abstract：:The utility of regression and correspondence models for deducing climate from leaf physiognomy was evaluated by the comparative application of different predictive models to the same three leaf assemblages. Mean annual temperature (MAT), mean annual precipitation (MAP), and growing season precipitation (GSP) were esti...

journal_title：American journal of botany

authors： Wiemann MC,Manchester SR,Dilcher DL,Hinojosa LF,Wheeler EA

更新日期：1998-12-01 00:00:00

abstract：:Phylogenetic relationships were determined in the Araucariaceae, which are now found mainly in the Southern Hemisphere. This conifer family was well diversified and widely distributed in both hemispheres during the Mesozoic era. The sequence of 1322 bases of the rbcL gene of cpDNA was determined from 29 species of Ara...

journal_title：American journal of botany

authors： Setoguchi H,Asakawa Osawa T,Pintaud JC,Jaffré T,Veillon JM

更新日期：1998-11-01 00:00:00

abstract：:Sex ratio and sexual dimorphism in physiology and growth were studied in the dioecious tree Ilex aquifolium at two localities in northern Spain. Genet sex ratio was significantly male biased in one locality but not in the other. However, ramet and flowering ramet sex ratios were male biased at both study sites. Males ...

journal_title：American journal of botany

authors： Obeso JR,Alvarez-Santullano M,Retuerto R

更新日期：1998-11-01 00:00:00

abstract：:Very little is known regarding how repetitive elements evolve inpolyploid organisms. Here we address this subject by fluorescent insitu hybridization (FISH) of 20 interspersed repetitive elements tometaphase chromosomes of the cotton AD-genome tetraploid Gossypiumhirsutum and its putative A- and D-genome diploid ances...

journal_title：American journal of botany

authors： Hanson R,Zhao XP,Islam-Faridi MN,Paterson A,Zwick M,Crane C,McKnight T,Stelly D,Price HJ

更新日期：1998-10-01 00:00:00

abstract：:Bumble bee pollinated Chamaecrista fasciculata provides pollen as the sole reward to its pollinators. Male sterility, expressed as an absence or nearly complete absence of pollen production, occurs in low frequency in populations of C. fasciculata. Here we describe experiments, using C. fasciculata, to examine frequen...

journal_title：American journal of botany

authors： Williams HL,Fenster CB

更新日期：1998-09-01 00:00:00

abstract：:Phylogenetic analysis of DNA sequences of the chloroplast genes rcbL and ndhf revealed a highly supported clade composed of the families Plantaginaceae, Callitrichaceae, and Hippuridaceae in close association with the model organism Antirrhinum majus and other members of family Scrophulariaceae. Plantago has miniature...

journal_title：American journal of botany

authors： Reeves P,Olmstead R

更新日期：1998-08-01 00:00:00

abstract：:Field surveys of cynipid gall-inducer occurrences on Quercus species were conducted in Florida, North Carolina, and Pennsylvania, USA. All cynipids demonstrated strong host species and organ fidelity. One result of this specialization is effective niche partitioning among cynipids. The host-association patterns of the...

journal_title：American journal of botany

authors： Abrahamson W,Melika G,Scrafford R,Csoka G

更新日期：1998-08-01 00:00:00

abstract：:Recent discoveries of fossil reproductive structures from deposits of the Raritan Formation in New Jersey (Turonian, Upper Cretaceous, ~90 million years BP) include a previously undescribed representative of the Order Capparales. The fossils are usually charcoalified with three-dimensional structure and excellent anat...

journal_title：American journal of botany

authors： Gandolfo M,Nixon K,Crepet W

更新日期：1998-07-01 00:00:00

abstract：:Self-incompatibility (SI) is an effective method for limiting self-fertilization in flowering plant species, but there are circumstances in which an otherwise functional SI system may fail. One of the most intriguing of these is the induction of selfing by mixed loads of self and heterospecific pollen (the mentor effe...

journal_title：American journal of botany

authors： Desrochers A,Rieseberg L

更新日期：1998-06-01 00:00:00

abstract：:Aralia sect. Aralia (Araliaceae) consists of approximately eight species disjunctly distributed in Asia and North America. Phylogenetic and biogeographic analyses were conducted using sequences of the internal transcribed spacer regions of the nuclear ribosomal DNA. Aralia racemosa from eastern North America was siste...

