abstract：:The temperature dependence of freezing-induced xylem cavitation was studied in a Chihuahuan desert population of Larrea tridentata (Zygophyllaceae). Field measurements of wood temperature and xylem embolism were combined with anatomical studies and laboratory measurements of embolism in stem and root samples frozen un...

journal_title：American journal of botany

authors： Martínez-Vilalta J,Pockman WT

更新日期：2002-12-01 00:00:00

abstract：:The amplified fragment length polymorphism (AFLP) method was used to evaluate genetic diversity and to assess genetic relationships within the section Mentha in order to clarify the taxonomy of several interspecific mint hybrids with molecular markers. To this end, genetic diversity of 62 Mentha accessions from differ...

journal_title：American journal of botany

authors： Gobert V,Moja S,Colson M,Taberlet P

更新日期：2002-12-01 00:00:00

abstract：:The vegetative cycle of the foliicolous lichen Phyllophiale, from propagule germination to propagule production, was studied by light microscope observation of thalli colonizing plastic cover slips placed within a lowland tropical forest. Discoid propagules germinated by growth of radially arranged fungal cells and de...

journal_title：American journal of botany

authors： Sanders WB

更新日期：2002-11-01 00:00:00

abstract：:The taxonomic richness of seed plants at different taxonomic levels was compared between temperate East Asia and North America at both continental and semi-continental scales. In each comparison, land area and latitude range were adjusted to a comparable level between the two continental regions. East Asia is signific...

journal_title：American journal of botany

authors： Qian H

更新日期：2002-11-01 00:00:00

abstract：:Temporal and demographic aspects of the growth of Botrychium gallicomontanum and B. mormo were studied for 2 yr. A total of 219 B. gallicomontanum and 412 B. mormo plants were monitored in a prairie and maple-basswood forest, respectively. Growth events were divided into four stages: leaf emergence, leaf separation, s...

journal_title：American journal of botany

authors： Johnson-Groh CL,Lee JM

更新日期：2002-10-01 00:00:00

abstract：:It is often suggested that traits will be integrated, either because of pleiotropy or because natural selection may favor suites of integrated traits. Plant responses to different environments can provide evidence of such integration. We grew Mercurialis annua plants in high-density stands in high irradiance, in neutr...

journal_title：American journal of botany

authors： Sleeman JD,Dudley SA,Pannell JR,Barrett SC

更新日期：2002-09-01 00:00:00

abstract：:Pedilanthus coalcomanensis was described from specimens collected by George B. Hinton in 1941 but was not collected again until 1999, when we found it in a tropical deciduous forest near Tehuantepec, in Chinicuila, Michoacán, Mexico. After analyzing Hinton's original collection notes, we concluded that this is the typ...

journal_title：American journal of botany

authors： Lomelí-Sención JA,Sahagún-Godínez E

更新日期：2002-09-01 00:00:00

abstract：:This paper reports the frequency of spontaneous amphiploids or neopolyploids in experimental interspecific hybrids in two annual sections of Gilia (Polemoniaceae, sects. Arachnion and Gilia, x = 9). In each section the species were intercrossed in numerous hybrid combinations to obtain an array of F1 hybrid types; sev...

journal_title：American journal of botany

authors： Grant V

更新日期：2002-08-01 00:00:00

abstract：:After 120 yr of burial in moist, well-aerated sand, 23 seeds of Verbascum blattaria and two seeds of a Verbascum sp. germinated and produced normal plants (50% germination for Verbascum). After a 6-wk cold treatment, a single seed of Malva rotundifolia germinated also, producing a normal plant (2% germination). Plants...

journal_title：American journal of botany

authors： Telewski FW,Zeevaart JA

更新日期：2002-08-01 00:00:00

abstract：:Maximum parsimony analysis of DNA sequence data from the internal and external transcribed spacer (ITS and ETS) regions of 18S-26S nuclear ribosomal DNA and the 3' trnK intron of chloroplast DNA from over 60 populations of Lasthenia sect. Amphiachaenia yielded a well-supported tree showing that the most common species...

journal_title：American journal of botany

authors： Chan R,Baldwin BG,Ornduff R

更新日期：2002-07-01 00:00:00

abstract：:Developmental and physiological studies of roots are frequently limited to a post-germination stage. In Arabidopsis, a developmental change in the root meristem architecture during plant ontogenesis has not previously been studied and is addressed presently. Arabidopsis thaliana have closed root apical organization, i...

