VASCULAR INFECTION OF COTTON BY XANTHOMONAS MALVACEARUM (E. F. SMITH) DOWSON

Cotton seedlings raised under glass from seed pre-soaked in a water suspension of Xanthomonas malvacearum , and watered by sub-irrigation only, developed atypical dull green flaccid areas extending from the periphery of the cotyledons. Later symptoms that variably developed were: vascular discoloration, not necessarily continuous, in the petioles of affected cotyledons, in the hypocotyl, and in parts of the plant above the cotyledonary node; premature withering of cotyledons; dull green flaccid areas in true leaves, not necessarily the lowest, later turning brown and drying, with usually a chlorotic margin; parenchymatous attack in stems, petioles and leaves. Evidence is adduced, from the progression of symptoms and from associations between them, and from isolations of the pathogen from various parts of the plant at different stages, that the course of this type of infection is primarily vascular, progressing from the edges of cotyledons into the hypocotyl and thence upwards in vascular tissues. Thence the infection may break out at any time into parenchymatous tissues, leading to the more characteristic forms of the disease, of greater or less severity according to the susceptibility of the parenchyma at the time of its invasion. Similar symptoms have been observed in field plantings, and it is suggested that vascular infection is of greater and wider significance in the epidemiology of bacterial blight than has hitherto been commonly accepted.     

LEAF INFECTION OF COTTON BY XANTHOMONAS MALVACEARUM (E.F.SM.) DOWSON

Xanthomonas malvacearum spread more rapidly along vascular tissue than into mesophyll when inoculated to the main veins of susceptible cotton leaves. The extent of spread varied with the concentrations of inocula, tissue age and cotton variety.
Increasing concentrations of inocula accelerated the initial spread of disease.
Bacteria spread more rapidly in young leaves than in old—increasing age greatly decreased disease in the mesophyll. The initial invasion was quicker in young leaves of young plants than in young leaves of old plants.
Three types of behaviour, according to the host's reaction, distinguish Knight's resistance factors: ( a ) where X. malvacearum spread extensively along veins and into mesophyll of plants containing factors B₃ and B₅; ( b ) where it was restricted to the point of inoculation in plants containing B ₄, B₉ and combinations with B _6m; and ( c ) where it spread along veins but not appreciably into mesophyll in varieties containing B ₂ and B ₂ B ₃.
From this and four other different types of tests, factors B ₂ and B ₃ seem to increase mesophyll resistance but only B ₂ gives appreciable vascular resistance. Further, the vascular bundles in varieties with B ₂ seem to be surrounded by an additional 'barrier' which resists X. malvacearum.     

STEM INFECTION OF COTTON BY XANTHOMONAS MALVACEARUM (E. F. SM.) DOWSON

Varying the position of stem inoculation, the concentration of inoculum and the age of plant affected the reaction of cotton, Gossypium sp., to infection with Xanthomonas malvacearum (E. F. Sm.) Dowson.
The extent of stem discoloration, internal and external, and the probability of disease ocurring in leaves by bacteria moving within the plant increased ( a ) the nearer the point of stem inoculation was to the apex, and ( b ) the higher the concentration of inoculum. The leaf symptoms were not the angular spots typical of primary leaf infection. Instead, bacteria seemed to lodge in, discolour and blacken sections of leaf veins. Then tissue next to the affected veins became water-soaked and leaf sectors dependent upon these veins died and dried. These symptoms usually developed 14 to 55 days after inoculation in the expanding leaves.
The amounts of stem discoloration and the probabilities of leaf symptoms developing were less when hypocotyls of old plants were inoculated than when hypocotyls of young plants were inoculated. The probabilities of leaf symptoms developing were similar, however, when young tissues in young and old plants were inoculated.
American cotton, Gossypium hirsutum , was less affected by stem inoculation than Egyptian cotton, G. barbadense. Of the resistance factors against primary leaf infection only B_6m gave appreciable stem resistance.     

中国细长蚁属系统分类研究(膜翅目,蚁科)

在中国记载细长蚁属Tetraponera F. Smith昆虫13种,其中在云南省描述5新种,报道中国1新纪录种.编制了工蚁的分种检索表.评论了该属中国种类的分类历史.13个已知种依次是红黑细长蚁T.rufonigra(Jerdon),凹唇细长蚁T.concava sp.nov.,宾氏细长蚁T.binghami(Forel),狭唇细长蚁T.attenuata F.Smith,显赫细长蚁T.notabilis Ward,光亮细长蚁T.nitida(F.Smith),隆背细长蚁T.convexa sp.nov.,榕细长蚁T.microcarpa Wu et Wang,叉唇细长蚁T.furcata sp.nov.,尖唇细长蚁T.protensa sp.nov.,飘细长蚁T.allaborans(Walker),无缘细长蚁T.amargina sp.nov,平静细长蚁T.modesta(F.Smith).显赫细长蚁T.notabilis Ward为中国新纪录种.     