journal_title：American journal of botany

authors： Wen J,Shi S,Jansen R,Zimmer E

更新日期：1998-06-01 00:00:00

abstract：:Nuclear DNA contents (4C) were estimated by Feulgen microdensitometry in 27 species of slipper orchids. These data and recent information concerning the molecular systematics of Cypripedioideae allow an interesting re-evaluation of karyotype and genome size variation among slipper orchids in a phylogenetic context. DN...

journal_title：American journal of botany

authors： Cox A,Abdelnour G,Bennett M,Leitch I

更新日期：1998-05-01 00:00:00

abstract：:Lxm1-O, a dominant EMS (ethyl methanesulfonate) induced mutation in maize (Zea mays, Poaceae), was originally reported to affect the blade/sheath boundary over the midrib region of the leaf. Here we present a more extensive analysis of the Lxm phenotype in nine different inbred lines. Lxm leaves are longer and narrowe...

journal_title：American journal of botany

authors： Schichnes D,Freeling M

更新日期：1998-04-01 00:00:00

abstract：:Evolutionary relationships among representatives of Apiaceae (Umbelliferae) subfamily Apioideae have been inferred from phylogenetic analyses of nuclear ribosomal DNA internal transcribed spacer (ITS 1 and ITS 2) and plastid rpoC1 intron sequences. High levels of nucleotide sequence variation preclude the use of the I...

journal_title：American journal of botany

authors： Downie S,Ramanath S,Katz-Downie D,Llanas E

更新日期：1998-04-01 00:00:00

abstract：:The hollow stem of Equisetum giganteum owes its mechanical stability to an outer ring of strengthening tissue, which provides stiffness and strength in the longitudinal direction, but also to an inner lining of turgid parenchyma, which lends resistance to local buckling. With a height >2.5 m isolated stems are mechani...

journal_title：American journal of botany

authors： Spatz H,Köhler L,Speck T

更新日期：1998-03-01 00:00:00

abstract：:Much of the ultraviolet-B radiation (UV-B) research on plants has concentrated on vegetative plant parts, and only a small fraction has dealt with the reproductive system. The present study analyzed pollen grains of 34 taxa germinated and grown under two levels of UV-B radiation (187 and 460 mW/m2) or no UV-B (control...

journal_title：American journal of botany

authors： Torabinejad J,Caldwell M,Flint S,Durham S

更新日期：1998-03-01 00:00:00

abstract：:In turnip mitochondria the cox2 gene is partially contained within a 2-kb (kilobase) direct repeat that is the site of homologous recombination events that generate subgenomic molecules. Because of its partial presence within the direct repeat, the turnip cox2 gene exists in four genomic contexts, two on the master ch...

journal_title：American journal of botany

authors： Dong F,Wilson K,Makaroff C

更新日期：1998-02-01 00:00:00

abstract：:Size, allometry, and mechanical design were measured for trees of three canopy species in a tropical rain forest in French Guiana. Mechanical design was expressed as the safety factor, using the elastic-stability model, and the wind resistance factor, using the constant-stress model. Changes with ontogeny were describ...

journal_title：American journal of botany

authors： Sterck F,Bongers F

更新日期：1998-02-01 00:00:00

abstract：:Five plant communities in Western Australia, as well as selected desert and Rocky Mountain species of the western USA, were surveyed to evaluate associations among leaf structure, orientational properties, and the sunlight exposure and precipitation characteristic of each community. Selected leaf structural features h...

journal_title：American journal of botany

authors： Smith W,Bell D,Shepherd K

更新日期：1998-01-01 00:00:00

abstract：:Epiphytes are ecologically important components of tropical forests worldwide and yet they have been underrepresented in studies of reproductive biology. Given the presumed ephemeral nature of their substrates, and the importance of dispersal and colonization, epiphytes might be expected to undergo substantial inbreed...

journal_title：American journal of botany

authors： Hooper E,Haufler C

更新日期：1997-12-01 00:00:00

abstract：:We assessed the effects of local environment on survival, growth, and development in six clones (genotypes) of Vallisneria americana grown at five sites in the Huron-Erie Corridor. Detrimental effects of local environment on plant performance (rate of clonal growth, leaf and root production, surface area of leaves and...