journal_title：American journal of botany

authors： Baum SF,Dubrovsky JG,Rost TL

更新日期：2002-06-01 00:00:00

abstract：:In addition to vegetative remains, fertile remains from ten plants, representing seven distinct taxa whose size and complexity are much greater than most contemporaneous fossils, are reported from late Ludlow (Ludfordian) sediments of Bathurst Island in Nunavut, Canada. Evidence for the age of these beds is gathered f...

journal_title：American journal of botany

authors： Kotyk ME,Basinger JF,Gensel PG,de Freitas TA

更新日期：2002-06-01 00:00:00

abstract：:We examined the effects of size and spatial isolation of fens on the isozyme variability of 17 populations of Swertia perennis. This long-lived perennial is a locally abundant fen specialist in Switzerland, where wetlands have been strongly fragmented. Isozyme variability was comparable to other outcrossing plants (A ...

journal_title：American journal of botany

authors： Lienert J,Fischer M,Schneller J,Diemer M

更新日期：2002-05-01 00:00:00

abstract：:Marchantia inflexa, a dioecious thallose liverwort, is sexually dimorphic in clonal expansion traits. We used selection analyses to measure the magnitude and direction of selection on clonal fitness to uncover possible mechanisms for the maintenance of preadult sexually dimorphic characters. We planted replicates of g...

journal_title：American journal of botany

authors： Fuselier L,McLetchie N

更新日期：2002-04-01 00:00:00

abstract：:Madagasikaria andersonii is described here as a new genus and species of Malpighiaceae from Madagascar. The phylogenetic placement of Madagasikaria was estimated by using combined data from ndhF and trnL-F chloroplast sequences and phytochrome (PHYC) and ITS nuclear sequences. It forms a strongly supported clade with ...

journal_title：American journal of botany

authors： Davis CC

更新日期：2002-04-01 00:00:00

abstract：:We analyzed the effects of temporal variation in floral display size (number of flowers open at one time on a plant) on the rate of pollen removed and receipt of individual flowers for the sequential blooming plant Narthecium asiaticum (Liliaceae). Because of the acropetal blooming of this species, the display sizes w...

journal_title：American journal of botany

authors： Ishii HS,Sakai S

更新日期：2002-03-01 00:00:00

abstract：:Morphology and development of the female flowers in Geonoma interrupta are described and compared with other taxa within Arecaceae. Inflorescences are pleiothyrses. Cincinni are immersed in pits and arranged according to the Fibonacci pattern along the rachillae. The gynoecium is composed of three free carpels in earl...

journal_title：American journal of botany

authors： Stauffer FW,Rutishauser R,Endress PK

更新日期：2002-02-01 00:00:00

abstract：:Cacti are a large and diverse group of stem succulents predominantly occurring in warm and arid North and South America. Chloroplast DNA sequences of the trnK intron, including the matK gene, were sequenced for 70 ingroup taxa and two outgroups from the Portulacaceae. In order to improve resolution in three major grou...

journal_title：American journal of botany

authors： Nyffeler R

更新日期：2002-02-01 00:00:00

abstract：:Species of Collinsia and Tonella, the two sister genera of self-compatible annuals that constitute tribe Collinsieae, show extensive variation in floral size and morphology and in patterns of stamen and style elongation during the life of the flower (anthesis). We used a nuclear ribosomal ITS phylogeny, independent co...

journal_title：American journal of botany

authors： Armbruster WS,Mulder CP,Baldwin BG,Kalisz S,Wessa B,Nute H

更新日期：2002-01-01 00:00:00

abstract：:This study examined variation in two components of acorn production. Percentage of bearing ramets (stems) and number of acorns per bearing ramet were examined in five clonal oaks in three xeric habitats of south-central peninsular Florida in relation to ramet size within and between species and vegetative associations...

journal_title：American journal of botany

authors： Abrahamson WG,Layne JN

更新日期：2002-01-01 00:00:00

abstract：:Zeuxine gracilis, Zeuxine strateumatica, and Eulophia sinensis are wild orchids with different breeding systems and colonizing abilities. Zeuxine gracilis is an outcrosser with restricted distribution, whereas S. strateumatica is an apomictic colonizer found only in newly available open habitats. Eulophia sinensis is ...

