Étude ultrastructurale des coiffes des racines de chêne (Quercus robur). I. Les pivots

1982 ◽  
Vol 60 (5) ◽  
pp. 620-629 ◽  
Author(s):  
Jean Dexheimer ◽  
Jean Muller ◽  
Arthur Riedacker
Keyword(s):  
Quercus Robur ◽  
Room Temperature ◽  
Vertical Plane ◽  
Woody Species ◽  
Herbaceous Species ◽  
Meristematic Zone ◽  
Root Curvature ◽  
Cell Layers ◽  
Inosine Diphosphatase ◽  
Vacuolar System

Three zones may be distinguished in rootcaps of orthogeotropic taproots of oak seedlings.(1) The meristematic zone: cells have no distinctive characteristics except that they always have small rounded vacuoles.(2) The statocytes have amyloplastids accumulating in the lower cell portion. The nucleus is near the upper end. Unlike the herbaceous species studied, these cells have large central vacuoles. This may be a characteristic of woody species. This hypothesis is discussed.After a 90 or 135° rotation in a vertical plane, amyloplastids become progressively concentrated in the new lower end of the statocyte. Orientation of the endoplasmic reticulum also changes, and the vacuolar system is reorganized. At room temperature root curvature begins to appear more than 2 h after the rotation.(3) The outside cell layers are composed of mucilage secreting cells with dictyosomes producing large vesicles containing polysaccharides. These accumulate in the periplasmic area. A strong inosine diphosphatase activity is shown in the vesicles.

Influence of Sulfonylurea and Other Herbicides on Selected Woody and Herbaceous Species

Weed Science ◽  
1990 ◽  
Vol 38 (3) ◽  
pp. 249-255 ◽  
Author(s):  
Robert E. Meyer ◽  
Rodney W. Bovey
Keyword(s):  
Plant Cover ◽  
Woody Species ◽  
Herbaceous Plant ◽  
Herbaceous Species ◽  
Grass Cover ◽  
Weed Cover ◽  
Broadleaf Species ◽  
Honey Mesquite

Chlorsulfuron and metsulfuron were effective on Texas whitebrush, killing 70 to 75% of the plants at 0.28 kg ai ha, marginally effective on Macartney rose, killing 15 to 43% of the plants at 1.12 kg ha, but ineffective on honey mesquite and huisache, killing no more than 10% of the plants at 1.12 kg ha. Sulfometuron was ineffective on all woody species at 1.12 kg ai ha. Clopyralid and picloram were effective, killing 70 to 92% of the huisache at 2.24 kg ae ha. Tebuthiuron killed 72% of the Texas whitebrush at 1.12 kg ai ha. Sulfometuron generally reduced herbaceous plant cover the year of application. Chlorsulfuron and metsulfuron often resulted in increased grass cover the year of application. Most herbicides reduced broadleaf weeds the year of application. Woolly croton often was the first prominent broadleaf species to return to areas treated with clopyralid and sulfometuron. Few differences occurred among herbicides in herbaceous weed cover the year following treatment.

Phylogeny and Character Evolution in Nierembergia (Solanaceae): Molecular, Morphological, and Cytogenetic Evidence

2009 ◽  
Vol 34 (1) ◽  
pp. 198-206 ◽  
Author(s):  
Jennifer A. Tate ◽  
M. Cristina Acosta ◽  
Joshua McDill ◽  
Eduardo A. Moscone ◽  
Beryl B. Simpson ◽  
...  
Keyword(s):  
Woody Species ◽  
Herbaceous Species ◽  
Chromosome Counts ◽  
Nucleolar Organizing Regions ◽  
Molecular Phylogenetic ◽  
Cytogenetic Evidence ◽  
Nuclear Its ◽  
Phylogenetic Hypotheses ◽  
Genus One ◽  
Petunia Axillaris

