Short Pedicels Research Articles

Effect of calcium on cyclamen pedicel elongation

AbstractA greenhouse experiment was conducted to study the effect of calcium (Ca) supply on pedicel growth of Cyclamen persicum “Metis” during flower development. When flower buds started to develop, four foliar spray Ca treatments were applied, including Ca0 (no added Ca as control), Ca(NO3)2, CaEDTA, and CaEDTA+H3BO3. Calcium spray treatments significantly reduced the number of short pedicels. There were 62% of the flowers with short pedicels (i.e., flower height lower than the foliar height) in the control treatment (Ca0). Short pedicels accounted for 23%, 12%, and 10% in the Ca(NO3)2‐, CaEDTA‐, and CaEDTA+H3BO3‐treated plants, respectively. CaEDTA was a more effective Ca source than Ca(NO3)2 for improving cyclamen pedicel elongation and increasing flower numbers. Additional boron (B) supply may have enhanced Ca translocation within the plant. Transmission electron microscopy (TEM) indicated that pedicel‐cell structure was severely damaged in the control plants. Pedicel‐cell damage was greatly alleviated in plants treated with Ca(NO3)2. No symptoms of cell damage were found in the CaEDTA‐ and CaEDTA+H3BO3‐treated plants. Energy‐dispersive X‐ray spectrometer (EDX) analysis confirmed that CaEDTA+H3BO3 and CaEDTA had increased the Ca : O ratios. Therefore, Ca localization in the pedicel cell had a great influence on the pedicel height of cyclamen, and Ca concentration could be a good indicator for undisturbed cyclamen flower development.

First Report of Bud Rot of Canary Island Date Palm Caused by Phytophthora palmivora in Italy.

Canary Island date palm (Phoenix canariensis hort. ex Chabaud) is planted as an ornamental in Mediterranean climatic regions of the world. From 2004 to 2006, withering of the spear leaf was observed on screenhouse-grown potted plants of this palm in Sicily (Italy). The first symptom was a dark brown rot that extended from the petiole base of the spear to the adjacent youngest leaves and killed the bud. Dissection of plants revealed a foul-smelling internal rot. After the bud died, external older leaves remained green for months. As much as 10% of plants in a single nursery were affected. A Phytophthora species was consistently isolated from symptomatic plants on BNPRAH selective medium (4). Single zoospore isolates were obtained from the colonies. The species isolated was identified as Phytophthora palmivora (E. J. Butler) E. J. Butler on the basis of morphological and cultural characteristics (3). On V8 juice agar, the isolates produced elliptical to ovoid, papillate sporangia (33 to 77 × 22 to 38 μm) with a mean length/breadth ratio of 1.8. Sporangia were caducous with a short pedicel (mean pedicel length = 5 μm) and had a conspicuous basal plug. All isolates were heterothallic and produced amphigynous antheridia, oogonia, and oospores when paired with reference isolates of P. nicotianae and P. palmivora of the A2 mating type. The oogonium wall was smooth. Identification was confirmed by electrophoresis of mycelial proteins in polyacrylamide slab gels (1). The electrophoretic patterns of total mycelial proteins and four isozymes (alkaline phosphatase, esterase, glucose-6-phosphate dehydrogenase, and malate dehydrogenase of the isolates) from Phoenix canariensis were identical to those of P. palmivora reference isolates, including four Italian ones, two from pittosporum and olive, respectively, and two (IMI 390579 and 390580) from Grevillea spp. Phoenix canariensis isolates were clearly distinct from those of other heterothallic papillate species including P. capsici, P. citrophthora, P. katsurae, P. nicotianae, and P. tropicalis. Pathogenicity of one isolate from Phoenix canariensis (IMI 395345) was tested on 10 2-year-old potted Canary Island date palm plants. An aqueous 105 zoospores per ml suspension (200 μl) was pipetted onto unwounded petiole bases of the three youngest central leaves of each plant. Sterile water was pipetted onto 10 control plants. All plants were incubated in 100% humidity at 24°C for 48 h and maintained in a greenhouse at 20 to 28°C. Within 3 weeks after inoculation, inoculated plants developed symptoms identical to those observed on plants with natural infections. Control plants remained healthy. P. palmivora was reisolated from symptomatic plants. Phytophthora bud rot is a common palm disease worldwide and Phoenix canariensis is reported as a host (2). To our knowledge, this is the first report of Phytophthora bud rot on Phoenix canariensis in Italy.

Meristem maintenance and compound-leaf patterning utilize common genetic mechanisms in tomato

Balancing shoot apical meristem (SAM) maintenance and organ formation from its flanks is essential for proper plant growth and development and for the flexibility of organ production in response to internal and external cues. Leaves are formed at the SAM flanks and display a wide variability in size and form. Tomato (Solanum lycopersicum) leaves are compound with lobed margins. We exploited 18 recessive tomato mutants, representing four distinct phenotypic classes and six complementation groups, to track the genetic mechanisms involved in meristem function and compound-leaf patterning in tomato. In goblet (gob) mutants, the SAM terminates following cotyledon production, but occasionally partially recovers and produces simple leaves. expelled shoot (exp) meristems terminate after the production of several leaves, and these leaves show a reduced level of compoundness. short pedicel (spd) mutants are bushy, with impaired meristem structure, compact inflorescences, short pedicels and less compound leaves. In multi drop (mud) mutants, the leaves are more compound and the SAM tends to divide into two active meristems after the production of a few leaves. The range of leaf-compoundness phenotypes observed in these mutants suggests that compound-leaf patterning involves an array of genetic factors, which act successively to elaborate leaf shape. Furthermore, the results indicate that similar mechanisms underlie SAM activity and compound-leaf patterning in tomato.

