Abstract:
:Koch et al. (Nature 428: 851-854) measured various parameters that were thought to limit the height of Sequoia sempervirens from northern California and concluded that the maximum height for this species is 122-130 m because within this range: (1) Irreversible embolism formation was proposed to occur when the xylem pressure was less than -1.9 MPa. (2) The leaf mass to area ratio exponentially approached 833 g×m(-2). (3) The discrimination against (13)CO(2) exponentially approached -20. (4) Light-saturated photosynthesis per unit leaf mass decreased to zero, indicating no net gain in leaf biomass. These conclusions are questioned here by reassessing the assumed limits to the biophysical parameters and by reexamining the proposed linear and exponential relationships between these parameters and tree height. It is concluded that: (1) Embolism repair mechanisms could have occurred at -2.7 MPa. (2) The leaf mass to area ratio could be a result of, rather than a determinant of, the large differential between cellular turgor and the xylem pressure. (3) The discrimination against (13)CO(2) may show two populations of foliage with apparent linear relationships with height rather than one exponential relationship. (4) The light-saturated photosynthesis per unit leaf mass as a measure of biomass investment in leaf expansion excludes investment in branch and trunk wood. As a result, tree height may be limited by a long-term balance between dieback and continued growth.
journal_name
Am J Botjournal_title
American journal of botanyauthors
Netting AGdoi
10.3732/ajb.0800144subject
Has Abstractpub_date
2009-02-01 00:00:00pages
542-4issue
2eissn
0002-9122issn
1537-2197pii
96/2/542journal_volume
96pub_type
杂志文章abstract::Biogeographical studies of lichens used to be complicated because of the large distribution ranges of many species. Molecular systematics has revitalized lichen biogeography by improving species delimitation and providing better information about species range limitations. This study focuses on the major clade of trop...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900140
更新日期:2010-04-01 00:00:00
abstract:PREMISE OF THE STUDY:Permineralization provides the most faithful known mode of three-dimensional preservation of the morphology and cellular anatomy of fossil plants. Standard optical microscopic documentation of such structures can provide only an approximation of their true three-dimensional form and is incapable of...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1300027
更新日期:2013-08-01 00:00:00
abstract:PREMISE OF THE STUDY:To enhance our knowledge of the diversity of microalgae, a phycological survey of the Canary Islands (Spain) was undertaken. Here we report the discovery of a (semi)terrestrial green filamentous alga isolated from a steep volcanic canyon on La Palma. This alga is continually exposed to changing wea...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1500199
更新日期:2015-09-01 00:00:00
abstract:PREMISE:Although polyploidy has been studied since the early 1900s, fundamental aspects of polyploid ecology and evolution remain unexplored. In particular, surprisingly little is known about how newly formed polyploids (neopolyploids) become demographically established. Models predict that most polyploids should go ex...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1466
更新日期:2020-05-01 00:00:00
abstract::The biological nature of some symbioses is unclear because it is often not easy to discern whether the symbionts obtain any benefits from the association. Mastodia tessellata, a symbiosis between a leafy green alga and a fungus of uncertain phylogenetic position, is among the most investigated, controversial, and poor...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900323
更新日期:2010-05-01 00:00:00
abstract::Eight ecosystems that were present in the Cretaceous about 100 Ma (million years ago) in the New World eventually developed into the 12 recognized for the modern Earth. Among the forcing mechanisms that drove biotic change during this interval was a decline in global temperatures toward the end of the Cretaceous, augm...
journal_title:American journal of botany
pub_type: 杂志文章,评审
doi:10.3732/ajb.1000353
更新日期:2011-03-01 00:00:00
abstract:PREMISE OF THE STUDY:Drosera peltata var. nipponica, an element of the East Asia warm-temperate vegetation, and D. rotundifolia, a widely distributed boreal species, reach one of their northernmost and southernmost limits, respectively, on the Korean Peninsula. Because the Last Glacial Maximum (LGM)-Holocene dynamics o...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1200486
更新日期:2013-11-01 00:00:00
abstract:PREMISE OF THE STUDY:Giant cacti species possess long cylindrical stems that store massive amounts of water and other resources to draw on for photosynthesis, growth, and reproduction during hot and dry conditions. Across all giant cacti taxa, stem photosynthetic surface area to volume ratio (S:V) varies by several fol...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1166
更新日期:2018-10-01 00:00:00
abstract::Bamboo is considered useful for controlling landslides, but we observed numerous shallow-slope failures in forests of big node bamboo (Phyllostachys nidularia) in Sichuan, China. Therefore, we inventoried landslide occurrence and vegetation type along one valley. To quantify bamboo root anchorage, we performed uprooti...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.94.7.1129
更新日期:2007-07-01 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
pub_type: 杂志文章
doi:
更新日期:1998-08-01 00:00:00
abstract::Many foliar pathogens require free water to germinate; therefore, disease pressure should favor plants that are able to repel water. For a suite of 18 sympatric clover species (Trifolium and Medicago, Fabaceae), we evaluated leaf traits affecting leaf wetness and susceptibility to infection by the fungal pathogen Stem...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.90.6.857
更新日期:2003-06-01 00:00:00
abstract:PREMISE:The Eocene-Oligocene transition (EOT; 34-33 Ma) was marked by global cooling and increased seasonality and aridity, leading to a shift in North American floras from subtropical forests to deciduous hardwood forests similar to today. This shift is well documented taxonomically and biogeographically, but its ecol...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1580
更新日期:2020-12-01 00:00:00
abstract::New individuals in clonal populations arise through the recruitment of sexual or clonal offspring. The predominance of one type of regeneration over the other has been correlated with different selective environmental pressures. We compared the reproductive mode (sexual through seeds and vegetative through plantlets o...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.93.4.505