journal_title：American journal of botany

authors： Sun M,Wong KC

更新日期：2001-12-01 00:00:00

abstract：:The boreotropical flora concept suggests that relictual tropical disjunctions between Asia and the Americas are a result of the expansion of the circumboreal tropical flora from the middle to the close of the Eocene. Subsequently, temperate species diverged at high latitudes and migrated to other continents. To test t...

journal_title：American journal of botany

authors： Azuma H,García-Franco JG,Rico-Gray V,Thien LB

更新日期：2001-12-01 00:00:00

abstract：:The pathways of micro- and megagametophyte development in Agave fourcroydes (henequén) and A. angustifolia were studied. We used histology and light microscopy to observe anther ontogeny and ovary differentiation in relation to flower bud size. Both species have the same sexual reproductive strategies and gametophyte ...

journal_title：American journal of botany

authors： Piven NM,Barredo-Pool FA,Borges-Argáez IC,Herrera-Alamillo MA,Mayo-Mosqueda A,Herrera-Herrera JL,Robert ML

更新日期：2001-11-01 00:00:00

abstract：:Sequence data from the intron and spacer of the trnL-F chloroplast region elucidate the phylogenetic relationships of the tribe Diseae (Orchidoideae: Orchidaceae). Within Diseae, 41 species of Disa, two of Brownleea, three of Satyrium, and two of Corycium were included, with five species of Habenaria sensu lato (Orchi...

journal_title：American journal of botany

authors： Bellstedt DU,Linder HP,Harley EH

更新日期：2001-11-01 00:00:00

abstract：:Sex allocation models predict that cosexuality is stabilized by high allocation to attractive structures in pollen-limited species or by high allocation to shared structures that contribute to both genders. High investment in unilateral fixed costs favor the evolution of dioecy or gender change. With these predictions...

journal_title：American journal of botany

authors： Méndez M

更新日期：2001-10-01 00:00:00

abstract：:The utility of the PCR-based AFLP technique (polymerase chain reaction; amplified fragment length polymorphisms) was explored in elucidating details of polyploid evolution in the Eurasian orchid genus Dactylorhiza. We emphasized Swedish taxa but also included some material from the British Isles and elsewhere in Europ...

journal_title：American journal of botany

authors： Hedrén M,Fay MF,Chase MW

更新日期：2001-10-01 00:00:00

abstract：:Pollinator-mediated natural selection has been shown to act on phenotypic variation in floral morphology, and this variation has often been demonstrated to be heritable, but few details are available concerning the sources of floral variation. We examined phenotypic variation in seven floral traits in wild radish (Rap...

journal_title：American journal of botany

authors： Williams JL,Conner JK

更新日期：2001-09-01 00:00:00

abstract：:The circumscription and relationships of genera within the tribe Melanthieae (29 representative taxa) were evaluated using parsimony analyses of ITS (nuclear ribosomal) and trnL-F (plastid) DNA sequence data, alone and in combination. Proposed new generic circumscriptions, strongly supported by the tree statistics and...

journal_title：American journal of botany

authors： Zomlefer WB,Williams NH,Whitten WM,Judd WS

更新日期：2001-09-01 00:00:00

abstract：:We sequenced the nuclear small subunit ribosomal DNA coding region from 20 members of the Bangiophycidae and from two members of the Florideophycidae to gain insights into red algal evolution. A combined alignment of nuclear and plastid small subunit rDNA and a data set of Rubisco protein sequences were also studied t...

journal_title：American journal of botany

authors： Müller KM,Oliveira MC,Sheath RG,Bhattacharya D

更新日期：2001-08-01 00:00:00

abstract：:We transplanted Nuphar variegata with submersed leaves only into natural lake sediments in pH-, [CO(2)]-, depth-, and temperature-controlled greenhouse tanks to test the hypotheses that more fertile sediment, lower free [CO(2)], and shallower depth would all stimulate the development of floating leaves. Sediment highe...