First Report of Wilt and Stem Canker of Poinsettia (Euphorbia pulcherrima) Caused by Phytophthora nicotianae in Puerto Rico.

Poinsettias are grown extensively in greenhouses in Puerto Rico, a five million dollar industry during the winter season of 2005. More than 2,000 'Freedom' plants from an ornamental nursery near Aibonito exhibited severe wilt and dieback symptoms. The disease was found in 5 of 12 surveyed greenhouses where severity ranged from 50 to 100% and occurred regardless of the use of metalaxyl and mefenoxam. Symptoms during the growth phase included stunted plants, thin stems, chlorotic leaves, and brown roots. During flower bract development, symptoms consisted of leaf wilting often in sectors, stem canker, and purple-to-black lesions that extended from the stem to the petioles followed by soft rot. Isolations from symptomatic stem and root tissue were made on corn meal agar (CMA) (17 g/liter) amended with pimaricin (10 mg/liter), ampicillin (250 mg/liter), rifampicin (10 mg/liter), pentachloronitrobenzene (100 mg/liter), and hymexazol (50 mg/liter) (PARPH) (1). Pure cultures were obtained by hyphal-tip transfers onto CMA-PARPH. Colonies grown on acidified potato dextrose agar (APDA) at 25°C were arachnoid with abundant aerial mycelium and sporangia. Sporangia formed singly or in a loose sympodium on long sporangiophores and were papillate, mostly persistent, or caducous with short pedicel. The shape of sporangia varied from ellipsoidal to elongated ovoid, with a length/breath ratio of 16.5 × 14.2 μm. Large, spherical, terminal, and intercalary chlamydospores readily formed in APDA and PARPH. The isolate was identified as Phytophthora nicotianae on the basis of morphological and molecular characteristics. Molecular identification by sequence analysis of the internal transcribed spacer rDNA region confirmed the identity of the isolate P210.1 as P. nicotianae (GenBank Accession No. DQ485412). Pathogenicity tests were conducted with isolates P210.1 and IG grown on APDA for 7 days at 24°C. Isolates were then covered with sterile water for 48 h to induce sporangia and zoospore production at 24°C and continuous light. A suspension of 10 ml of approximately 120 sporangia ml-1 were added to pots containing 2.2 kg of a 1:1 mixture of field soil and soilless media (Promix) composed of peat moss vermiculite and perlite. One healthy poinsettia rooted stem and one 2-month-old plant were transplanted individually into the inoculated soil and pots were flooded with sterile water for 24 h. A noninoculated control was included, each isolate and control were replicated five times. First symptoms (7 to 10 days after inoculation) included brown, limited root growth and lower stem discoloration. Plants (30- to 45-day-old) show a decline in vigor and rapid death of branches that are similar symptoms to those observed on infected poinsettias in commercial greenhouses. P. nicotianae was reisolated from infected root, crown, and stem tissue on PARPH media. A strict sanitation program was recommended to prevent recontamination. To our knowledge, this is the first report of P. nicotianae on poinsettia in Puerto Rico. Reference: D. J. Mitchell and M. E. Kannwischer-Mitchel, Phytophthora. Page:31 in: Methods for Research on Soilborne Phytopathogenic Fungi. L. L. Singleton et al., eds. The American Phytopathological Society, St. Paul, MN, 1993.

Phytophthora palmivora, agente da podridão de raiz e frutos de mamoeiro no Estado de Alagoas

O mamoeiro (Carica papaya) é uma das mais importantes fruteiras tropicais, e seus frutos contribuem com uma produção de 1,65 milhão de toneladas por ano para o Brasil. Um isolado de Phytophthora sp. obtido de frutos de mamoeiro da cultivar Havaí, em Alagoas, foi caracterizado morfologicamente e sua patogenicidade foi confirmada em frutos e mudas deste hospedeiro. Em meio suco V-8, os esporangióforos apresentaram-se delgados, simples ou pouco ramificados, enquanto os esporângios se apresentaram ovóides a elipsóides, proeminentemente papilados e um pedicelo curto na porção basal, medindo em média 37,68 x 27,52 mm. Através das características apresentadas pelo isolado e os sintomas induzidos, o agente causal foi identificado como Phytophthora palmivora. Apesar de essa doença já ocorrer em outros estados, como Bahia, Espírito Santo, São Paulo, Pernambuco e Pará, este é o primeiro relato de Phytophthora palmivora em mamoeiro no Estado de Alagoas.

