The Leaf Anatomy of Leptospermum Forst. (Myrtaceae)

1980 ◽  
Vol 28 (1) ◽  
pp. 77 ◽  
Author(s):  
CT Johnson
Keyword(s):  
Leaf Anatomy ◽  
Water Availability ◽  
Anatomical Variation ◽  
Species Level ◽  
Individual Species ◽  
Stomatal Development ◽  
Ecological Data ◽  
Anatomical Characters ◽  
Character Complexes ◽  
The Individual

The leaf anatomy of 40 species of Leptospermum Forst. (Myrtaceae) is described in detail. The genus shows a fairly constant, typically myrtaceous leaf structure with isobilateral mesophyll and the presence of schizogenous oil cavities as constant characters. Variation occurs in stomatal type, sculpturing of the cuticle, persistence of the indumentum, and structure of the oil cavities. Both perigenous and mesoperigenous types of stomatal development have been observed. A number of characters show a considerable variation below the species level. The pattern of anatomical variation does not support Bentham's subdivision of the genus into three sections. Alternative subdivisions cannot be proposed on account of considerable overlap of the character complexes of the individual species. In some cases it is, however, possible to suggest mutual affinity (e. g. between L. laevigatum and L. coriaceum) on the basis of leaf anatomy. A comparison of the available ecological data with anatomical characters supports some of the generalized trends for increased xeromorphy with water availability. On the whole, however, all species of Leptospermum, including the mesic ones, show a rather xeromorphic leaf anatomy.

Stability and Variability in Competitive Communities

Science ◽  
1999 ◽  
Vol 286 (5439) ◽  
pp. 542-544 ◽  
Author(s):  
A. R. Ives ◽  
K. Gross ◽  
J. L. Klug
Keyword(s):  
Species Level ◽  
Community Level ◽  
Competitive Interactions ◽  
Species Number ◽  
Individual Species ◽  
Community Stability ◽  
Environmental Fluctuations ◽  
The Individual ◽  
Theoretical Analyses

Long-term variability in the abundance of populations depends on the sensitivity of species to environmental fluctuations and the amplification of environmental fluctuations by interactions among species. Although competitive interactions and species number may have diverse effects on variability measured at the individual species level, a combination of theoretical analyses shows that these factors have no effect on variability measured at the community level. Therefore, biodiversity may increase community stability by promoting diversity among species in their responses to environmental fluctuations, but increasing the number and strength of competitive interactions has little effect.

scholarly journals Retrieval of Mangrove Aboveground Biomass at the Individual Species Level with WorldView-2 Images

2015 ◽  
Vol 7 (9) ◽  
pp. 12192-12214 ◽  
Author(s):  
Yuanhui Zhu ◽  
Kai Liu ◽  
Lin Liu ◽  
Shugong Wang ◽  
Hongxing Liu
Keyword(s):  
Aboveground Biomass ◽  
Species Level ◽  
Individual Species ◽  
The Individual

scholarly journals Gene Sequencing and Phylogenetic Analysis: Powerful Tools for an Improved Diagnosis of Fish Mycobacteriosis Caused by Mycobacterium fortuitum Group Members

2021 ◽  
Vol 9 (4) ◽  
pp. 797
Author(s):  
Davide Mugetti ◽  
Mattia Tomasoni ◽  
Paolo Pastorino ◽  
Giuseppe Esposito ◽  
Vasco Menconi ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Gene Sequencing ◽  
Diagnostic Techniques ◽  
Individual Species ◽  
Identification System ◽  
Mycobacterium Fortuitum ◽  
Biochemical Tests ◽  
Species Determination ◽  
Gene Encoding ◽  
The Individual

The Mycobacterium fortuitum group (MFG) consists of about 15 species of fast-growing nontuberculous mycobacteria (NTM). These globally distributed microorganisms can cause diseases in humans and animals, especially fish. The increase in the number of species belonging to MFG and the diagnostic techniques panel do not allow to clarify their real clinical significance. In this study, biomolecular techniques were adopted for species determination of 130 isolates derived from fish initially identified through biochemical tests as NTM belonging to MFG. Specifically, gene sequencing and phylogenetic analysis were used based on a fragment of the gene encoding the 65 KDa heat shock protein (hsp65). The analyzes made it possible to confirm that all the isolates belong to MFG, allowing to identify the strains at species level. Phylogenetic analysis substantially confirmed what was obtained by gene sequencing, except for six strains; this is probably due to the sequences present in NCBI database. Although the methodology used cannot represent a univocal identification system, this study has allowed us to evaluate its effectiveness as regards the species of MFG. Future studies will be necessary to apply these methods with other gene fragments and to clarify the real pathogenic significance of the individual species of this group of microorganisms.

