Pumila Var Research Articles

Molecular Evidence for an Asian Origin and a Unique Westward Migration of Species in the Genus Castanea via Europe to North America

The genus Castanea (Fagaceae), which contains three sections and seven species, is widely distributed in the deciduous forests of the Northern Hemisphere. The phylogeny of Castanea was estimated using DNA sequence data from five different regions of the chloroplast genome. Sequencing results support the genus Castanea as a paraphyletic group with C. crenata, the Japanese chestnut, representing an early divergence in the genus. The three Chinese species form a strongly supported sister clade to the North American and European clade. A unique westward expansion of extant Castanea species is hypothesized with Castanea originating in eastern Asia, an initial diversification within Asia during the Eocene, followed by intercontinental dispersion and divergence between the Chinese and European/North American species during the Oligocene and a split between the European and North American species in the early Miocene. The differentiation within North America and China might have occurred in late Miocene or early Pliocence. The North America species are supported as a clade with C. pumila var. ozarkensis, the Ozark chinkapin, as the basal lineage, sister to the group comprising C. pumila var. pumila, the Allegheny chinkapin, and C. dentata, the American chestnut. Morphological evolution of one nut per bur in the genus may have occurred independently on two continents.

Vegetative Compatibility Grouping and Pathogenicity of Colletotrichum gloeosporioides Isolates from Different Host Plants

A total of 57 isolates of Colletotrichum gloeosporioides were recovered from diseased tissues of Hall's crab apple (Malus haliana), 3 cultivars of edible apple (M. pumila var. dulcissima), red pepper (Capsicum annum), and grapevine (Vitis vinifera) fruits. All isolates showed strong virulence on their own host plants. Isolates from edible apple exhibited high level of cultivar specificity in pathogenicity tests. Ten isolates from apple cultivar 'Fuji' were virulent on 'Jonathan' and 'Rall's Genet'. However, 12 isolates from 'Jonathan' and 'Rall's Genet' were not virulent on 'Fuji'. Among the 24 isolates from red pepper, only seven and two isolates were infective on edible apple and grapevine fruits, respectively. All six isolates from grapevine were only virulent on their own host. These isolates were grouped into five vegetative compatibility groups (VCGs), A, B, C, D, and E, by demonstrating heterokaryosis through complementation using nitrate-nonutilizing (nit) mutants. Among them, isolates belong to VCG-A and VCG-D accounted for 24 and 17 isolates； those in VCG-A exhibited wide host range involving Hall's crab apple, all three edible apple cultivars, and red pepper. On the other hand, isolates of VCG-D and VCG-E showed limited host range specific to red pepper and grapevine, respectively. Taken together, the data suggest that among C. gloeosporioides isolates, the concepts of pathotype and/or forma specialis may exist, and that three is a relationship between host specificity and VCG grouping among C. gloeosporioides isolates.

Allozyme variation in endangered Castanea pumila var. pumila.

Allozyme genetic variation in 12 populations of the endangered Castanea pumila var. pumila (Allegheny chinkapin), sampled across the natural range of the species in the United States, was evaluated using 11 loci from seven enzyme systems. At the species level, the percentage of polymorphic loci (Ps) was 72.7 %, the mean number of alleles per locus (As) was 1.9, the mean number of alleles per polymorphic locus (APs) was 2.3, the effective number of alleles per locus (Aes) was 1.5 and the genetic diversity (Hes) was 0.296. At the population level, Pp = 49.2 %, Ap = 1.5, Aep = 1.4, APp = 2.1 and Hep = 0.21. Most of the allozyme variation (70 %) in C. pumila var. pumila occurred within populations. Wright's gene flow rate [Nm(W)] was as low as 0.57. Population differentiation along the species range was not detected. Populations of C. pumila var. pumila in Florida had the most variable levels of genetic diversity, but populations in Virginia and Mississippi also showed high levels. Based on the results of this study, conservation management strategies are discussed.