journal_title：American journal of botany

authors： Biernacki M,Lovett-Doust J

更新日期：1997-12-01 00:00:00

abstract：:It is generally thought that sedimenting plastids are responsible for gravity sensing in higher plants. We directly tested the model generated by the current statolith hypothesis that the gravity sensing that leads to gravitropism results from an interaction between the plastids and actin microfilaments. We find that ...

journal_title：American journal of botany

authors： Staves MP,Wayne R,Leopold AC

更新日期：1997-11-01 00:00:00

abstract：:We investigated the possible effect of recent (1927-1995) increases in the concentration of atmospheric CO2 on the stomatal densities of leaves of a wide range of tree, shrub, and herb species (N = 60) by making new measurements for comparison with corresponding data reported by E. J. Salisbury in 1927--a time when ic...

journal_title：American journal of botany

authors： Beerling D,Kelly C

更新日期：1997-11-01 00:00:00

abstract：:Inferring basal relationships among vascular plants poses a major challenge to plant systematists. The divergence events that describe these relationships occurred long ago and considerable homoplasy has since accrued for both molecular and morphological characters. A potential solution is to examine phylogenetic anal...

journal_title：American journal of botany

authors： Wolf P

更新日期：1997-10-01 00:00:00

abstract：:Atriplex prostrata Boucher, a facultative halophyte, exhibits significant reduction in height and biomass and in the width of the cortex and vascular tissue under saline conditions. Therefore, the goal of this investigation was to determine the effect of salinity on plant growth as well as on the patterns of lignifica...

journal_title：American journal of botany

authors： Wang L,Showalter A,Ungar I

更新日期：1997-09-01 00:00:00

abstract：:Floral organogenesis and development of the tropical legume trees Haematoxylum campechianum (logwood) and H. brasiletto (brazilwood) were studied using scanning electron microscopy. The aims were to compare ontogenies, and to elucidate the relationships of Haematoxylum with other genera of Caesalpinieae, the basal tri...

journal_title：American journal of botany

authors： Tucker S,Kantz K

更新日期：1997-08-01 00:00:00

abstract：:Contact forces are important in maintaining the twining habit of viny stems. A stem twining around a supporting pole puts itself into tension and uses a helical geometry to generate normal loads that are large relative to stem mass per unit length (Silk and Hubbard, Journal of Biomechanics 24(7):599-606, 1991). An ele...

journal_title：American journal of botany

authors： Matista A,Silk W

更新日期：1997-08-01 00:00:00

abstract：:The response of axillary buds to floral stimulus activity in stem pieces was examined in two near-isogenic cultivars of tobacco that differ in the recessive maryland mammoth (mm) allele, which confers short-day behavior. All axillary buds from day-neutral plants assayed on six-internode stem pieces made few nodes (les...

journal_title：American journal of botany

authors： Smith S,McDaniel C,Hartnett L

更新日期：1997-07-01 00:00:00

abstract：:Phylogenetic relationships of eight species of Saintpaulia H. Wendl., 19 species of Streptocarpus Lindl. (representing all major growth forms within the genus), and two outgroups (Haberlea rhodopensis Friv., Chirita spadiciformis W. T. Wang) were examined using comparative nucleotide sequences from the two internal tr...

journal_title：American journal of botany

authors： Moller M,Cronk Q

更新日期：1997-07-01 00:00:00

abstract：:Soybean partial-female-sterile mutant 1 (PS-1) was recovered from a gene-tagging study. The objectives were to study the inheritance, linkage, allelism, and certain aspects of the reproductive biology of the PS-1 mutant. For inheritance and linkage tests, PS-1 was crossed to flower color mutant Harosoy-w4 and to chlor...

journal_title：American journal of botany

authors： Pereira T,Lersten N,Palmer R

更新日期：1997-06-01 00:00:00

abstract：:The cell division pattern in the apical meristem of Psilotum nudum was examined using epi-illumination microscopy and a paraffin method. In the subterranean axis, about half of the derivative cells of the apical cell produce tetrahedral daughter apical cells by the first three or more oblique divisions. Roughly half o...