scholarly journals Holocene changes in African vegetation: tradeoff between climate and water availability

2014 ◽  
Vol 10 (2) ◽  
pp. 681-686 ◽  
Author(s):  
C. Hély ◽  
A.-M. Lézine ◽  
APD contributors
Keyword(s):  
West Africa ◽  
Water Availability ◽  
Regional Scale ◽  
Plant Distribution ◽  
Climate Conditions ◽  
Tropical Plants ◽  
Plant Migration ◽  
Spatio Temporal ◽  
The Individual ◽  
Instrumental Records

Abstract. Although past climate change is well documented in West Africa through instrumental records, modeling activities, and paleo-data, little is known about regional-scale ecosystem vulnerability and long-term impacts of climate on plant distribution and biodiversity. Here we use paleohydrological and paleobotanical data to discuss the relation between available surface water, monsoon rainfall and vegetation distribution in West Africa during the Holocene. The individual patterns of plant migration or community shifts in latitude are explained by differences among tolerance limits of species to rainfall amount and seasonality. Using the probability density function methodology, we show here that the widespread development of lakes, wetlands and rivers at the time of the "Green Sahara" played an additional role in forming a network of topographically defined water availability, allowing for tropical plants to migrate north from 15 to 24° N (reached ca. 9 cal ka BP). The analysis of the spatio–temporal changes in biodiversity, through both pollen occurrence and richness, shows that the core of the tropical rainbelt associated with the Intertropical Convergence Zone was centered at 15–20° N during the early Holocene wet period, with comparatively drier/more seasonal climate conditions south of 15° N.

Taxonomic application of macro and micro morphological characters of seeds in Astragalus L. (Galegeae, Fabaceae) in India

Phytotaxa ◽  
2021 ◽  
Vol 502 (2) ◽  
pp. 191-207
Author(s):  
SHIVANI KASHYAP ◽  
CHANDAN KUMAR SAHU ◽  
ROHIT KUMAR VERMA ◽  
LAL BABU CHAUDHARY
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Seed Coat ◽  
Morphological Plasticity ◽  
Morphological Characters ◽  
Individual Species ◽  
Large Size ◽  
The Individual ◽  
Scanning Electron

Due to large size and enormous morphological plasticity, the taxonomy of the genus Astragalus is very complex and challenging. The identification and grouping of species chiefly based on macromorphological characters become sometimes difficult in the genus. In the present study, the micromorphology of the seeds of 30 species belonging to 14 sections of Astragalus from India has been examined applying scanning electron microscopy (SEM) along with light microscopy (LM) to evaluate their role in identification and classification. Attention was paid to colour, shape, size and surface of seeds. The overall size of the seeds ranges from 1.5–3.2 × 0.8–2.2 mm. The shape of the seeds is cordiform, deltoid, mitiform, orbicular, ovoid and reniform. The colour of seeds varies from brown to blackish-brown to black. Papillose, reticulate, ribbed, rugulate and stellate patterns were observed on the seed coat surface (spermoderm) among different species. The study reveals that the seed coat ornamentations have evolved differently among species and do not support the subgeneric and sectional divisions of the genus. However, they add an additional feature to the individual species, which may help in identification in combination with other macro-morphological features.

Larval and post-larval stages of fishes recorded from the plankton of Galway Bay, 1972–73

1976 ◽  
Vol 56 (1) ◽  
pp. 197-211 ◽  
Author(s):  
Julie M. Fives ◽  
F. I. O'Brien
Keyword(s):  
Copepod Species ◽  
Individual Species ◽  
Larval Stages ◽  
Percentage Occurrence ◽  
Bay Area ◽  
The Individual ◽  
Recorded Occurrence

The Galway Bay area was sampled quantitatively for plankton during 1972–3. The larvae and/or post-larvae of 67 species of fish were identified from the plankton. The recorded occurrence per m3 and the percentage occurrence of the individual species is presented and discussed, and reference is made to the concurrent occurrence of various chaetognath species and copepod species. The results of previous investigations of the plankton of the Galway Bay area are mentioned.

scholarly journals Species interactions in three Lemnaceae species growing along a gradient of zinc pollution

2021 ◽  
Author(s):  
Lorena Lanthemann ◽  
Sofia van Moorsel
Keyword(s):  
Growth Rates ◽  
Species Interactions ◽  
Metal Removal ◽  
Lemna Minor ◽  
Polluted Water ◽  
Future Research ◽  
Individual Species ◽  
High Tolerance ◽  
Species Mixture ◽  
The Individual