Lavender Cotton Root Rot: A New Host of Phytophthora tentaculata Found in Spain.

Lavender cotton, Santolina chamaecyparissus, is an evergreen shrub growing primarily in dry, calcareous habitats and is grown in rock gardens and mixed borders mainly for its ornamental and aromatic foliage. During 2004, several commercial nurseries in Valencia Province (eastern Spain) reported high mortality of lavender cotton. The foliage of the diseased plants turned brown, wilted, and died. A Phytophthora sp. was isolated consistently from the soil and roots of infected plants using apple baits and the selective medium PARBH (1), respectively. Four pure cultures (PS-31, PS-32, PS-33, and PS-34) were established from hyphal tips and characterized. Colony morphology on potato dextrose agar (PDA) at 24°C was stoloniferous (short stubby branches) with a growth rate of 2.2 mm per day. Sporangia, chlamydospores, and oospores were produced on V8 agar. The sporangia were ovoid to obpyriform, 27.5 to 64.8 (48.3) × 25 to 52.5 (37.5) μm, length/breadth ratio of 1.3:1, and papillate, from which 20% were caducous with a short pedicel (<5 μm). Hyphal swellings and chlamydospores (22 to 38 μm in diameter) were present. Isolates were homothallic, oogonia were globose, mostly terminal 27.5 to 40 (36.2) μm in diameter, 88% of the antheridia were paragynous, monoclinous, or diclinous, and occasionally with two paragynous antheridia per oogonium. Amphigynous antheridia (12%) were also observed. Oospores were aplerotic, 25 to 35 (32.3) μm in diameter, and thin walled. These characteristics and measurements conformed to the description of P. tentaculata described by Kröber and Marwitz (2). Sequencing the internal transcribed spacer region of Santolina isolates PS-32 and PS-34 and comparison of these sequences with other sequences available in GenBank revealed that they were identical to P. tentaculata (AF266775). Pathogenicity tests used 10 4-to-5-month-old potted lavender cotton and two methods. In the first method, inoculum was prepared on a media of 200 g of oats and 120 ml of V8 juice to 1 liter of distilled water. The medium was inoculated with P. tentaculata grown on PDA and incubated in the dark at 20°C for 4 weeks. Inoculum was buried into the compost mixture around the roots at a rate of 3% (w/v). The second method applied a zoospore drench of 50 ml per plant (1 × 104 zoospores per ml) obtained by inducing zoospores in sterile soil extract from cultures of V8 juice agar. The control plants were inoculated with sterile media and sterile distilled water. The following day, the pots were flooded for 2 days, plants were maintained in a glasshouse at 24 ± 5°C, and watered twice a week. All plants inoculated with the first method had wilted foliage and died within 2 months after inoculation, while plants inoculated with zoospores died after 3 months. P. tentaculata was reisolated and the test was repeated twice. The control plants did not show any symptoms of the disease. P. tentaculata was first reported causing root and stalk rot on Chrysanthemum frutescens hybrids, C. leucanthemum, Delphinium ajacis, and Verbena hybrids in Germany (2). It has also been reported on Verbena hybrids in Spain (3). To our knowledge, this is the first report of P. tentaculata causing root rot on lavender cotton.

Ulmus leaves and fruits from the Early–Middle Eocene of northwestern North America: systematics and implications for character evolution within Ulmaceae

Leaves and fruits of Ulmus from the Early–Middle Eocene of British Columbia and Washington are assigned to two species. Ulmus okanaganensis sp.nov. is based on leaves attached to flowering and fruiting twigs and isolated leaves and fruits. Leaves display a polymorphism ranging from large leaves with compound teeth with a blunt apex to small ones with simple teeth resembling those of Zelkova. In extant Ulmus, sucker-shoot leaves, elongation-shoot leaves, and leaves on short annual branches often display a very similar polymorphism. In the fossil, flowers are arranged in fascicles having short pedicels. Fascicles are formed in the axils of leaves of current-year shoots and appear together with the leaves. This is uncommon in modern species of Ulmus, where leaves appear either in spring on previous-year shoots or in autumn in the axils of leaves of current-year shoots. Fruits of U. okanaganensis are samaras with extremely reduced or absent wings. Unwinged fruits of modern Ulmus are typically ciliate along the margin of the endocarp and the persistent styles but only a single fruit of U. okanaganensis has been found preserving hairs. The small, shallowly lobed perianth is situated below the endocarp. A second type of foliage is assigned to Ulmus chuchuanus (Berry) LaMotte. This foliage is wider than that of U. okanaganensis and has more densely spaced secondary veins. It also has characteristic compound teeth with primary and subsidiary teeth displaying conspicuously different orientations. Leaves of U. chuchuanus co-occur with a second type of fruit but have not been found in attachment. These fruits are larger than in U. okanaganensis, with a narrow wing, persistent styles, and a large and wide persistent perianth that tapers abruptly into the perianth tube. A cladistic analysis suggests that U. okanaganensis is nested within the subgenus Ulmus, which is a paraphyletic grade basal to the subgenus Oreoptelea. Ulmus chuchuanus foliage shows affinities to the subgenus Ulmus, while the associated fruits display affinities to the subgenus Oreoptelea.