Nierembergia (Solanaceae) contains 21 species found primarily in South America, with one species occurring disjunctly in Mexico. Among other features, a pollination system not found elsewhere in the Solanaceae typifies this genus. In most species, nectaries are absent, but oil-producing elaiophores are present on the corolla limb and these attract oil-collecting bees. Molecular phylogenetic hypotheses based on nuclear ITS and chloroplast rpl16 intron data support the monophyly of Nierembergia, which is sister to a clade composed of Bouchetia plus Hunzikeria. The data reconstruct two clades within the genus: one composed primarily of herbaceous species with broad stigmas and the second containing woody species with crescent-shaped stigmas. Morphological homoplasy is frequent among the species of the herbaceous clade, while the woody clade is morphologically cohesive. Chromosome counts are confirmed and karyotype features are given for 13 Nierembergia species (including six varieties) and for Bouchetia anomala, Leptoglossis linifolia, and Petunia axillaris. The two clades are also supported by karyotypic features: one has asymmetrical karyotypes, small chromosomes, and two chromosome pairs with nucleolar organizing regions (NOR) and the other has symmetrical karyotypes, large chromosomes, and only one NOR.

Expérimentation sur la compétition interspécifique par élimination sélective d'espèces forestières

1983 ◽  
Vol 13 (3) ◽  
pp. 522-532 ◽  
Author(s):  
P. Bellefleur ◽  
Y. Pétillon
Keyword(s):  
Experimental Study ◽  
Sugar Maple ◽  
Woody Species ◽  
Growth Increment ◽  
Herbaceous Species ◽  
Height Increment ◽  
Yellow Birch ◽  
Soil Temperatures

We conducted an experimental study of competition for water, heat, and space between woody species and herbaceous species by selective exclusion of a few species in a sugar maple stand. We found large differences in diameter and height increment for all three species under investigation: sugar maple, yellow birch, and beech. Large differences were also found in soil temperatures to a depth of 30 cm which were correlated with cover and growth increment. We concluded that there is indeed a severe competition between woody and herbaceous species for both heat and space.

scholarly journals How small and constrained is the genome size of angiosperm woody species

2015 ◽  
Vol 64 (1-6) ◽  
pp. 20-32 ◽  
Author(s):  
Deepak Ohri
Keyword(s):  
Genome Size ◽  
Cell Size ◽  
Large Population ◽  
Size Variation ◽  
Woody Species ◽  
Herbaceous Species ◽  
Wood Fibers ◽  
Genome Size Variation ◽  
Woody Habit ◽  
Taxonomic Groups

AbstractAngiosperm hardwood species are generally considered to show an average smaller genome size with a narrow range of variation than their herbaceous counterparts. Various explanations pertaining to limitations of cell size exerted by wood fibers, the requirement of smaller stomata, longer generation time, large population size, etc., have been put forward to account for their small and constrained genome size. Yet studies done in the past several years show that genomically as well as evolutionarily, hardwoods are as diverse and active as their herbaceous counterparts. This is entirely supported by the presence of well developed inter and intraspecific polyploid series and natural triploidy in many genera. Polyploidy, in some instances has been shown to confer adaptability to arid and salt stress conditions and in colonization of new areas. Moreover, hardwoods also show reasonable amenability to the induced polyploidy which abruptly changes the balance between nuclear and cell size. Polyploidy has been induced in many hardwoods to restore fertility in interspecific hybrids and for the production of triploids.Furthermore, some cases studied show that genome size variation in hardwoods can be as variable as that of herbaceous species. Genome size has been shown to vary remarkably both at homoploid level as well as by polyploidy in certain genera. In the same way, the genome size is not correlated with the habit in certain groups having both herbaceous and woody taxa. This point is further proved by the presence of secondary and insular woody habit in certain cases where either the transition to woodiness is not followed by any diminution in the genome size, or the genome size of insular woody species may be even more than that of the congeneric herbaceous species. This shows that woody habit does not by itself put any constraints on the genome size either at homoploid or at polyploidy levels. The genome size in fact, not only varies significantly in many congeneric woody species but also may not show any correlation with the habit when woody and herbaceous species are compared in some narrow taxonomic groups studied.