Duckweeds (Lemnaceae) are increasingly studied for their potential for phytoremediation of heavy-metal polluted water bodies. A prerequisite for metal removal, however, is the tolerance of the organism to the pollutant, e.g., the metal zinc (Zn). Duckweeds have been shown to differ in their tolerances to Zn, however, despite them most commonly co-occurring with other species, there is a lack of research concerning the effect of species interactions on Zn tolerance. Here we tested whether the presence of a second species influenced the growth rate of the three duckweed species Lemna minor, Lemna gibba, and Lemna turionifera. We used four different Zn concentrations in a replicated microcosm experiment under sterile conditions, either growing the species in isolation or in a 2-species mixture. The response to Zn differed between species, but all three species showed a high tolerance to Zn, with low levels of Zn even increasing the growth rates. The growth rates of the individual species were influenced by the identity of the competing species, but this was independent of the Zn concentration. Our results suggest that species interactions should be considered in future research with duckweeds and that several duckweed species have high tolerance to metal pollution, making them candidates for phytoremediation efforts.

scholarly journals Estimation of above-ground phytomass and carbon in tree resources outside the forest (TROF): A geo-spatial approach

2015 ◽  
Vol 24 (1) ◽  
pp. 34-40 ◽  
Author(s):  
B. P. Heyojoo ◽  
S. Nandy
Keyword(s):  
Satellite Image ◽  
Uttar Pradesh ◽  
Individual Species ◽  
Individual Tree ◽  
Spatial Approach ◽  
Specific Standard ◽  
Vegetation Carbon ◽  
Carbon Project ◽  
The Individual ◽  
Species Specific

This study aims to estimate above-ground phytomass and carbon of TROF ecosystem in part of Bijnor district in Uttar Pradesh state of India using IRS P6 LISS-IV satellite image by geo-spatial approach coupled with field sampling. Chacko’s formula was referred to compute number of samples in each TROF types and the sample plot size in each stratum was adopted from Vegetation Carbon Project (VCP) under National Carbon Project (NCP). With the help of field data consisting mainly the height and girth information, volume of each individual tree per plot was obtained using site and tree species-specific standard volumetric equations. The phytomass was calculated by multiplying volume with Biomass Expansion Factor (BEF) then with regional specific gravity of the individual species and summed up in each plot to get total phytomass per plot. The total phytomass per plot was reported to be maximum 544.00 t/ha for linear TROF followed by 121.89 t/ha for block TROF. The carbon from phytomass was obtained by multiplying the total phytomass by a conversion factor that represents the average carbon content in phytomass. Spectral modeling for phytomass with different bands and indices were established and the best fit curve (R2 = 0.552) with red band was applied to generate phytomass and carbon distribution map of the study area.Banko Janakari, Vol. 24, No. 1, pp. 34-40

scholarly journals Random Mutagenesis of Filamentous Fungi Strains for High-Yield Production of Secondary Metabolites: The Role of Polyamines

2020 ◽  
Author(s):  
Alexander A. Zhgun
Keyword(s):  
Filamentous Fungi ◽  
Random Mutagenesis ◽  
Strain Improvement ◽  
Main Tool ◽  
High Yield ◽  
Individual Species ◽  
Airborne Spores ◽  
Yield Production ◽  
Improvement Programs ◽  
The Individual

A filamentous fungus (also called molds or moldy fungus) is a taxonomically diverse organism from phylum Zygomycota and Ascomycota with filamentous hyphae and has the ability to produce airborne spores or conidia. Currently, more than 70,000 molds are known, and some of them contain unique and unusual biochemical pathways. A number of products from such pathways, especially, the secondary metabolite (SM) pathways are used as important pharmaceuticals, including antibiotics, statins, and immunodepresants. Under different conditions, the individual species can produce more than 100 SM. The strain improvement programs lead to high yielding in target SM and significant reduction of spin-off products. The main tool for the strain improvement of filamentous fungi is random mutagenesis and screening. The majority of industrial overproducing SM strains were developed with the help of such technique over the past 50–70 years; the yield of the target SM increased by 100- to 1000-fold or more. Moreover, most of the strains have reached their technological limit of improvement. A new round of mutagenesis has not increased overproduction. Recently, it was shown that that the addition of exogenous polyamines may increase the production of such improved strains of filamentous fungi. The possible molecular mechanism of this phenomenon and its biotechnological applications are discussed.

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