Crown Rot of Abies balsamea var. phanerolepis Caused by Phytophthora cactorum in Virginia

In early July 2004, a severe crown rot of Canaan fir (Abies balsamea var. phanerolepis Fern.) was reported to the Virginia Cooperative Extension, Frederick County Office, and subsequently to the Virginia Tech Disease Clinic in Virginia Beach. One thousand five-year-old Canaan fir transplants (approximately 11 mm in caliper and 31 cm high) had been purchased from a tree nursery in Oregon and planted in the field in Frederick County, VA, in April of 2004. The field site had not been cultivated for 4 years after an apple orchard had been removed in 2000. By mid-May, needle browning had become serious, affecting the lower crown first. By August, transplants had suffered 40% mortality. Basal stems of affected plants were obviously discolored. Root and basal stem samples from several infected plants were then cultured on PARP-V8 agar on three different dates. Phytophthora sp. isolates were recovered from all stem samples but none from the roots. These isolates produced a large number of papillate sporangia that were caducous with short pedicels. Abundant oogonia with paragynous antheridia formed oospores directly on isolation plates within 7 days. The isolates were keyed as P. cactorum (2). This identification was confirmed using a single-strand-conformation polymorphism analysis of ribosomal DNA internal transcribed spacer (ITS)-1 (4). It appears that the source of inoculum was P. cactorum associated with the previous apple crop, since Canaan fir from the same transplant lot planted in a nearby field without a history of apples remained healthy. P. cactorum has been reported to cause root rot of noble fir (A. procera Rhedo), Pacific silver fir (A. amabilis (Dougl.) Forbes), and Shasta red fir (A. magnifica var. shastensis Lemm.) in the Pacific Northwest (3). It has also caused crown rot of Fraser fir (A. fraseri (Pursh) Poir.), noble fir, white fir (A. concolor (Gord. & Glend.) Lindl.), and balsam fir (A. balsamea (L.) Mill.) in Michigan (1). To our knowledge, this is the first report of P. cactorum attacking Canaan fir. Canaan fir currently is a recommended Christmas tree species for areas where Fraser fir does not do well due to root rot caused by Phytophthora cinnamomi. This study suggests that such a recommendation must be used with caution. Growing Canaan fir trees in P. cactorum-infested soil could result in devastating crop losses as reported in this note.

First report of Phytophthora tentaculata on Verbena sp. in Spain

The oomycete Phytophthora tentaculata causes root and stalk rot of Chrysanthemum spp., Delphinium ajacis and Verbena spp. in nurseries in the Netherlands and Germany (Krober & Marwitz, 1993). In June 2001, P. tentaculata was isolated from a young potted Verbena hybrid, showing a collar and stalk rot, in a nursery in Majorca (Balearic Islands, Spain). It was initially recovered by plating -10 mm pieces of necrotic tissue from the leading lesion on to a phytophthora selective medium, P 5 ARP (Erwin & Ribeiro, 1996). A pure culture (isolate CBS 115458) was obtained by transferring aseptically a hyphal tip onto corn meal agar (CMA) and was first identified from morphological characters. The colony surface texture was uniform and formed sparse, loosely branched mycelium on carrot piece agar (CPA: 50 g carrot pieces and 20 g agar per 1000 mL distilled water) and CMA. The radial growth rate was 2-3 mm day -1 at 20°C on CMA. Sporangia did not appear on either agar media but formed readily in soil extract (50 g soil from a holm oak forest suspended in 1 L ionized water for 24 h at 20°C and then filtered and autoclaved). The sporangia were ovoid to globose, 27-52 (36.9) x 17-31 (24.6) μm, length:breadth ratio 1.4, papillate with a narrow exit pore, and some were caducous with a short pedicel (< 5 μm). Hyphal swellings were present in water. Chlamydospores were only seen on CMA after 2 weeks. Oogonia, readily produced on CPA in pure culture, were globose, mostly terminal or a few lateral, and ranged from 17 to 41 (34.0) μm in diameter. Single paragynous, monoclinous or diclinous, usually long-stalked antheridia were club-shaped or spherical, 9-16 (12.7) μm in diameter and many had appendages. Occasionally two paragynous antheridia per oogonium, as well as some amphigynous antheridia, were observed. Oospores were aplerotic 16-33 (28.4) μm in diameter and thin-walled. To further confirm its identity, isozyme analysis based on malate dehydrogenase (EC 1.1.1.37) and malic enzymes (EC 1.1.1.40) was performed. Isozyme profiles fitted exactly those of three P. tentaculata strains: two strains ex-Chrysanthemum (including CBS 552.96 para-type) and one strain ex-Verbena; and differing from those of all other papillate species (Oudemans & Coffey, 1991a,b). Pathogenicity was assessed by flooding three potted Verbena plants with a 10 4 mL -1 zoospore suspension for 48 h at 20-22°C. As controls, two potted Verbena plants were flooded with ionized water. Controls remained healthy 15 days after inoculation. All three inoculated Verbena plants exhibited collar rot after 15 days, from which the pathogen was reisolated using PARP medium, thus confirming Koch's postulates. This is the first report of P. tentaculata in Spain.

