芦荟黑斑病病原鉴定及培养特性的研究

为进一步了解芦荟黑斑病的发生规律,采用组织分离法、血球计数板法、悬滴法等对病原菌进行了形态鉴定及其培养特性的研究。结果表明,芦荟黑斑病的病原菌为倒梨形链格孢(Alternaria obpyriformisT Y Zhang)。该菌菌丝生长和分生孢子产生的温度范围为10~30℃,最适温度为25℃;在pH 3.92~10.82的范围内该菌均能生长和产孢,菌丝生长最适pH 3.92~6.83,产生分生孢子的最适pH 5.23~6.83;分生孢子萌发的温度范围为10~35℃,最适20~30℃,最适pH 3.86~9.23。分生孢子在饱和湿度或水滴中萌发快,相对湿度低于81%时不能萌发。分生孢子的致死温度为55℃,10 min。光暗交替下培养的菌丝生长最好,产孢量最多,其次是完全黑暗下,而连续光照条件下的菌丝生长缓慢且产孢量少。该菌适合在含有芦荟成分的培养基上生长和产孢,能利用多种单糖、多糖及醇类作碳源和L-亮氨酸等有机氮和硫酸铵等无机氮作氮源。     

茭白胡麻斑病菌生物学特性研究

对茭白胡麻斑病生物学特性进行了研究,结果表明：该菌菌丝生长的适宜温度10~35℃,最适温度25℃;分生孢子产生的适宜温度10~30℃,最适温度25℃;分生孢子致死温度为56℃;该菌菌丝生长和分生孢子产生的pH值3~12,最适pH值6~9,中性偏碱的条件下有利于分生孢子的形成;该菌菌丝生长最适碳源为乳糖,而产孢最适碳源为果糖;氮源酵母膏促进菌丝生长,酵母膏和氯化铵能促进产孢,牛肉膏和硝酸钾不利于产孢。     

魔芋灰霉病致病菌及其生理特性的研究

为探明魔芋灰霉病的发病规律,对其发病症状、致病菌及其生理特性进行了较系统的研究。结果表明,魔芋灰霉病菌为葡萄孢菌属(Botryotinia);其分生孢子萌发的温度范围为10~30℃,最适温度为20~25℃;在pH 4~9条件下均能萌发,最适pH为5;在各种营养液中均能萌发,在2%的蔗糖液中萌发最好,其次为2%的葡萄糖和魔芋甘露低聚糖;分生孢子的致死温度为57℃、5 min。魔芋灰霉病菌菌丝在4种培养基上均能生长,其中PDA培养基最适宜菌丝生长,最适的产孢培养基为PDA+魔芋甘露低聚糖;菌丝在5~30℃均能生长和产孢,适宜温度为20~25℃;在pH 4~9均能生长及产孢,最适pH为5。     

甘薯疮痂病菌的生物学特性和产孢方法研究

探究甘薯疮痂病菌(Elsinoe batatas)的生物学特性,筛选疮痂病菌在人工培养基上快速、大量地产生分生孢子的方法,为甘薯抗疮痂病育种提供依据。以疮痂病病原菌菌株CRI-CJ2为研究对象,采用菌丝生长速率法测定在不同培养基、p H和光照处理条件下的菌落生长直径,利用凹玻片悬滴法测定在不同温度、pH和光照处理条件下的分生孢子萌发率,比较Fries液体培养法、摇菌法和菌丝涂布法等3种方法的诱导产孢效果。结果表明,最适菌丝生长的培养基为PDA,p H 6～7,致死温度为48℃、10 min,光照对菌丝生长无显著影响,但连续光照使菌落呈鲜红色;分生孢子萌发最适pH 5,最适温度为25℃,致死温度为48℃、10 min,光照对分生孢子萌发影响不显著;采用菌丝涂布法可使疮痂病菌在培养第12天分生孢子产孢量达7.09×10⁷个/m L,分生孢子萌发率为24%,产孢量和孢子活力均高于摇菌法,采用Fries液体培养法未观察到分生孢子及产孢结构。可见,选用适宜的培养基、p H能促进菌丝体生长,菌丝涂布法具有产孢快、产孢量大的优点,是一种适合甘薯疮痂病菌分生孢子诱生的方法。     

