调亏灌溉对夏玉米根冠生长关系的调控效应

以夏玉米(zea may L. cv.)为试验材料,采用防雨棚下桶栽土培方法,进行调亏灌溉(Regulated deficit irrigation,RDI)对根、冠生长的影响研究,旨在寻求适宜的水分调亏阶段和调节亏水度,为建立节水高产、优质高效作物RDI模式提供技术参数。试验采用二因素随机区组设计,设置4个水分调亏阶段:三叶～拔节(Ⅰ),拔节～抽穗(Ⅱ),抽穗～灌浆(Ⅲ),灌浆～成熟(Ⅳ);每个调亏阶段设置3个水分调亏度:轻度调亏(L)、中度调亏(M)和重度调亏(S),土壤相对含水率分别为60%～65%FC(Field capacity)、50%～55%FC和40%～45%FC;设全生育期保持适宜土壤水分(75%～80%FC)作为对照(CK)。分别在水分调亏期间和复水后测定各处理根系参数和地上干物质质量。结果表明,玉米生长中、后期水分调亏具有促进根系发育和减缓根系衰亡的"双重效应",反映出玉米根系在生育后期比生育前期对水分适应能力强的特性。玉米根冠比(R/S)受水分影响最大的阶段是三叶-拔节期,受水分影响最小的阶段是灌浆期;拔节-抽穗期水分调亏期间能显著增大R/S,复水后分配到冠层与根系的物质比较平衡,维持较为适宜的R/S,表明此阶段为通过RDI调控玉米R/S的适宜阶段。玉米三叶-拔节期水分调亏改善了穗部性状,表明在作物营养生长阶段的适度水分调亏有利于作物生殖生长。RDI可以有效调控根/冠生长关系,提高经济产量。     

植物样品中盐分离子的几种分析方法比较

采用三酸混合消化法及沸水提取法制备待测液,用化学一法、等离子光谱法、离子色谱法对四种植物中的Ｋ＾＋、Ｎａ＾＋、Ｃａ＾２＋、Ｍｇ＾２＋四种阳离子和Ｃｌ＾－、ＳＯ４＾２－两种阴离子的含量进行分析比较。我们的结果表明：采用酸解法和沸水提取法制备待测液对于样品中的Ｋ＾＋、Ｎａ＾＋、Ｍｇ＾２＋三种阳离子的测定结果没有显著差异;但采用沸水提取法测得的Ｃａ＾＋的含量明显小于酸解法制备待测液。采用化学滴定法、等离     

调亏灌溉对荒漠绿洲膜下滴灌马铃薯生长、产量及水分利用的影响

以马铃薯品种青薯168为研究材料,研究了膜下滴灌条件下不同生育期土壤水分亏缺对马铃薯生长、薯块产量与水分利用等指标的影响。在不同生育阶段设置了8个水分亏缺处理(RD1~RD8)和1个充分灌水处理(CK)。结果表明:膜下滴灌调亏灌溉马铃薯产量、收获指数、水分利用效率、灌溉水利用效率等指标受水分亏缺影响显著,块茎形成期轻度水分亏缺RD1效果最佳,产量略有下降,但其水分利用效率、灌溉水利用效率与收获指数分别较其他处理及对照高8.10%~41.57%、3.57%~42.62%、10.16%~34.38%;水分亏缺影响马铃薯各生育阶段耗水量,且亏缺程度越大,生育阶段消耗的水量减少越明显;全生育期马铃薯光合势和叶面积指数变化趋势基本一致,即生育前期缓慢上升,中期快速上升,后期缓慢下降,总体呈现单峰曲线。因此,适度水分亏缺有利于提高膜下滴灌马铃薯产量、水分利用效率、灌溉水利用效率,促进马铃薯生长并改善其水分利用状况。     