journal_title：American journal of botany

authors： Takiguchi Y,Imaichi R,Kato M

更新日期：1997-05-01 00:00:00

abstract：:Chloroplast DNA (cpDNA) restriction enzyme site analysis was used to test hypotheses of series and superseries affiliations of 76 taxa, representing 11 of the 13 South American series (material unavailable for two series) of wild potatoes (Solanum sect. Petota) recognized in the latest classification by Hawkes. The cl...

journal_title：American journal of botany

authors： Spooner D,Castillo R

更新日期：1997-05-01 00:00:00

abstract：:Chrysothamnus nauseosus (Asteraceae) is a complex polymorphic shrub species widely distributed in western North America. In a study of 86 populations belonging to 15 subspecies, achene mass varied among populations over a sevenfold range. Achene mass was closely correlated with capitulum size at the subspecies level, ...

journal_title：American journal of botany

authors： Meyer S

更新日期：1997-04-01 00:00:00

abstract：:The anther and ovule development of Camellia, Franklinia, and Schima (Theaceae, Camellioideae) were observed. The three genera share the following embryological traits: anther wall formation of basic type, tapetum of glandular type, walls of endothecial cells with secondary thickening, and production of pseudopollen g...

journal_title：American journal of botany

authors： Tsou C

更新日期：1997-03-01 00:00:00

abstract：:Tropical forest plants are known to be pollinated by a diverse array of animals. Here we report on the pollination of a woody climber species, Uvaria elmeri (Annonaceae), by cockroaches in a lowland mixed-dipterocarp forest in Sarawak, Malaysia. To the best of our knowledge, this is the first report of pollination by ...

journal_title：American journal of botany

authors： Nagamitsu T,Inoue T

更新日期：1997-02-01 00:00:00

abstract：:Nuclear and chloroplast DNA variation was assayed for two populations of Louisiana irises (Bayou Teche and Young's Coulee) that demonstrated extreme morphological variation and for a sample of the putative hybrid species, Iris nelsonii. The genetic markers examined in this analysis were diagnostic for either Iris fulv...

journal_title：American journal of botany

authors： Arnold ML

更新日期：1993-05-01 00:00:00

abstract：:Biparental inbreeding is thought to be a common feature of plant populations with restricted pollen dispersal. It is generally assumed that the inbreeding depression frequently observed to accompany self-fertilization can be extrapolated to the lesser degrees of consanguinity involved in biparental inbreeding, but thi...

journal_title：American journal of botany

authors： Heywood JS

更新日期：1993-05-01 00:00:00

abstract：:The effect of microgravity on cellulose synthesis using the model system of Acetobacter xylinum was the subject of recent investigations using The National Aeronautics and Space Administration's Reduced Gravity Laboratory, a modified KC-135 aircraft designed to produce 20 sec of microgravity during the top of a parabo...

journal_title：American journal of botany

authors： Brown RM Jr,Kudlicka K,Cousins SK,Nagy R

更新日期：1992-11-01 00:00:00

abstract：:Dispersal is an important life history component. Seed settling velocity may be a useful surrogate for the measurement of dispersal ability in wind-dispersed plants, particularly those whose seeds have plumose dispersal structures. I measured settling velocities on seeds of eight species of Asteraceae, including annua...

journal_title：American journal of botany

authors： Andersen MC

更新日期：1992-10-01 00:00:00

abstract：:To determine the effects of density, genotype, and their interaction on individual seed mass in Raphanus sativus L., we replicated maternal and paternal families of seed across two planting densities in an experimental garden. Seeds were produced by a nested breeding design performed in the greenhouse. Among garden-ra...

journal_title：American journal of botany

authors： Mazer SJ,Wolfe LM

更新日期：1992-10-01 00:00:00

abstract：:The pattern of DNA, RNA, and protein synthesis during lateral root initiation in Marsilea quadrifolia L. was monitored by autoradiography of incorporated of 3H-thymidine, 3H-uridine, and 3H-leucine, respectively. DNA synthesis was associated with the enlargement of the lateral root initial prior to its division. Con...

journal_title：American journal of botany

authors： Lin BL,Raghavan V

更新日期：1991-01-01 00:00:00