中国大陆瘤颚蚁属分类研究(膜翅目,蚁科)

记述中国大陆瘤颚蚁属Strumigenys 8种,其中1新种,江西瘤颚蚁S．jiangxiensis sp．nov．,粗瘤颚蚁S．stry—gax Bolton为中国新纪录种。提出《广西蚂蚁》和《西双版纳自然保护区蚁科昆虫生物多样性研究》中记载的4个误订种,即刘氏瘤颚蚁S．lewisi Cameron误订为粗糙瘤颚蚁S．hispida Lin et Wu,薄帘瘤颚蚁S．rallarhina Bolton误订为异形瘤颚蚁S．leptorhina Bolton,粗瘤颚蚁S．strygax Bolton误定为琴状瘤颚蚁S．1yroessa(Roger),长瘤颚蚁S．exilirhi-na误定为费氏瘤颚蚁S．feae Emery。编制了中国大陆瘤颚蚁属已知种工蚁的分类检索表。     

EVIDENCE FOR SEVERAL SIBLING BIOLOGICAL SPECIES CENTRED ON MYRMECZA PZLOSULA (F. SMITH) (HYMENOPTERA: FORMICIDAE)

Abstract
The behaviour in laboratory bioassays of male codling moth, Cydia pomonella (L.), when presented with various mixtures of ( E, E )-8, 10-dodecadienol and the 2 saturated alcohols, dodecanol and tetradeconol, shows that the presence of all 3 compounds is necessary in order to obtain a response equivalent to that elicited by the natural pheromone.     

EVIDENCE FOR SEVERAL SIBLING BIOLOGICAL SPECIES CENTRED ON MYRMECIA PILOSULA (F. SMITH) (HYMENOPTERA: FORMICIDAE)

Abstract
Chromosome numbers of 2n = 2,9,10,18,19,20,21,22,23,24,25,26,27,30,31 and 32 were found for Myrmecia pilosula (F. Smith). Karyotopic and morphological evidence indicates the presence of a M. pilosula complex with at least 3 biological species.     

芒果褐色蒂腐病菌(Phomopsis mangiferae)生物学特性研究

从广西芒果病区分离出芒果褐色蒂腐病菌 (Phomopsismangiferae) ,对其生物学特性进行的研究结果表明 ,该病菌的最适生长温度为 2 5～ 31℃ ;最适生长 pH值为 6 .0～ 6 .5 ;不同光环境对分生孢子器形成的影响较大 ,其中黑光最利于分生孢子器的形成 ;多菌灵对该病菌的室内抑制作用最强     

棉铃虫幼虫中肠类胰蛋白酶基因的克隆及在大肠杆菌中的表达

根据昆虫类胰蛋白酶序列的保守性设计了一对引物,以棉铃虫（Helicoverpa armigera)幼虫中肠总RNA反转录出cDNA第一链作为模板,利用RT－PCR,分离出了一种棉铃虫类胰蛋白酶（HaT)基因的cDNA序列。分析表明该cDNA序列的开放阅读框为696bp,编码一个由231个氨基酸残基组成的多肽,推测的氨基酸序列具有His57,Asp102,Ser192组成的电荷中继网,决定胰蛋白酶底物专一性的Asp189,底物结合部位的Gly216和Gly226残基,及其它胰蛋白酶结构上的保守区域。氨基酸序列同源性比较表明：HaT同其它鳞翅目昆虫类胰蛋白酶有较高的同源性,同源性在44％－79％之间。为研究棉铃虫类胰蛋白酶基因（hat)编码产物的活性,将其插入原核表达载体pGEX4T-3和pET23b中,并在大肠杆菌中进行了诱导表达,结果表明,GST－HaT融合蛋白在大肠杆菌中进行了特异表达,非融合形式的表达产物HaT具有胰蛋白酶催化活性。     

FURTHER OBSERVATIONS ON THE BREEDING BEHAVIOUR OF LABEO UMBRATUS (SMITH) (PISCES: CYPRINIDAE)

SUMMARY

Breeding behaviour of Labeo umbratus was observed in the Modder River, Orange Free State, and ova were collected from below the site and hatched. Fry were reared for 12 months to confirm the identification of the ova collected. The behaviour of spawning fish and the oviposition site are described.