Treatment of lower lumbar fracture with the USS pedicel screw system

目的 报告后路短节段USS椎弓根螺钉治疗L3-5骨折的临床效果.方法1992～2004年,共救治下腰椎骨折57例,其中21例采用USS椎弓根螺钉系统固定.L3骨折12例,L4骨折8例,L5骨折1例.所用椎弓根螺钉系统均为AO-USS创伤系统.术前、术后分别测量病变椎体高度、病变节段前凸角;CT片测量椎管占位率;以Frankel评分系统评价神经功能,以Charles等人的标准评价临床效果.结果本组手术时间90～150min,平均120min;出血量100～600mL,平均350mL;术前Frankel评分3.7分,术后4.5分;术前椎节高度为正常椎体的30%～60%,术后恢复至70%～100%,平均87%,术前腰椎前凸角35.2°±8.3°,术后38.3°±10.2°.患者离床下地时间3d～2周,恢复工作时间3～6周,随访3～30个月,平均15个月.结果优9例,良9例,可2例,差1例.结论采用USS短节段椎弓根螺钉固定治疗下腰椎骨折,具有有效恢复椎节高度、腰椎前凸及椎管容积,有效防止后期出现腰痛及椎管狭窄症状,可早日下地活动及重返工作岗位等优点。

First Report of Blight on Ipomoea purpurea Caused by Phytophthora ipomoeae.

Several wild species of Ipomoea grow in the central highlands of Mexico. During the summer of 1999, in Metepec, Mexico, blighted leaves and petioles of Ipomoea purpurea were collected from diseased plants and placed in a moist chamber to induce sporulation. Sporangia that formed on the lesions were transferred with a piece of agar to selective rye agar medium (2). Phytophthora ipomoeae was consistently isolated. Species identification was based on sporangial and gametangial characteristics of five cultures grown on rye agar. Sporangia were mainly ellipsoid but occasionally ovoid, semipapillated, and deciduous with a short pedicel. All isolates were homothallic with smooth-walled and aplerotic oospores. Genotypic analysis for the allozymes Peptidase (Pep) and Glucose-6-phosphate isomerase (Gpi) indicated that all five isolates belonged to one genotype with alleles 78/78 (Pep) and 108/108 (Gpi). Morphological characteristics and the allozyme genotype correspond to the new, recently described species P. ipomoeae Flier & Grünwald (1) isolated from I. orizabensis (Pelletan) Ledeb. ex Steud. (I. tyrianthina) Lindl. and I. longepedunculata (Mart. & Gal.) Hemsl. Pathogenicity tests were carried out with leaves from greenhouse-grown I. purpurea plants. Detached leaves were inoculated with a suspension of 103 sporangia per ml and kept in a moist chamber at room temperature (17 ± 3°C). Lesions were observed between 7 and 15 days after inoculation and were characteristic of those observed in the field. The pathogen was reisolated from inoculated symptomatic tissue. To our knowledge, this is the first report of blight on I. purpurea caused by P. ipomoeae.

First Report of Downy Mildew Caused by Plasmopara obducens on Impatiens in California.

During February 2004, diseased double impatiens (Impatiens walleriana) plants were received from a commercial grower in southern California. The upper surfaces of symptomatic leaves were pale yellow with no distinct lesions. Diseased leaves later wilted, and severely affected leaves abscised from the stem. At the nursery, only double impatiens plants in the Fiesta series were infected, and some cultivars were more heavily infected than others. Disease incidence in cv. Sparkler Hot pink was nearly 100%. The interior of infected leaves was colonized by coenocytic mycelium. A conspicuous white growth was observed only on the underside of leaves. Sporangiophores were hyaline, thin walled, emergent from stomata, and had slightly swollen bases. Sporangiophore branching was distinctly monopodial. Smaller sporangiophore branches were arranged at right angles to the supporting branches, and tips of branches measured 8 to 14 μm long. Sporangia were ovoid and hyaline with a single pore on the distal ends. Distal ends of sporangia were predominantly flat but occasionally had a slight papilla. Short pedicels were present on the attached ends. Sporangia measured 19.4 to 22.2 (-25.0) μm × 13.9 to 16.7 (-19.4) μm. Oospores were not observed in leaf tissue. On the basis of symptoms and morphology of the organism, the pathogen was identified as Plasmopara obducens J. Schröt. Pathogenicity tests were done on double type cvs. Fiesta, Tioga Red, and Tioga Cherry Red and on single type cvs. Cajun Watermelon and Accent Lilac. Plants were spray inoculated with sporangiospore suspensions (1 × 104 sporangiospores per milliliter), incubated for 24 h in a dew chamber (18 to 20°C), and then maintained in a greenhouse (22 to 24°C). Symptoms and signs of downy mildew developed after 12 days only on inoculated cv. Fiesta plants, and the pathogen morphology matched that of the originally observed pathogen. Nontreated control plants did not develop downy mildew. To our knowledge, this is the first report of downy mildew on impatiens in California. P. obducens is one of two causal agents of downy mildew of impatiens (2,4). The other pathogen, Bremiella sphaerosperma, has dichotomous sporangiophore branching and causes lesions with well-defined margins (2,4). In the United States, the disease has been recorded in the eastern and northeastern states and in Indiana, Minnesota, Mississippi, Montana, and Wisconsin (3). In Canada, the disease has been recorded in Manitoba and Quebec (1).

