Search results for "botany"
showing 10 items of 4586 documents
Comparative analysis of leaf shape development inEschscholzia californicaand other Papaveraceae-Eschscholzioideae
2011
Dissected leaves in Papaveraceae-Eschscholzioideae have an architecture frequently encountered in the basal eudicot clade Ranunculales that could represent an ancestral condition for eudicots. Developmental morphology of foliage leaves was investigated using scanning electron microscopy and focusing on primordium formation activity (primary morphogenesis) at the leaf margin. Eschscholzia californica, E. lobii, and Hunnemannia fumariaefolia had a polyternate-acropetal mode of leaf dissection. Segment formation continued around the whole leaf blade periphery. Differences in mature leaf architecture was traced to variations in regional blastozone activity and duration. Epidermal cell size meas…
Orthotrichum Norrisii (Orthotrichaceae), A New Epiphytic Californian Moss
2008
Abstract A new Orthotrichum species, O. norrisii, is described from California. The new taxon is recognized by a unique combination of sporophytic characters: capsule narrowly cylindrical and not contracted below mouth when dry, exothecial bands narrow and formed by 2(–3) cell rows, peristome with eight pairs of exostome teeth and eight endostome segments, stomata cryptopore and located in the lower part of the urn, lid plane and rostrate and vaginula hairy. Widely distributed throughout California, the new taxon has been overlooked and confused with O. tenellum.
Pythium deliense causing severe damping-off of cucumber seedlings and its biological control by soil bacteria
1996
Abstract Pythium deliense Meurs was isolated from cucumber plant debris and was found to be highly pathogenic to cucumber seedlings, causing severe damping-off disease. The fungus however was completely inhibited by a soil bacterium SU-48.1. In vitro and in vivo studies reveal that the disease can be controlled by using this bacterium. The details of the parasitic fungus, the antagonism between the fungus and the bacteria, and the biological control of the disease, are described in this article.
Liming induced stimulation of the amino acid metabolism in mycorrhizal roots of Norway spruce (Picea abies [L.] Karst.)
1995
Localization and activity of three enzymes involved in the amino acid metabolism of ectomycorrhizas were investigated within an interdisciplinary experiment performed in a mature Norway spruce stand in Southern Germany (Hoglwald). The enzymes NAD-glutamate dehydrogenase and aspartate aminotransferase were present in root cells, whereas aminopeptidase was found in mycorrhizas of Norway spruce such as “Piceirhiza nigra” and those with the fungi Cenococcum geophilum, Elaphomyces sp., Russula ochroleuca and Tylospora sp. Mycorrhizas growing in the humus layer contained about double the amount of protein found in those taken from the upper mineral soil (0–5 cm).
Lag time for germination of Penicillium chrysogenum conidia is induced by temperature shifts.
2013
In the environment, fungal conidia are subject to transient conditions. In particular, temperature is varying according to day/night periods. All predictive models for germination assume that fungal spores can adapt instantaneously to changes of temperature. The only study that supports this assumption (Gougouli and Koutsoumanis, 2012, Modelling germination of fungal spores at constant and fluctuating temperature conditions. International Journal of Food Microbiology, 152: 153-161) was carried out on Penicillium expansum and Aspergillus niger conidia that, in most cases, already produced germ tubes. In contrast, the present study focuses on temperature shifts applied during the first stages…
The source of gibberellins in the parthenocarpic development of ovaries on topped pea plants.
1988
The role and source of gibberellins (GAs) involved in the development of parthenocarpic fruits of Pisum sativum L. has been investigated. Gibberellins applied to the leaf adjacent to an emasculated ovary induced parthenocarpic fruit development on intact plants. The application of gibberellic acid (GA3) had to be done within 1 d of anthesis to be fully effective and the response was concentration-dependent. Gibberellin A1 and GA3 worked equally well and GA20 was less efficient. [(3)H]Gibberellin A1 applied to the leaf accumulated in the ovary and the accumulation was related to the growth response. These experiments show that GA applied to the leaf in high enough concentration is translocat…
Micropropagation of adultLavandula dentataplants
1998
SummaryA protocol for in vitro propagation of adult Lavandula dentata plants has been achieved. Cultures were established by placing nodal segments on Murashige and Skoog medium containing BA, KIN, and NAA. Highest shoot multiplication rates were obtained when explants grown in the presence of 5.0 μM BA or 20 (JLM KIN were transferred to medium with 8.8 μM BA and 15% coconut milk. Multiplication efficiency through subcultures was significantly affected by the cytokinin concentration in the initial culture medium. Subculture reduced drastically the final number of shoots produced on nodal segments isolated from shoots grown in the presence of 2.0 μM BA or 40.0 μM KIN. Shoots were easily root…
Mtha1, a Plasma Membrane H+-ATPase Gene fromMedicago truncatula,Shows Arbuscule-Specific Induced Expression in Mycorrhizal Tissue
2002
: Transport processes between plant and fungal cells are key elements in arbuscular mycorrhiza (AM), where H+-ATPases are considered to be involved in active uptake of nutrients from the symbiotic interface. Genes encoding H+-ATPases were identified in the genome of Medicago truncatula and three cDNA fragments of the H+-ATPase gene family (Mtha1 - 3) were obtained by RT-PCR using RNA from M. truncatula mycorrhizal roots as template. While Mtha2 and Mtha3 appeared to be constitutively expressed in roots and unaffected by AM development, transcripts of Mtha1 could only be detected in AM tissues and not in controls. Further analyses by RT-PCR revealed that Mtha1 transcripts are not detectable …
The predatory mirid Dicyphus maroccanus as a new potential biological control agent in tomato crops
2014
The first record of the omnivorous predator Dicyphus maroccanus Wagner (Hemiptera: Miridae) inhabiting tomato crops in the Valencia region (East Coast of Spain) was in 2009. Since then, D. maroccanus has often been found preying on the eggs of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in this area. To evaluate this predator’s potential as a biological control agent, its life-history traits in the presence and absence of prey [(eggs of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)] on tomato plants were studied under laboratory conditions. Immature stages that preyed on eggs of E. kuehniella developed successfully. However, no nymph completed development on the plant without t…
Las hormigas (Hymenoptera, Formicidae) asociadas a pulgones (Hemiptera, Aphididae) en la provincia de Valencia
2002
Twenty-six species of ants associated with aphids, belonging to twelve genera, are collected. Three subfamilies are identified, being the Formicinae the more represented about number of samples, genera and species. On the other hand, <i>Lasius niger</i> has been the species that is found with a more number of aphids (fifty eight species), and it seems to be the ant with a more capacity to establish associations with the different species of aphids. 224 different associations between the ants and the aphids are established and 164 of them are not recorded in the bibliography consulted for Spain.<br><br>Se han recogido veintiséis especies de hormigas asociadas a pulgon…