Larvicidal Activity of the Essential Oils and Methanol Extracts of Malaysian Plants on Aedes aegypti

A total of 17 methanol extracts and nine essential oils of Malaysian plants were investigated for their larvicidal activity against Aedes aegypti. Acute mortality of the fourth instar larvae was determined according to the standard WHO method. Among the samples studied, the essential oils of Cinnamomum impressicostatum Kosterm., C. microphyllum Ridl. and Curcuma domestica Valeton showed significant effects with LC 50 values of 13.7, 20.6 and 20.9µg/ml, respectively. Except for Zingiber cassumunar Roxb., the essential oils of the other species were also effective against the larvae with LC 50 values less than 200µg/ml. Of the methanol extracts, Garcinia praniana King, G. griffithii T. Anders, Labisia pumila var. alata Lindl., L. pumila var. pumila and Mitragyna speciosa Korth. showed relatively high activity with LC 50 values ranging from 103-271µg/ml. The methanol extracts were generally less effective than the essential oils with most extracts exhibiting LC 50 values greater than 500µg/ml.

Rank and typification in North American dwarf cherries, and a key to the taxa

SummaryCatling, P. M., McKay‐Kuja, S. M. & Mitrow, G.: Rank and typification in North American dwarf cherries, and a key to the taxa. – Taxon 48: 483‐488. 1999. – ISSN 0040‐0262.Pubescent twigs are characteristic of Prunus susquehanae, a plant of acid, sandy or rocky barrens, whereas other members of the dwarf cherry complex, mostly of alkaline or neutral substrates of prairies, lakeshores, and scree slopes, have glabrous twigs. The correlation of this character with habit, ecology, and other morphological characters provides a basis for treating P. susquehanae (= P. pumila var. cuneata) as a distinct species. Related taxa are best treated as varieties of P. pumila. Current application of the scientific names is confirmed. P. pumila is lectotypified by a Miller figure, but in view of its ambiguity, a supporting epitype is also selected. Lectotypes are also designated for P. besseyi and P. susquehanae. A key and conspectus are included.

Evaluation of the Genetic Diversity Castanea pumila var. ozarkensis through Isozyme Analysis and DNA Amplification Fingerprinting

The genetic diversity within and between four geographic populations of the Ozark chinkapin was evaluated and partitioned in order to gain an understanding of the overall genetic diversity and structure of this species, which will be instrumental for its preservation and germplasm enhancement. Nuts of chinkapin trees along the natural range of the species in the Sylamore Ranger District of the Ozark National Forest in Arkansas were collected and evaluated with isozyme and RAPD markers scattered across the genome. Allozyme differences were detected among the geographic populations. Allele frequencies will be determined and subjected to genetic diversity statistics. A conservation plan will be recommended.

The decline and current status of the dune race of the Dwarf Cherry, Prunus pumila var. pumila, on the Canadian shores of the lower Great Lakes

The decline and current status of the dune race of the Dwarf Cherry, Prunus pumila var. pumila, on the Canadian shores of the lower Great Lakes

厳寒期におけるリンゴ属植物の耐凍性と過酸化物代謝

木本類植物の耐凍性差の生化学的機構を明らかにするために, 厳寒期におけるリンゴ属植物 (Malus) 9種 (3品種を含む) を用いて, 耐凍性と過酸化物代謝の関連について検討した.1. リンゴ属植物の枝の耐凍性は次のように高低4階級に分けられた.低いもの: M. pumila var. domestica ('紅玉')M. hallianaやや低いもの: M. pumila var. domestica ('デリシャス'), M. asiaticaやや高いもの: M. pumila var. domestica ('旭'),M. prunifolia var. ringo, M. sieboldii,M. sieboldii var. arborescens,M. platycarpa高いもの: M. baccata, M. astracanica2. 過酸化物分解系の酵素活性は皮層部と木部のいずれにおいてもM. pumila var. domesticaの3品種とM.astracanica, M. asiatica, M. baccataで高く, M. prunifolia var. ringo, M. halliana, M. sieboldii, M. sieboldii var. arborescens, M. platycarpaで低かった.主要な過酸化物生成系である電子伝達系のNADH-CcRとCcO活性も同様の結果を得た. 皮層部と木部のいずれにおいても, 一部の例外を除いて過酸化物分解系の酵素活性と過酸化物生成系の酵素活性との間には有意の相関関係がみられ, 特にG6PDH活性とNADH-CcR (皮層部, r=+0.944**;木部, r=+0.877**) あるいはCcO活性 (皮層部, r=+0.973**;木部, r=+0.937**) との間に高い相関係数が得られた.3. NADH-CcR活性/G6PDH活性比あるいはCcO活性/G6PDH活性比を酸化ストレスに対する感受性を表す細胞内状態の指標 (oxidizability index, OI) と定義し, OI値と枝の耐凍性の関係を検討した. 枝の耐凍性と皮層部のOI値の間には一定の関係がみられなかった. しかし, 枝の耐凍性と木部のNADH-CcR活性/G6PDH活性比 (r=-0.793**) あるいはCcO活性/G6PDH活性比 (r=-0.662*) の間には負の高い相関係数が得られ, 枝の耐凍性は木部組織のOI値が高い種あるいは品種ほど低いことが示された.以上の結果から, 厳寒期におけるリンゴ属植物の枝の耐凍性は木部の過酸化物代謝と密接に関係しているものと考えられる.