近滨海缺水盐渍区冬小麦返青期灌水对土壤脱盐及产量的影响

近滨海缺水盐渍区冬小麦返青期灌水试验表明,当每公顷浇水量为７５０ｍ＾３时,０ ｃｍ～２０ｃｍ耕层土壤ＨＣＯ３＾－,ＣＩ＾－,ＳＯ４＾２－,Ｃａ＾２＋,Ｍｇ＾２＋,Ｎａ＾＋＋Ｋ＾＋盐离子含量分别下降３．５０％,５０．０４％,６７．７６％,４１．１５％,３８．８９％和２９．５９％,淋脱量大小顺序为：ＳＯ４＾２－〉ＣＩ＾－〉Ｃａ＾２＋〉Ｍｇ＾２＋〉Ｎａ＾＋＋Ｋ＾＋〉ＨＣＯ３＾－,耕层脱盐率４２．１７％。浇水处理,返青期灌水１０ｄ后单株人蘖数与干物重分别比对照增加１．２条,０．０９ｇ;灌浆期绿叶面积增加３．９５ｃｍ＾２;成熟期株高、穗数、穗粒数和千粒重分别比对照增加６．９ｃｍ,１８０．０万／ｈｍ＾２,３粒和２．２３ｇ,增产６８．４０％,其中分蘖数、穗数和产量与对照的差异达极显著水平,灌浆期单株绿叶面积达显著水平。     

Ca2+对水分胁迫下小麦诱导蛋白产生的影响

水分胁迫及ＡＢＡ处理可诱导丰抗８号小麦幼苗及其悬浮培养细胞中４４．２ＫＤ蛋白亚基的产生或大量合成。高浓度的Ｃ＾２＋通道阻塞剂处理丰抗８号小麦幼苗,可明显抑制水分胁迫诱导产生的４４．２ＫＤ蛋白亚基的大量合成,而悬浮培养细胞中,２０μＭ的异博定处理就可显著抑制由ＡＢＡ及ＡＢＡ＋ＰＥＧ所诱导的蛋白亚基含量的提高,说明Ｃａ６２＋可能参与了干旱信号在胞内的传递过程;     

氮、磷、钾施肥配比对红枣光合特性与水分利用效率的影响研究

不同氮磷钾处理条件下研究红枣光合特性及其水分利用效率的变化.结果表明:不同氮磷钾组合对枣树叶片叶绿素含量、叶面积指数以及光合特性和水分利用效率都产生了明显的影响.在磷钾适度的条件下,随着氮素施入量的增加,叶绿素含量先增后减,叶面积指数、净光合速率峰值和最小值都随氮素施入量的增加而升高,蒸腾速率和气孔导度值在日变化的各个...     

苏云金素对东亚小花蝽捕食作用的影响

采用二次回归最优设计，研究苏云金素对东亚小花蝽捕食作用的影响，得出日均捕食量（ｙ）与猎物（ｘ１）和捕食者（ｘ２）之产作关系模型。处理捕食数量回归方程：ｙ＝－０＼００２１ｘ１＾２＋１．２１１ｘ２＾２＋０．８８２２ｘ１－１０，３４６５ｘ２－０．０６４９ｘ１ｘ２＋１．７１７４；对照捕食数量回归方程：ｙ＝－０．００１７ｘ１＾２＋０．７７３４ｘ２＾２＋０．６９４１ｘ１－６．４９１４ｘ２－０．０４７４ｘ１ｘ２     

向日葵的水肥效应与合理施肥研究

在陕西渭北合阳旱农试区，进行施肥对向日葵水分利用效率影响和向日葵施肥模式的研究，结果表明，在Ｎ，Ｐ，Ｋ施用量小于１３５ｋｇ／ｈｍ＾２的范围内，向日葵的水分利用效率随着施肥量的增加而提高。施肥对向日葵的产量效应Ｋ〉Ｎ〉Ｐ，经济效益最佳施肥量为Ｎ１６７．１７ｋｇ／ｈｍ＾２，Ｐ２Ｏ５１２９．０９ｋｇ／ｈｍ＾２，Ｋ２Ｏ１８５．６３ｋｇ／ｈｍ＾２。     

不同温度对甜菜夜蛾实验种群的影响

报道了不同温度下甜菜夜蛾卵、幼虫和蛹的发育历期、发育速率、发育起点温度及有效积温。该虫卵孵化率、幼虫存活率、蛹羽化率和种群趋势指数与温度变化的回归关系分别为：ＳＥ＝－７６．７７＋１２．４８８８Ｘ－０．２４６５Ｘ＾２;ＳＬ＝－９９．１０３７＋１４．５４３８Ｘ－０．２７９Ｘ＾２;ＳＰ＝２９．８０２２＋９．２５６Ｘ－０．１７５６Ｘ＾２和Ｉ＝１１４４．９５７＋１０１．０１３Ｘ－１．９７１６Ｘ＾２。在２４－     