journal_title：American journal of botany

authors： Titus JE,Gary Sullivan P

更新日期：2001-08-01 00:00:00

abstract：:Restriction fragment length polymorphism (RFLP) analysis of chloroplast (cp) DNA is a powerful tool for the study of microevolutionary processes in land plants, yet has not previously been applied to seaweed populations. We used cpDNA-RFLP, detected on Southern blots using labeled total plastid DNA, to search for intr...

journal_title：American journal of botany

authors： Wattier RA,Davidson AL,Ward BA,Maggs CA

更新日期：2001-07-01 00:00:00

abstract：:Recent surveys of seed coat morphology in Lobelioideae (Campanulaceae) have demonstrated the systematic utility of such data in the subfamily and led to a revision of the supraspecific classification of Lobelia. Expanding upon these studies, we examined via scanning electron microscopy 41 seed accessions, emphasizing ...

journal_title：American journal of botany

authors： Buss CC,Lammers TG,Wise RR

更新日期：2001-07-01 00:00:00

abstract：:Paddy fields are one of the dominant anthropogenic sources of methane emission to the atmosphere, and the main passageway of methane from paddy soil is through the rice plant. However, the effect of aquatic weeds on methane emission from rice paddies has not been properly evaluated yet. Methane emission from weeded po...

journal_title：American journal of botany

authors： Inubushi K,Sugii H,Nishino S,Nishino E

更新日期：2001-06-01 00:00:00

abstract：:Correlations were examined between habitat characters and clonal structures determined by the RAPD (random amplified polymorphic DNA) assay in five populations of Oryza rufipogon in China. Nine of 175 decameric primers were used in the study because they reproducibly amplified polymorphisms. The extent of clonality to...

journal_title：American journal of botany

authors： Xie ZW,Lu YQ,Ge S,Hong DY,Li FZ

更新日期：2001-06-01 00:00:00

abstract：:Gregor Mendel was a 19(th) century priest and botanist who developed the fundamental laws of inheritance. The year 2000 marked a century since the rediscovery of those laws and the beginning of genetics. Although Mendel is now recognized as the founder of genetics, significant controversy ensued about his work through...

journal_title：American journal of botany

authors： Fairbanks DJ,Rytting B

更新日期：2001-05-01 00:00:00

abstract：:The relationship between pollen and progeny performance has been a subject of many studies but the evidence for pollen-tube growth rate as an indicator of progeny fitness is equivocal. We used an anemophilous tree, Betula pendula, to examine the relationship between pollen-tube growth rate and seed and seedling perfor...

journal_title：American journal of botany

authors： Pasonen HL,Pulkkinen P,Käpylä M

更新日期：2001-05-01 00:00:00

abstract：:In Nicotiana attenuata, systemic induction of heat-shock proteins (Hsps) was detected in response to the treatment of single leaves by either heat shock, mechanical damage, or exogenous application of methyl jasmonate (MJ). All treatments increased the abundance of members of the 70-kD Hsp (Hsp70) family and induced s...

journal_title：American journal of botany

authors： Hamilton Iii EW,Coleman JS

更新日期：2001-05-01 00:00:00

abstract：:Ontogenetic trends in the wood structure of Nepalese Rhododendron were studied in 15 specimens of two tree and four subtree species. Average growth ring width was constant from pith to bark in spite of occurrences of extremely narrow, false, or discontinuous rings. Vessel density, vessel area, vessel element length, a...

journal_title：American journal of botany

authors： Noshiro S,Suzuki M

更新日期：2001-04-01 00:00:00

abstract：:Partial cambial mortality is a growth form that is characteristic of Pinus aristata trees. To better elucidate their cambial death pattern, tree size and aspect of cambial death data were gathered from three Pinus aristata forests in central Colorado, USA. Stripping frequency tended to be higher for larger diameter cl...

journal_title：American journal of botany

authors： Schauer AJ,Schoettle AW,Boyce RL

更新日期：2001-04-01 00:00:00

abstract：:Additional information on the morphology of the vegetative ultimate branches of Archaeopteris roemeriana was obtained by uncovering compression specimens collected in Upper Devonian deposits in Belgium. For the first time, anisophylly, previously inferred from anatomical studies, is demonstrated on one species of the ...

journal_title：American journal of botany

authors： Fairon-Demaret M,Leponce I

更新日期：2001-04-01 00:00:00