Light and transmission electron microscopy of English oak ectomycorrhizal short roots

1984 ◽  
Vol 62 (7) ◽  
pp. 1327-1335 ◽  
Author(s):  
H. H. Edwards ◽  
R. V. Gessner
Keyword(s):  
Electron Microscopy ◽  
Cell Walls ◽  
Quercus Robur ◽  
Lipid Droplets ◽  
Apical Meristem ◽  
Fungal Symbiont ◽  
Host Root ◽  
Transmission Electron ◽  
Cell Layers ◽  
English Oak

The incorporation of caffeine in standard transmission electron microscope fixation procedures has allowed good preservation and embedment of ectomycorrhizal short roots of English oak (Quercus robur L.). In the mantle the most conspicuous structures are cystidia which radiate outwards from the surface. These conically shaped cells have knobs at their tips and thickened cell walls. The cystidia and other outer mantle cells contain many cytoplasmic constituents, whereas the inner mantle cells are nearly devoid of cytoplasm. The mantle cells are held together by an intercellular slime network. The Hartig net cells are filled with cytoplasm and contain numerous lipid droplets. Typical dolipore septa separate the cells; however, these cells have irregularly branched shapes. The host root tissue appears little altered by the presence of the fungal symbiont. However, the root cap consists of only a few cell layers. The apical meristem is functional as evidenced by the presence of newly divided cells and microtubules lining enlarging cells.

scholarly journals Short Communication: Floristic composition and relationships between plant species abundance and soil properties in common hazel (Corylus avellana) mountainous forest of northern Iran

2018 ◽  
Vol 19 (5) ◽  
pp. 1835-1841
Author(s):  
GHADER POURRAHMATI ◽  
ASADOLLAH MATAJI ◽  
HASSAN POURBABAEI ◽  
ALI SALEHI
Keyword(s):  
Soil Properties ◽  
Plant Species ◽  
Short Communication ◽  
Species Abundance ◽  
Floristic Composition ◽  
Woody Species ◽  
Corylus Avellana ◽  
Herbaceous Species ◽  
Northern Iran ◽  
Total N

Pourrahmati G, Mataji A, Pourbabaei H, Salehi A. 2018. Short Communication: Floristic composition and relationships between plant species abundance and soil properties in common hazel (Corylus avellana) mountainous forest of northern Iran. Biodiversitas 19: 1835-1841. Mountainous forests are valuable terrestrial ecosystems because of their useful services for the human being. Here, we explored the floristic composition and the relationships between plant species abundance distribution and soil physical and chemical properties in common hazel (Corylus avellana L.) in the mountainous forest of northern Iran. Within the forest stand, 30 quadrats (20 m × 20 m and 1 m × 1 m for woody and herbaceous species, respectively) were selectively sampled along an altitudinal range from 1300 m to 1800 m a.s.l. to assess plant species composition and abundance, and soil samples were taken to perform chemical and physical analyses. The results showed that a total of 43 herbaceous and 15 woody species belonging to 23 and 8 families were identified. The abundance of herbaceous species was significantly correlated with soil properties (pH and total N). Furthermore, the abundance of woody species had a non-significant correlation with soil properties.