Vitrification of Crabapple, Pear, and Geum on Gellan Gum-solidified Culture Medium

Shoots of `Almey' crabapple [Malus baccata (L.) Borkh. × M. pumila var. niedzwetzkyana (Dieck) Schneid.], `Seckel' pear (Pyrus communis L.), and `Mrs. Bradshaw' geum (Geum quellyon Sweet.) were cultured on Murashige and Skoog (MS) medium supplemented with 8.8 μm BA and containing 0.1% to 0.4% Gelrite. Comparative shoot proliferation and vitrification were determined on Phytagar-solidified medium. Shoot proliferation, culture fresh weight, and vitrification declined in crabapple and geum with increasing Gelrite concentration. Pear proliferation and fresh weight increased with increasing Gelrite levels, but all shoots were vitrified. There were differences in the vitrification response between pear and the other two genera. The percent dry weight of vitrified cultures on Gelrite-containing media was generally higher than that of nonvitrified cultures on medium containing Phytagar. Vitrification precludes using low Gelrite concentrations for propagating these plants. Chemical name used: N-(phenylmethyl) -1H-purin-6-amine (BA).

Mineral Nutrient Status of Crabapple and Pear Shoots Cultured in Vitro on Varying Concentrations of Three Commercial Agars

Abstract Shoot tips of ‘Almey’ crabapple [Malus baccata (L.) Borkh. × M. pumila var. Niedzwetzkyana (Dieck) Schneid.] and ‘Seckel’ pear (Pyrus communis L.) were cultured on Murashige and Skoog (MS) medium containing 8.8 µm BA. Media were solidified with either Bacto-agar, Phytagar, or TC agar at concentrations varying from 0.3% to 1.2%. Explant nutrient levels were influenced both by agar brand and concentration. The trends in nutrient composition, although not identical, tended to be similar for both genera. Increasing agar concentrations resulted in increased P, Fe, Zn, and Al in the explant and reduced Ca, Mg, and Mn levels. Although striking variations in many elements occur both in agar brands and in explants cultured on media containing similar concentrations of different agar brands, variations in shoot proliferation and growth of explants cannot be explained on the basis of variations in individual elements. From the nutritional standpoint, the alterations in the elemental composition of the basal medium by the addition of specific agars best explain variations induced by different agar brands. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA).

Influence of Two Commercial Agars on In Vitro Shoot Proliferation of ‘Almey’ Crabapple and ‘Seckel’ Pear

Abstract Shoot tips of ‘Almey’ crabapple [Malus baccata (L.) Borkh. × M. pumila var. niedzwetzkyana (Dieck) Schneid.] and ‘Seckel’ pear (Pyrus communis L.) were cultured on Murashige and Skoog (MS) medium containing 2 mg/liter 6-benzylamino purine (BA). The culture medium contained either TC agar or Bacto-agar at concentrations ranging from 0% to 1.2%. Optimum shoot proliferation in ‘Almey’ was obtained on media containing 0.3% of either agar. Increasing agar levels reduced shoot proliferation and shoot growth, but the reduction was especially severe with Bacto-agar. The differences in shoot proliferation between the 0.3% and 0.6% agar concentrations continued to be exhibited with Bacto-agar but not with TC agar when Mason jars, rather than 25 × 150-mm tubes, were the culture vessels. Shoot proliferation in ‘Seckel’ was best on medium containing 0.6% Bacto-agar; higher concentrations decreased shoot proliferation and shoot growth. TC agar did not influence fresh weight of ‘Seckel’ cultures, but increasing concentrations resulted in increased shoot proliferation.