渗透胁迫下磷对玉米叶片有机渗调物质的影响

选用高水肥型玉米品种，以ＰＥＧ胁迫水培法控制不同的水分变化，用Ｈｏａｇｌａｎｄ全营养液和无磷营养液控制磷水平，测定了三叶期以后的玉米叶片中可溶性糖，蔗糖，游离氨基酸总量主脯氨酸含量的变化。结果表明，干旱胁迫下磷对４种有机渗调物质的积累理和引起急剧变化的时间有羊显著的影响。通过多次干湿间歇变水处理，有磷处理表现出较强的恢复能力，对再度干旱胁迫也具有较好的适应性。     

Localization of metabolic sites of action of herbicides

Time- and concentration-course studies were conducted to determine the effect of thirteen herbicides on photosynthesis, respiration, RNA synthesis, protein synthesis, and lipid synthesis using isolated single leaf cells. Each herbicide was from a different chemical class. Appropriate ¹⁴C-substrates and product purification procedures were used for each process prior to liquid scintillation counting. The most sensitive metabolic site of inhibition was photosynthesis for atrazine, bromacil, dichlobenil, monuron, and paraquat; RNA synthesis for dalapon and dinoseb; protein synthesis for chlorpropham; and lipid synthesis for CDAA, chloramben, 2,4-D, EPTC, and trifluralin. However, with several herbicides, one or more process was almost as sensitive as the one mentioned above. All herbicides inhibited more than one process, and the most sensitive site of inhibition may not be the same process that was inhibited the greatest at the maximum concentration and maximum exposure time used. Therefore, a concept of metabolic sites of action, rather than a primary site of action, appears to be more meaningful for herbicides.     

福寿螺配偶个体大小选择性初步观察

通过野外观察与实验研究,掌握了福寿螺的婚配体制及其配偶选择性规律。福寿螺与多数低等动物一样,其婚配属于乱交制,无固定配偶;雌螺对与其交配的雄螺个体大小没有选择性,而雄螺对雌螺的个体大小有选择性,倾向于与较大个的雌螺交配。     

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。     

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.     

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.     

Mode of action of meturine

The effect of meturine on the light processes of photosynthesis was studied.Meturine is a herbicide for weed control in potato and cotton crops. It is a N-phenyl—N-hydroxy—N′-methylurea.The experiments were carried out on isolated pea and spinach chloroplasts.When examining photosystem I, reduced DPIP was used as an electron donor, whereas methyl-viologen served as an electron acceptor. When examining photosystem II, DPIP represented the electron acceptor.The obtained experimental results have pointed to the absence of the effect of meturine upon the photoreaction I.Unlike N-phenyl—N′, N′-dimethylureas (CMU, DCMU) meturine has been a very weak inhibitor of photoreaction II.The authors explain the photoreaction II inhibition of chloroplasts from plants treated with herbicidal doses of meturine by conversion of N-phenyl—N-hydroxy—N′-methylurea into Hill reaction inhibitor(s). N-Phenyl—N′-methylurea can be one of such meturine metabolites.Meturine herbicidal action is accounted for by meturine transformation into Hill reaction inhibitor(s) in the plant tissues.     

甲基硫菌灵标样的制备

本文介绍了用进口甲基硫菌灵样品，采用溶剂萃取，高速离心，重结晶，高效液相色谱，红外光谱等分析方法进行系统分离与鉴定，得到其标样的方法。     

Measures of durability of resistance

ABSTRACT Conventional models for the durability of resistant cultivars focus on the dynamics of the frequency of resistance genes. This leads to a definition of the durability of resistance as the time from introduction of the cultivar to the time when the frequency of the virulence gene reaches a preset threshold. It is questionable whether this is the most appropriate way to measure durability. Here we use a simple epidemiological model to link population dynamics and population genetics to compare three measures of durability: (i) the expected time until invasion of the virulent genotype, by mutation or immigration, and subsequent establishment of a population (T(invasion)); (ii) the virulence frequency related measure of the time for the virulent genotype to take-over the pathogen population ( T(take-over)); and (iii) the additional yield, measured by the additional number of uninfected host growth days (T(additional)). Specifically, we show how the measures of durability are affected by deployment and epidemiological parameters. We use a combination of numerical solution and analytical approximation of a model for the population dynamics of avirulent and virulent genotypes of a pathogen growing in dynamically changing populations of resistant and susceptible cultivars. The three measures of durability are compared. Some consequences of the results for durable resistance in multilines and mixtures and the regional deployment of resistant cultivars are discussed.