更新日期:2006-04-01 00:00:00
abstract::Long-distance transplantation of seed material as done in restoration programs has raised concerns about the risks associated with the introduction of maladapted genotypes that may hybridize with neighboring native conspecifics and decrease local population fitness (outbreeding depression). We studied the consequences...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900103
更新日期:2010-01-01 00:00:00
abstract:UNLABELLED: PREMISE OF THE STUDY:An anatomical examination of dry and fleshy fruits within the Solanaceae was carried out to identify comparable stages throughout development as well as features exclusive to each type of fruit. We studied fruit development of Nicotiana and Petunia, which have the plesiomorphic capsula...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1100097
更新日期:2011-09-01 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
pub_type: 杂志文章
doi:
更新日期:1997-08-01 00:00:00
abstract::Extreme preformation, the initiation of leaves or inflorescences more than 1 yr before maturation and function, is common in arctic and alpine habitats. This extended pattern of development provides a potential means to alleviate an apparent asynchrony between carbon supplied by photosynthesis in the summer and carbon...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.90.9.1313
更新日期:2003-09-01 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
pub_type: 杂志文章
doi:10.1002/j.1537-2197.1993.tb13843.x
更新日期:1993-05-01 00:00:00
abstract:PREMISE OF THE STUDY:Pollen dispersal is a key process that influences ecological and evolutionary dynamics of plant populations by facilitating sexual reproduction and gene flow. Habitat loss and fragmentation have the potential to reduce pollen dispersal within and among habitat patches. We assessed aquatic pollen di...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1031
更新日期:2018-02-01 00:00:00
abstract::Gelatinous fibers (G-fibers) are the active component of tension wood. G-fibers are unlike traditional fiber cells in that they possess a thick, nonlignified gelatinous layer (G-layer) internal to the normal secondary cell wall layers. For the past several decades, the G-layer has generally been presumed to be compose...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.2007368
更新日期:2008-06-01 00:00:00
abstract:PREMISE OF THE STUDY:Both polyploidy and shifts in floral color have marked angiosperm evolution. Here, we investigate the biochemical basis of the novel and diverse floral phenotypes seen in allopolyploids in Nicotiana (Solanaceae) and examine the extent to which the merging of distinct genomes alters flavonoid pigmen...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1600350
更新日期:2017-01-01 00:00:00
abstract:PREMISE:Light is critical in the ability of plants to accumulate chlorophyll. When exposed to far-red (FR) light and then grown in white light in the absence of sucrose, wild-type seedlings fail to green in a response known as the FR block of greening (BOG). This response is controlled by phytochrome A through repressi...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/ajb2.1423
更新日期:2020-02-01 00:00:00
abstract::When more pollen is present on stigmas than needed to fertilize all ovules, selection among pollen grains may occur due to effects of both pollen donors and maternal plants. We asked whether increasing plant age and flower age, two changes in maternal condition, altered the pattern of seed paternity after mixed pollin...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.94.3.409
更新日期:2007-03-01 00:00:00
abstract::Trichomanes intricatum, the sporophyte-less filmy fern of the eastern United States, has been considered to be a species whose sporophyte generation has become extinct or is possibly still present among the many species of Trichomanes s.l. in the new world tropics but unable to grow in a temperate climate. A close rel...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0800122
更新日期:2008-12-01 00:00:00
abstract::Intensified ultraviolet-B radiation or UV-B (wavelengths between 280 and 320 nm) can delay flowering and diminish lifetime flower production in a few plants. Here we studied the effects of enhanced UV-B on floral traits crucial to pollination and pollinator reproduction. We observed simultaneous flowering responses of...
journal_title:American journal of botany
pub_type: 杂志文章
doi:
更新日期:1999-01-01 00:00:00
abstract:PREMISE OF THE STUDY:Documented fossil floras in the neotropics are sparse, yet their records provide evidence on the spatial and temporal occurrence of taxa, allowing for testing of biogeographical and diversification scenarios on individual lineages. A new fossil Piper from the Late Cretaceous of Colombia is describe...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1400427
更新日期:2015-02-01 00:00:00
abstract::The fresh weights of suspension cultures of pear (Pyrus communis) and quince (Cydonia oblonga) increased exponentially for 30 to 40 days after subculturing. Transferring pear cultures to media in which quince cultures had grown for 10 days resulted in a 70% inhibition of callus growth. Transferring quince cultures to ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.1002/j.1537-2197.1986.tb09673.x
更新日期:1986-01-01 00:00:00
abstract:PREMISE OF THE STUDY:Microsatellite markers were developed for the dove tree, Davidia involucrata (Cornaceae), a Tertiary relict currently endemic to China, to investigate its population genetics and phylogeography. METHODS AND RESULTS:Using the Fast Isolation by AFLP of Sequences Containing repeats (FIASCO) protocol,...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1100414
更新日期:2012-03-01 00:00:00
abstract:PREMISE OF THE STUDY:Understanding the flexibility of monocot genomes requires a phylogenetic framework, which so far is available for few of the ca. 2800 genera. Here we use a molecular tree for the South American genus Alstroemeria to place karyological information, including fluorescent in situ hybridization (FISH) ...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.1200104
更新日期:2012-09-01 00:00:00
abstract::Darwin's research on botany and plant physiology was a landmark attempt to integrate plant movements into a biological perspective of behavior. Since antiquity, people have sought to explain plant movements via mechanical or physiological forces, and yet they also constructed analogies between plant and animal behavio...
journal_title:American journal of botany
pub_type: 杂志文章
doi:10.3732/ajb.0900220
更新日期:2009-12-01 00:00:00