Influence of Agar Concentration on in Vitro Shoot Proliferation of Malus sp. ‘Almey’ and Pyrus communis ‘Seckel’1

Abstract Shoot tips of ‘Almey’ crabapple [Malus baccata (L.) Borkh. × M. pumila var. niedzwetzkyana (Dieck) Schneid.] and ‘Secke!’ pear (Pyrus communis L.) were cultured on Murashige and Skoog medium supplemented with 2 mg/liter 6-benzylamino purine and agar levels ranging from 0 to 1.2%. The greatest shoot proliferation and shoot growth in ‘Almey’ occurred on medium containing 0.3% agar. Higher agar concentrations decreased both shoot proliferation and shoot growth. Increasing agar concentrations resulted in decreased shoot growth in ‘Seckel’, but shoot proliferation was significantly greater at concentrations of 0.6% and higher as compared to 0.3% or lower. Autoclaving caused an acidification of the medium. The addition of agar reduced media acidification. This pH variation does not explain the effect of agar on shoot proliferation and growth.

Sorbitol and sucrose as carbon source for callus culture of some species of the Rosaceae

Initiation of stem callus cultures on a nutrient medium with either 3% sucrose and (or) 3% sorbitol as carbon source was attempted with 17 species selected from the following genera of the Rosaceae: Amelanchier, two spp.; Crataegus, one sp.; Malus, one sp.; Prunus, nine spp.; Pyrus, one sp.; Sorbus, two spp.; and Spiraea, one sp. In the case of Malus pumila var. niedzwetzkyana (crabapple), sucrose and sorbitol media were equally effective in callus initiation, and equal growth was maintained on these media. Callus of Spiraea vanhouttei was initiated only on sucrose medium and no callus of Prunus tenella formed on either medium. With all other species, callus was initiated and (or) gave better growth on further subculture on sucrose than on sorbitol medium, except for Prunus persica (peach), which grew better on sorbitol.

String Bog in Southern Wisconsin

String bog or "Strangmoor" patterns have been identified in Cedarburg Bog, 25 miles north of Milwaukee, Wisconsin. This is about 200 miles south of the southernmost string bog location previously reported near Seney, Michigan. The string bog consists of slightly elevated ridges and islands with cedar (Thuja occidentalis), tamarack (Larix laricina), bog birch (Betula pumila var. glandulifera), leatherleaf (Chamaedaphne calyculata var. angustifolia), and other woody growth alternating with flat, wet sedge mat areas. This string bog, in common with others in North America and Eurasia, is found on a slightly sloping surface; the alternating ridges and flats are at right angles to the direction of slope or the direction of water flow. Presumably this orientation is indicative of the important role of water movement in pattern formation.

CHARACTERISTICS OF A HYBRID BIRCH AND ITS PARENT SPECIES

The ranges of variation in 24 morphological characteristics, 3 anatomical characteristics, and 1 chemical characteristic were studied in a Minnesota population consisting of 150 bog birches (Betula pumila var. glandulifera), 150 paper birches (B. papyrifera), and 47 individuals of their natural hybrid (B. × sandbergii). The hybrid resembled paper birch in having few stems and a long leaf petiole, but was intermediate between its parents in stem height and diameter, dimensions and positions of male and female catkins, size of fruit wings, and 10 leaf characteristics. Hybrid pollen was as large as that of paper birch. In bark color and exfoliation the hybrid group covered the range of both parents, but most hybrids resembled bog birch in bark characteristics. Shape of fruit bracts was different for each taxon. The hybrid was intermediate in leaf midvein anatomy, but resembled bog birch in number of stomates and paper birch in stomatal size. Paper chromatography revealed the presence of unidentified fluorescent compounds in the inner bark. Chromatographic results permitted identification of the parental species but lacked consistency in the hybrids.