滇西红花油茶褐斑病病原鉴定、致病性

为了给腾冲红花油茶(Camellia reticulata f. simpex Sealy)褐斑病的综合防治提供一定的理论依据,通过实地调查与室内分离、鉴定及接种试验,对腾冲红花油茶褐斑病病原菌及其致病性进行了研究。结果表明,红花油茶褐斑病病原为半知菌亚门腔孢纲黑盘孢目（科）的拟盘多毛孢属茶褐斑拟盘多毛孢Pestalotiopsis guepini。该菌种在人工针刺接种条件下均能在大棚内表现出典型症状。并将发病叶片再分离,得到同样的病原。该菌在PDA培养基上菌丝生长温度为10~30℃,最适25℃;产生分生孢子的温度为20~25℃,最适25℃;分生孢子萌发的温度为15~30℃,最适28℃。该病菌在pH4~8条件下均能生长和产孢,产生分生孢子最适pH5~6,分生孢子萌发和菌丝生长最适pH5。该菌对生长势弱或有伤口的植株有很强的致病性,并为红花油茶褐斑病病原学、发病规律及防治技术的系统研究奠定了基础。     

杨梅叶枯病菌（Phomopsis myricina）生物学特性研究

杨梅叶枯病菌（Phomopsis myricina）生物学特性研究结果表明：该菌菌丝生长与分生孢子器形成最佳培养基为PSA+1‰酵母膏和PDA+1‰酵母膏。病菌能有效地利用多种碳源和氮源，但谷氨酸和精氨酸对病菌生长发育有抑制作用。菌丝生长和分生孢子器形成最适温度为20~25℃；最适pH值分别为6~8和7~9。紫外光处理有利于产孢。分生孢子萌发最适温度为20~30℃；最适pH值7~9；在相对湿度98%以上和水滴中孢子萌发率最高；不同营养对孢子萌发无显著影响。     

齿瓣石斛病原链格孢菌生物学特性研究

对齿瓣石斛(Dendrobium devonianum Paxt.)黑斑病病原物链格孢菌(Alternaria tenuis Nees)进行分离并对其生物学特性进行研究.用常规组织分离法从齿瓣石斛叶片中分离黑斑病病原物链格孢菌,以PSA为基本培养基,研究培养基pH值、附加不同碳源和氮源、温度、光照等培养条件对链格孢菌菌丝生长及产孢的影响.齿瓣石斛链格孢菌菌丝最适宜生长的温度25℃,20℃最宜产孢;最适宜的pH值为5～6;光照对菌丝生长影响不显著,产孢量以光暗交替下培养最多;在PSA培养基上加入淀粉或硝酸铵对菌丝生长最好,产孢则以葡萄糖较好,在其他碳源或氮源的培养基上极少产孢.齿瓣石斛链格孢菌适宜在PSA培养基pH值为5～6,附加一定葡萄糖和硝酸铵,25℃和光暗交替下生长.     

棉花红腐病病原菌生物学特性的研究

棉花红腐病菌菌丝生长的最适宜培养基为 PSA培养基,最适温度范围 20~25℃, 最适pH值7.0~9.0,光照对该菌的生长几乎没有影响,而紫外线对该菌的生长有一定的抑制作用。病菌对碳源的利用以蔗糖和麦芽糖最佳,氮源的利用以硫酸铵和氯化铵最佳。产孢量在温度25℃、pH 7.0、紫外线照射80 min、查彼培养基上达到最大。分生孢子萌发的最适温度为20~25℃、最适pH 9.0、湿度86%以上。总之,该菌属于中高温、高湿、中性偏碱性菌。     