First report of ramorum bud and leaf blight (Phytophthora ramorum) on Syringa vulgaris in the UK

The recently described pathogen Phytophthora ramorum (Werres et al., 2001) causes tree mortality (Rizzo et al., 2002), dieback and leaf blight on various ornamentals and understory plants (Inman et al., 2003; Lane et al., 2003). Due to the potential threat to European flora from P. ramorum, EC emergency legislation was introduced in November 2002. During March 2003, a Syringa vulgaris plant originating from a nursery in Scotland was examined by SASA. The leaves had yet to develop, but the terminal bud and some axillary buds were blackened and dead. A Phytophthora sp. morphologically typical for P. ramorum was isolated (Werres et al., 2001). The culture was slow-growing with weakly coralloid mycelium. Sporangia were sympodial, semipapillate, deciduous with a short (< 5 µm) pedicel (40–80 µm × 20–32 µm). Chlamydospores (25–72 µm) were also present. The culture tested positive for P. ramorum by TaqMan® PCR (K. J. D. Hughes, unpublished data). Subsequently, two separate samples of S. vulgaris were received at CSL during June 2003, both nursery-grown container plants from separate sites in England. Each plant had extensive greyish-brown, diffuse, water-soaked leaf lesions. Isolations once again conformed to P. ramorum and were confirmed by TaqMan® PCR. Pathogenicity was confirmed by inoculating healthy, unwounded detached leaves of S. vulgaris with a 9 mm plug from the edge of the original lilac isolate. After 1 week's incubation (18°C in a damp chamber), typical lesions were seen. Phytophthora ramorum was re-isolated, thereby completing Koch's postulates. No symptoms were observed on control leaves. Subsequent tests on whole lilac plants produced identical leaf lesions. Interestingly, profuse sporangia were produced from affected areas and the leaves abscised within a few days of infection. Following confirmatory diagnosis, statutory plant health action was taken to eradicate the disease. This is the first ever report of P. ramorum affecting S. vulgaris.

A new Mesozoic Ginkgo from western Liaoning, China and its evolutionary significance

Well-preserved Ginkgo ovulate organs and associated leaves are described from the fossil-bearing Yixian Formation of the Late Jurassic or Early Cretaceous in Liaoning Province, China. The ovulate organs bear a cluster of (up to 6) ovules at the apex of peduncle. The ovules are seated each in a cup-shaped collar, terminating a short pedicel in the small juvenile organ, but attached directly to the peduncle with maturation. There are one to three seeds on the mature ovulate organ, which are roughly circular in outline. Associated leaves are small, with flabellate and dichotomously divided lamina. The new Ginkgo is morphologically intermediate between the Jurassic Ginkgo yimaensis and the extant Ginkgo biloba, but much closer to the latter and essentially of the modern type in ovulate organs. It fills up the wide gap between the Middle Jurassic and Palaeocene in the fossil record of Ginkgo ovulate organs. The finding provides new evidence supporting the reduction hypothesis for Ginkgo evolution. It is likely that the drastic climatic changes during the Late Jurassic and Early Cretaceous were responsible for the transformation of the ovulate organs of the Jurassic G. yimaensis type into the modern G. biloba type.

First Report of Phytophthora ramorum on Camellia japonica in Spain.

Phytophthora ramorum causes shoot and foliar blight on Rhododendron spp., Viburnum spp. (4), Pieris spp. (2), Kalmia latifolia, and Camellia spp. in several European countries (1-4). In December 2002, we received diseased C. japonica growing in containers from several nurseries in Galicia (northwestern Spain). These young camellia plants had leaves with brown-to-black, water-soaked lesions with diffuse borders that expanded into larger blotches resulting in dead leaves and necrotic lesions on the petioles. Eventually the entire plant wilted and died. Tissue from the leading edge of the lesions was transferred to a selective medium (V8 agar supplemented with pimaricin (10 μg/ml), rifampicin (25 μg/ml), hymexazol (5 μg/ml), and benomyl (5 μg/ml)) and incubated for 3 to 4 days at 20°C in the dark. A Phytophthora sp. was isolated, transferred to carrot piece agar (CPA) (4), and incubated in alternating light. Isolates exhibited coralloid mycelium with concentric rings and a radial growth of 2.5 to 3 mm per day at 20°C. The hyaline-to-yellowish chlamydospores were terminal and intercalary, occasionally lateral, and 24 to 74 μm in diameter. The caducous, sympodial, semipapillate sporangia had a length/breadth ratio of 1.8 to 2.1 and a short pedicel (<5 μm) or no pedicel. Oogonia, antheridia, and oospores were produced by pairing the isolates with P. cryptogea A2 tester BBA 63651 (3,4) provided by S. Werres. Oogonia were subspherical and smooth-walled, antheridia were amphyginous, and oospores were plerotic. The internal transcribed spacer-rDNA polymerase chain reaction (PCR) product obtained by using DNA extracted from mycelium and nested PCR with P. ramorum-specific primers was the size reported for P. ramorum (1). Pathogenicity of the isolates was confirmed by inoculating detached leaves of C. japonica. Five isolates were tested on leaves from 15 young plants growing in containers. Three leaves of each plant were detached and inoculated with each isolate. Leaves were dipped for 5 min into a suspension of sporangia and mycelial fragments and maintained at 20°C and 95% humidity. After 15 days, lesions that developed from the petiole base exceeded 25 mm, and the pathogen was consistently reisolated from the lesions. Leaves inoculated with water from sterile CPA plates did not develop symptoms. A C. japonica isolate has been deposited in the Spanish Type Culture Collection (CECT 20519). To our knowledge, this is the first report of P. ramorum on C. japonica in Spain, though the pathogen has been isolated from Rhododendron spp. and Viburnum tinus growing in several nurseries in Galicia.