THE BIOLOGICAL STATUS OFBETULA ANDREWSIIA. NELS.

It has been known for many years that interspecific hybridization within the genus occurs more or less freely in nature. Woodworth (1929) states that at least 15 recognized hybrids occur in the genus, including pumila x lenta, populifolia x papyrifera, verrucosa x papyrifera, and others. Rosendahl (1916) also reported and analyzed hybridization within the genus, including a cross involving papyrifera and pumila var. glandulifera. In addition, is known to be a polyploid genus (Woodworth, 1929). This paper' deals with the first instance in which hybridization has been reported involving papyrifera and occidentalis. Wherever two species likely to hybridize grow together, and conditions are more favorable to one than to the other, introgressive hybridization may occur. Anderson (1949) has described this phenomenon as a contamination of the germplasm of one species by the germplasm of the other. The species less favored by present conditions may gradually be absorbed by the other, and the external characteristics of the hybrid derivatives will be more and more those of the best preadapted species. In the fall of 1906, Mr. Darwin M. Andrews, a nurseryman, discovered a small grove of paper-barked birches on the northwest slope of Green Mountain, a high foothill immediately southwest of Boulder, Colorado. Dr. Aven Nelson, to whom Andrews had sent specimens of the birch for identification, published a note (Nelson, 1907) drawing attention to the Andrews collection. The somewhat nvunicrl character' of the nrecimpno, and the geographic isolation of this birch community led Nelson to believe that these plants might constitute a new species, distinct from pap yrifera Marsh, the commori paper-barked tree of northern and eastern North America. However, because of the incompleteness of the specimens before him, and because of his inexperience with 'the population in the field, Nelson only tentatively named this birch Betula andrewsii, which name was, of course, a nomen provisiorum and therefore not valid until its subsequent publication in Coulter and Nelson, New Manual of Botany of the Central Rocky Mountains (1909). Bertram T. Butler (1909), in his taxonomic revision of the paper birches, did not think there were sufficient grounds for separating andrewsii from papyrifera. Dr. Francis Potter Daniels (1911), in his Flora of Boulder, Colorado, and Vicinity, formally reduced andrewsii to a trinomial, papyrifera andrewsii (A. Nels.) Daniels. Daniels' reduction of andrewsii to subspecific rank may have been a factor in a subsequent neglect of the problem. At least, recent authors of tree' manuals have not attempted to determine further the possible relationships of andrewsii. The status of andrewsii has remained unsettled to the present time. The herbarium material of this taxon consisted, until recently, of the type collection (a branch with yellowed leaves and fragmented aments, plus a strip of bark) collected in the fall of 1906, and a branch collected early the following year. This collection is in the Rocky Mountain Herbarium'of the University of Wyoming at Laramie. A photograph of the tree

Cytological Studies on the Betulaceae. IV. Betula, Carpinus, Ostrya, Ostryopsis

1. Betula lutea from Minnesota is hexaploid as is the New England plant. 2. B. papyrifera and its varieties have interesting chromosome numbers. B. papyrifera has the haploid number of thirty-five; B. papyrifera var. cordifolia has twenty-eight; B. papyrifera var. subcordata has twenty-eight; B. papyrifera var. kenaica has thirty-five; B. papyrifera var. occidentalis has forty-two. It is hoped that this will help to explain the polymorphism in the group. 3. B. pumila var. glandulifera has twenty-eight pairs of chromosomes. 4. x B. purpusii (B. lutea x pumila var. glandulifera) presents another complete document, taxonomically and cytologically, of natural hybridization. 5. Carpinus, Ostrya, and Ostryopsis species have eight as the fundamental number of chromosomes. 6. Carpinus betulus var. fastigiata is octoploid with thirty-two chromosomes as the reduced number. 7. Carpinus cordata shows all the cytological characteristics of a hybrid and is accordingly suspected of having a heterozygotic ancestry. It ma...