Compétition pour le rayonnement solaire en début de succession secondaire dans une érablière à bouleau jaune et hêtre

1983 ◽  
Vol 13 (3) ◽  
pp. 514-521 ◽  
Author(s):  
P. Bellefleur ◽  
G. LaRocque
Keyword(s):  
Solar Radiation ◽  
Sugar Maple ◽  
Woody Species ◽  
Herbaceous Species ◽  
Yellow Birch ◽  
Radiation Interception ◽  
Clear Cutting ◽  
Surface Soil Temperature ◽  
Succession Secondaire ◽  
Rayonnement Solaire

We demonstrate that sugar maple (Acersaccharum Marsh.), yellow birch (Betulaalleghaniensis Britton), and beech (Fagusgrandifolia Ehrh.) compete for solar radiation against other woody species (noncommercial) and herbaceous species, following clear-cutting. The experiment was carried out at the Duchesnay Forest Station (Quebec, Canada) in a sugar maple – yellow birch – beech community and consisted of one control and two treatments: (1) elimination of noncommercial woody species and (2) elimination of noncommercial woody species and herbaceous species. The graph of solar radiation interception versus cover indicates that crown overlapping does not contribute significantly to any increase in solar radiation interception. Surface soil temperature is strongly linked to the decrease in solar radiation due to its interception by plants.

Ultraviolet reflectance from tamarack (Larixlaricina (DuRoi) K. Koch) foliage

1982 ◽  
Vol 12 (4) ◽  
pp. 1010-1012
Author(s):  
R. C. Feeney ◽  
P. E. Marshall ◽  
C. E. Olson Jr.
Keyword(s):  
Ultraviolet Light ◽  
Woody Species ◽  
Local Area ◽  
Herbaceous Species ◽  
Multispectral Images ◽  
Cuticular Waxes ◽  
Ultraviolet Reflectance

Examination of aerial, multispectral scanner images indicated that Larixlaricina (DuRoi) K. Koch foliage was much more reflective of ultraviolet light than was foliage of other woody species in the local area. This was confirmed in spectrophotometric studies. Young L. laricina needles reflected about 10% of incident ultraviolet light whereas foliage of 10 other woody species and 2 understory herbaceous species reflected less than 6%. The higher reflectivity of L. laricina needles was lost if cuticular waxes were removed from young needles or if needles were exposed to weathering for more than 2 months. The role of ultraviolet reflectivity is unclear, but the phenomenon may be a useful tool to identify L. laricina in multispectral images.

Cytogenetic analyses of intersectional hybrids between Parthenium argentatum and Parthenium confertum

Genome ◽  
1989 ◽  
Vol 32 (1) ◽  
pp. 134-140 ◽  
Author(s):  
A. Hashemi ◽  
A. Estilai ◽  
J. G. Waines
Keyword(s):  
Natural Rubber ◽  
Growth Habit ◽  
Backcross Progeny ◽  
Woody Species ◽  
Herbaceous Species ◽  
Parthenium Argentatum ◽  
Preferential Pairing ◽  
Homologous Chromosomes ◽  
Multivalent Formation ◽  
Cytogenetic Analyses

Induced tetraploid guayule (Parthenium argentatum Gray, a rubber-producing and woody species of section Parthenicaeta) was crossed to P. confertum var. lyratum Gray, a herbaceous species of section Argyrocheta. Hybrids were obtained when guayule was used as female. Like their diploid progenitors, induced tetraploids were sexual and self-incompatible. At meiosis, they averaged 0.30 I, 29.63 II, 0.12 III, and 3.02 IV. Parthenium confertum had 69 chromosomes and was apomictic. At meiosis, it averaged 1.00 I, 32.98 II, and 0.51 IV. Hybrids received 36 chromosomes from guayule and 34 chromosomes from P. confertum. At meiosis, they averaged 0.52 I, 33.44 II, 0.20 III, and 0.50 IV. F1 plants behaved like an amphidiploid in which homologous chromosomes of guayule genome paired with each other and homologous chromosomes of P. confertum genome also paired preferentially. Chromosome association in the hybrids indicated that P. confertum parent may be a tetraploid with suppressed multivalent formation. Although hybrids were partially fertile and produced backcross progeny, the transfer of desirable traits (rapid growth and herbaceous growth habit) from P. confertum into guayule will depend on elimination of preferential pairing in the hybrids.Key words: guayule, natural rubber, meiosis, chromosome pairing.

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