First Report of Phytophthora palmivora on Grevillea spp. in Italy.

The genus Grevillea (family Proteaceae) comprises over 300 species and is a popular and widely cultivated group of Australian plants. In the last 3 years, numerous potted grevilleas with symptoms of decline associated with a rot of feeder roots were found in ornamental nurseries in Sicily. Aboveground symptoms were reduced growth, yellowing of foliage, wilt, dieback, and death of the entire plant. The disease was observed on many commercial cultivars and was especially severe on G. alpina (mountain grevillea), G. juniperina (juniper-leaf grevillea), G. lavandulacea (lavender grevillea), and G. rosmarinifolia (rosemary grevillea) as well as the hybrid cultivars Clearview David (G. lavandulacea × rosmarinifolia) and Poorinda Rondeau (G. baueri × lavandulacea), while G. lanigera (woolly grevillea) cv. Mount Tamboritha and G. thelemanniana subsp. obtusifolia appeared resistant. A species of Phytophthora was consistently isolated from rotted roots of symptomatic plants using a selective medium (4), and pure cultures were obtained by single-hypha transfers. The species was identified as P. palmivora (E.I. Butler) E.I. Butler on the basis of morphological and cultural characters. On solid media, all isolates produced elliptical to ovoid, papillate sporangia with a mean length/width ratio of 1.8. Sporangia were caducous with a short pedicel (5 μm) and a conspicuous basal plug. All isolates were heterothallic (mating type A1) and produced oogonia and oospores only when paired with A2 mating type reference isolates of P. nicotianae and P. palmivora. Antheridia were amphyginous. Identification was confirmed by electrophoresis of mycelial proteins in polyacrylamide slab gels (1). The electrophoretic patterns of total soluble proteins and six isozymes (alkaline phosphatase, esterase, fumarase, NAD-glucose dehydrogenase, malate dehydrogenase, and superoxide dismutase) of isolates from grevillea were identical to those of a reference isolate of P. palmivora from Coronilla valentina subsp. glauca (2) but distinct from those of reference strains of eight other papillate species of Phytophthora included in Waterhouse's taxonomic group VI. Koch's postulates were fulfilled using 6-month-old rosemary grevillea plants that were transplanted into pots filled with soil that was artificially infested with chlamydospores (50 per gram of soil) produced in submerged cultures (3) by grevillea isolate IMI 390579. Plants were maintained in a glasshouse at 20 to 28°C and watered to field capacity once a week. One month after transplanting, infected plants showed decline symptoms similar to those of naturally infected plants. Control plants grown in pots containing noninfested soil remained healthy. P. palmivora was reisolated from roots of symptomatic plants. It appears that P. palmivora has become a widespread root pathogen in commercial ornamental nurseries in Italy (2).

A reconsideration of Dimeripteris cornuta SCHWEITZER and CAI, a diminutive fossil plant from the Middle Devonian of Yunnan, China

Small plant fragments previously attributed to Dimeripteris cornuta SCHWEITZER and CAI and new specimens are described from the Middle Devonian (Givetian) Xichong Formation of Wuding, Yunnan Province, southwest China. A predominantly trifurcate branching pattern is recognized in lower orders of branching. Erect fusiform sporangia are borne in pairs terminally on a short pedicel on up to three times dichotomously-branching fertile unit. The beaked tips of the paired sporangia point outwards. This plant is distinguished from known plants by the trifurcate branching pattern and sporangia morphology, but is of problematic affinity. The plant is named Tauritheca cornuta (SCHWEITZER and CAI) WANG and BERRY nov. gen. and nov. comb.

First Report of Phytophthora nicotianae and P. citricola Associated with English Walnut Decline in Europe.

