitors. Furthermore, in contrast to untreated larvae, the chitin content in the integuments of larvae several days after treatment did not differ from that in freshly ecdysed individuals, thus suggesting strong chitin biosynthesis inhibition in vivo. A more detailed investigation of the inhibitory potential by incubating cultured integument pieces from larvae of S. frugiperda with [14C]N-acetyl-D-glucosamine, a radiolabelled chitin precursor, revealed I50 values of 2.95 and 0.071 microM for etoxazole and triflumuron respectively. The incorporation of radiolabel into potassium hydroxide-resistant material was inhibited by etoxazole in a dose-dependent manner. Based on these results, it is concluded that the acaricidal and insecticidal mode of action of etoxazole is chitin biosynthesis inhibition.     

百合地下害虫主要种类调查及生物（源）农药筛选

调查了甘肃省临洮县为害百合的地下害虫种类, 并以主要发生为害种类为供试对象, 采用拌土法测定了几种生物（源）农药对主要害虫的室内毒力和致死中时。调查发现小云斑鳃金龟Polyphylla gracilicornis、棕色鳃金龟Holotrichia titanis为主要发生及为害种类, 不同时间发生种类存在差异, 9月份以小云斑鳃金龟幼虫发生为害为主, 发生量占地下害虫总数的66.16%, 平均种群密度为10.48头/m2, 10月份, 则以棕色鳃金龟幼虫发生为主, 发生量占地下害虫总数的96.86%, 平均种群密度为7.79头/m2, 主要取食百合根系和鳞茎, 造成根系数量减少, 鳞茎出现不规则褐色缺口或凹陷斑。药剂筛选结果表明, 1.8%阿维菌素乳油、200亿孢子/g球孢白僵菌粉剂对两种蛴螬均具有较高的杀虫活性和速效性, 药后7 d时, 校正死亡率在82.22%以上, 对小云斑鳃金龟幼虫和棕色鳃金龟幼虫的LC50分别为0.161、0.060 mg/g和5.558×107、0.362×107孢子/g, LT50分别为2.237 d（2.2 mg/g）、1.393 d（2.2 mg/g）和6.645 d（40.0×107孢子/g）、4.940 d（2.0×107孢子/g）, 这两种生物（源）农药对两种蛴螬的LC50和LT50值均略大于两种化学农药25%二嗪磷乳油、40%辛硫磷乳油处理的, 且对小云斑鳃金龟幼虫的杀虫活性均低于对棕色鳃金龟幼虫的杀虫活性, 致死中时则长于对棕色鳃金龟幼虫的致死中时。     

黑麦草属DNA条形码鉴定技术研究

以毒麦、田毒麦、多花黑麦草、多年生黑麦草、硬直黑麦草、高羊茅与狗牙根等禾本科的7种植物为材料,拟采用 DNA 测序、特异性位点比对、种间遗传距离测定、建立系统树等分析候选 DNA 条形码 psbA-trnH 鉴别黑麦草属常见植物的能力。实验结果表明,以 psbA-trnH 为 DNA 条形码时,建立的系统发育树能较好区分毒麦和田毒麦与其他几种植物。psbA-trnH 序列可以作为黑麦草属植物的潜在条形码。     

Effects of different temperature treatments on dormancy of sclerotia of ten isolates of Sclerotium cepivorum

The variability of dormancy of sclerotia of ten isolates ofSclerotium cepivorum was investigated. Of all isolates tested, the freshly harvested sclerotia were dormant. After drying for 48 hours the sclerotia of six isolates were able to germinate, two isolates stayed dormant and two isolates were infested by hyperparasitic fungi. After storage in soil at 5°C or 20°C, the sclerotia of the different isolates exhibited considerable differences in respect to germination capability, but all isolates showed highest germination after a treatment of 8 weeks at 20°C followed by 8 weeks at 5°C. The sclerotia of all isolates showed an increased capacity to germinate withoutAllium extracts at 10°C after pretreatment at 30°C for 28 days.     

Allelopathy of buckwheat: Assessment of allelopathic potential of extract of aerial parts of buckwheat and identification of fagomine and other related alkaloids as allelochemicals

The allelopathic potential of buckwheat ( Fagopyrum esculentum ) was investigated. Field study showed that living buckwheat reduced weed biomass compared with plots without buckwheat. Laboratory study revealed that root exudates suppressed root and shoot growth of weeds and reduced weed dry weight. Sequential partitioning of the aqueous ethanolic extract of the aerial parts of buckwheat showed that the chloroform extract caused an 80% reduction in radicle elongation of lettuce seedlings at a concentration of less than 100 p.p.m. Fagomine, 4-piperidone and 2-piperidinemethanol were isolated and identified by ¹H and ¹³C nuclear magnetic resonance from the chloroform extract. These compounds caused a 50% inhibition of radicle elongation in lettuce seedlings at concentrations of less than 100 p.p.m. These results suggest that compounds 1, 2, and 3 might act as allelochemicals and affect the growth or germination of different plant species.