玉米叶斑病菌麦根腐平脐蠕孢的生物学特性及其对杀菌剂的敏感性

麦根腐平脐蠕孢是引起玉米叶斑病的一种病原菌。明确了该病原菌在不同温度、pH及碳/氮源条件下的菌丝生长、产孢量及孢子萌发等生物学特性,并评价该病原菌对8种常用杀菌剂的敏感性。结果表明,温度为28℃时菌丝生长最快,达到73. 00 mm,并且孢子萌发率最高,为96. 91%;产孢的最佳温度为25℃,孢子量为15. 13×10~3/cm~2。在pH值7和8的培养基上菌丝生长最快,分别为65. 25,65. 13 mm,孢子萌发率分别为88. 75%,85. 00%;在pH值7的培养基上产孢量最高,为48. 44×10~3/cm~2。在以淀粉和蔗糖为碳源的培养基上菌丝生长量分别为53. 00,50. 17 mm;在以半乳糖为碳源的培养基上产孢量最高,为1. 93×10~4/cm~2,其次为淀粉培养基,产孢量为0. 42×10~4/cm~2;在以淀粉、半乳糖和蔗糖为碳源的培养基上孢子萌发率分别为76. 03%,74. 52%,72. 26%。在以硝酸钠为氮源的培养基上菌丝生长最快,为36. 44 mm;在以脯氨酸为氮源的培养基上产孢量最高,为5. 59×10~3/cm~2;在以脯氨酸和硝酸钠为氮源的培养基上孢子萌发率分别为49. 38%,45. 00%。对供试杀菌剂敏感性测定结果表明,戊唑醇和咯菌腈对菌丝生长抑制活性最高,EC_(50)均为0. 07 mg/L,咯菌腈对孢子萌发的抑制活性最高,EC_(50)为2. 80 mg/L。结果将为了解玉米麦根腐平脐蠕孢叶斑病的发生流行规律并制定有效防治措施提供理论依据。     

黄瓜新炭疽病原的鉴定及生物学特性初探

明确引起黄瓜炭疽病的病原,旨在为该病的有效防治提供理论依据。通过形态学方法、柯赫氏法则验证,基于ITS、ACT和GDPH序列分析鉴定病原菌,并对该菌的生物学特性进行研究。结果表明,该菌回接黄瓜后的症状与田间症状一致。在PDA培养基上菌落为黑色,气生菌丝稀疏、灰白色;分生孢子长柱形,透明无隔;分生孢子盘着生黑色刚毛;孢子附着胞浅褐色,卵圆形,个别双生;菌丝附着胞深褐色,不规则形、浅裂或深裂。结合病原菌三基因联合建树的分析结果,可将其鉴定为Colletotrichum brevisporum。最适菌丝生长和产孢的温度25℃、pH 8,在PDA培养基上菌丝延伸最快,OA培养基上产孢最多,碳源中葡萄糖利于菌丝生长,可溶性淀粉和乳糖利于产孢,氮源中蛋白胨和酵母浸粉最适合菌丝生长,且后者产孢最多,致死温度为49℃。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Evolution under domestication involving disturbance of genic balance

Summary An hypothesis is developed that the rapid change from wild plants into domesticated crops principally involves the selection of alleles with non-functional gene products which leads to reduced control of the highly integrated metabolism and morphogenesis previously accumulated by lengthy natural selection. Such disturbance of the genome produces altered physiological and morphological development which, although deleterious in nature, serves mankind better and has been selected.     

Genetic variation for disease and nematode resistances and forage quality in perennial diploid and tetraploid lucerne populations (Medicago sativa L.)