English (Persian) walnut (Juglans regia), among the most widely cultivated species of Juglans worldwide, is cultivated primarily for fruit production but also for timber. In the last 10 years, walnut decline causing leaf yellowing, sparse foliage, overall decline, and plant death has increased in Italian commercial orchards. In Italy, Phytophthora cactorum, P. cambivora, P. cinnamomi, and P. cryptogea are associated with this disease (1,4). Over the last 5 years, P. cinnamomi was the most widely isolated and destructive species (1). Recently, a different species of Phytophthora was isolated from diseased roots and soil from around lateral roots of 10 declining trees in two orchards in the Veneto Region of northern Italy. Another species of Phytophthora was isolated consistently from rotted roots of declining walnut trees in two orchards in the Campania Region of southern Italy. Phytophthora spp. were isolated directly from plant material or Rhododendron spp. leaf baiting on soil samples with PARBhy selective medium (10 mg of pimaricin, 250 mg of ampicillin [sodium salt], 10 mg of rifampicin, 50 mg of hymexazol, 15 mg of benomyl, 15 g of malt extract, 20 g of agar in 1,000 ml of H2O). Two species of Phytophthora were identified based on morphological and cultural characteristics (2). The species from trees in the Veneto Region was identified as P. nicotianae. All isolates produced papillate, spherical to obturbinate, occasionally caducous sporangia with short pedicels, terminal and intercalary chlamydospores, and were mating type A2. The species isolated from trees in the Campania Region was identified as P.citricola. Isolates were homothallic, produced semipapillate, persistent, obclavate to obpyriform sporangia, occasionally with two apices, and antheridia paragynous. Identifications were confirmed by comparing restriction fragment length polymorphism patterns of the internal transcribed spacer region of rDNA with those obtained from previously identified species of Phytophthora. Pathogenicity of two isolates each of P. citricola and P. nicotianae was tested on 2-year-old potted walnut seedlings. Inocula were prepared by inoculating sterilized millet seeds moistened with V8 broth with plugs of mycelium and incubated for 4 weeks at 20°C in the dark. Infested seeds were added to potting soil at a rate of 3% (wt/vol). One day later, pots were flooded for 48 h to promote sporulation. Ten noninoculated seedlings were used as the control. Symptoms were assessed 2 months after inoculation. Seedlings inoculated with P. nicotianae developed necrosis of feeder and lateral roots, but only limited infection of taproots. Seedlings inoculated with P. citricola developed necroses at the insertion points of lateral roots. All four isolates produced visible damage to lateral roots on inoculated plants. P. nicotianae and P. citricola were reisolated from respectively infected roots. Results from these inoculations confirmed P. nicotianae and P. citricola as root pathogens of English walnut. Both species were associated with walnut decline as reported in the United States (3). To our knowledge, this is the first report of P. nicotianae and P. citricola on J. regia in Europe.

Studies of Eurya (Ternstroemiaceae) in Taiwan (1), a new endemic species, Eurya septata

Eurya septata (Ternstroemiaceae) is described as a new species endemic to Taiwan. It is most similar to E.chinensis, a species common in Taiwan and southeast China. The new species can be separated from E.chinensis in having septate anthers, shorter pedicels, and more flowers per fascicle.

First Record of Leaf Spots on Prunus laurocerasus in Belgium Caused by Phytophthora cactorum and Peronospora sparsa.

In fall 2000 and 2001, large leaf spots were observed on Prunus laurocerasus. Two different plant pathogens proved to be the cause. Based on morphological characteristics they were identified as Peronospora sparsa (downy mildew) and Phytophthora cactorum. The P. cactorum isolate (CBS 110121) was identified at the Centraalbureau voor Schimmelcultures (Utrecht, the Netherlands). Sporangia were papillate, ovoid, and deciduous, with a short pedicel. The isolate was homothallic. Chlamydospores were present and approximately 40 μm in diameter. Oogonia were 25 to 31 μm in diameter, and the antheridia were paragynous. Peronospora sparsa had been reported to infect Prunus laurocerasus in the United Kingdom (1). In Belgium, cv. Etna was very susceptible, but cvs. Rotundifolia and Marbled White were also infected. Rotundifolia was susceptible to P. cactorum. At first inspection, the two pathogens caused similar leaf symptoms: large, irregular, brown, necrotic spots on the tips, margins, and center of leaves. However, the undersides of leaves infected with Peronospora sparsa were covered with typical gray mycelium, which was absent on leaves infected with P. cactorum. P. cactorum caused concentric circles in the brown spots. Leaf spots caused by P. cactorum developed quickly in a moist chamber. Spots caused by Peronospora sparsa did not enlarge significantly on detached leaves, but in the field it caused serious losses within a few days. To prove the pathogenicity of P. cactorum, Koch's postulates were satisified on five Prunus laurocerasus Etna plants. The fungus was grown on corn meal agar for 1 week until sporangia formed. An agar plug was placed on five wounded leaves per plant and sealed with Parafilm. Inoculated plants were kept under a plastic cover for 1 day at 22°C, then the cover was removed, and the plants were kept at 20°C. Symptom development was visible after 3 days, and P. cactorum was successfully reisolated. This is the first record of P. cactorum and Peronospora sparsa leaf infection on Prunus laurocerasus in Belgium. Reference: (1) G. Hall et al. Plant Pathol. 41:224, 1992.