Summary Twenty-five lucerne populations of the Medicago sativa complex, which were either diploid or tetraploid and wild or cultivated, were analysed for their resistance to four different fungal diseases and to stem nematode. Forage quality, including stem digestibility and saponin content, was also tested.Populations varied in susceptibility to the diseases caused by Colletotrichum trifolii, Verticillium albo-atrum, Sclerotinia trifoliorum and Pseudopezizza medicaginis, and to the nematode Ditylenchus dipsaci. Except for Sclerotinia rot, sativa and falcata subspecies differed in susceptibility, but this grouping of populations did not account for the full range of variation among them. However, the resistance to P. medicaginis was much lower in the sativa than in the falcata populations.Populations also varied significantly in stem fiber content and digestibility. Stem digestibility was negatively correlated to forage yield. Wild sativa and falcata populations had lower fiber content and higher digestibility than cultivated sativa populations. The medicagenic acid was the sapogenin responsible for the anti-nutritional effect of the lucerne measured by the yellow mealworm larvae Tenebrio molitor. The medicagenic acid content was lowest for the pure sativa populations, highest for the pure falcata populations, and intermediate for the French sativa varieties that have some traits originating from falcata germplasm. Some populations could be used in breeding programs to improve disease and nematode resistance, and forage quality.     

Review of Effects of Active Components of Gastrodiae Rhizoma on Central Nervous System

In order to explore the pharmacological effects of active components of Gastrodiae Rhizoma on the central nervous system,through consulting related literatures,...     

Effects of Pb on Rhizosphere Soil Enzyme Activity and Chemical Constituents of Achyranthes bidentata Blume

[Objectives]The purpose of this study was to investigate the effects of Pb on rhizosphere soil enzyme activity and chemical constituents of Achyranthes bidentat...     

不同P-Zn配比对小麦幼苗微量元素营养的影响

采用了螯合-缓冲营养液培养方法对小麦进行了苗期培养试验,在3个P水平(0,0.6,3.0 mmol/L)和3个Zn水平(0,3,30 μmol/L)的完全组合下对小麦苗期生长及Zn、Fe、Cu、Mn营养进行了研究,旨在为小麦微肥施用提供理论依据.结果表明,P、Zn的正常供应促进了小麦生长,二者的缺乏与过量均会抑制小麦发育,且这种影响在冠部表现得更为明显.在小麦苗期,Zn与Cu的吸收存在明显的拮抗作用,但供Zn则促进了Zn和Cu的转运,而Mn转运则受到了抑制;过量供Zn时,大量Zn被转运到冠部,同时明显抑制了(Fe+Cu+Mn)的吸收总量;P的供应显著地抑制了Fe的吸收,但P的供应提高了Zn、Cu、Mn的转运率;P、Zn在对Zn与Fe、Cu、Mn间吸收竞争的影响中,Zn本身的影响要比P的影响更为明显,供Zn明显促进了小麦幼苗对Zn的吸收;在小麦幼苗冠部,Zn与Fe的竞争中,供P利于Zn的吸收,缺P则利于Fe的吸收;而Zn与Cu以及Zn与Mn间的竞争中,缺磷时利于Zn的吸收,供磷后则利于Cu和Mn的吸收.总之,小麦幼苗Zn、Fe、Cu、Mn营养中,P、Zn的不同配比会不同程度地改变Zn与Fe、Cu、Mn的协同或拮抗效应.     

Isozyme variation between diploid and tetraploid cytotypes of Glycine tabacina (Labill.) Benth.

Summary Glycine tabacina (Labill.) Benth. is a wild perennial species related to the cultivated soybean, G. max (L.) Merr. It is composed of diploid (2n=40) and tetraploid (2n=80) cytotypes. Currently, to differentiate the cytotypes, plants are grown out in the greenhouse and chromosome counts made on pollen mother cells. It is a laborious and time consuming process. The objective of this study was to determine whether electrophoretic techniques could be utilized to separate the cytotypes. Electrophoretic examination of seven isozyme systems from seed of 67 G. tabacina accessions revealed banding patterns that could be used to differentiate between diploid and tetraploid cytotypes in the species. Among the tetraploid accessions, the number of bands observed were always greater than the diploids. Some tetraploid banding patterns consisted of bands similar to the diploid tabacina and/or additional bands previously identified in other Glycine species. The patterns of isozyme multiplicity and variation in the tetraploid tabacinas suggests more than one mode of origin for the tetraploids.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.