Aims
The aim of the study was to investigate N biogeochemistry of four neighboring, high mountain plant communities and to identify main factors which drive variability among them. We hypothesized ...that the vegetation types differ in terms of N transformations, and that spatial differentiation of the communities and dominant growth form can reflect an existence of several N-environments along an elevational gradient.
Methods
Plant and soil N characteristics were studied in four vegetation types: heathland, scrub, sward and tall forb. Leaf nitrate reductase activity and total N were measured in the dominant species. Soil pH, total C, N, inorganic and dissolved organic N concentrations were measured. The soil net N mineralization rate was examined.
Results
The DistLM and PERMANOVA analyses revealed that variability among the vegetation types was driven primarily by elevation, soil N–NH
4
+
, soil pH and soil total C. We identified three distinct N-environments along an elevational gradient. The “N-poor alpine” located at the highest altitudes, strongly N-limited and dominated by dwarf-shrub. The "N-mixed subalpine" located in the middle of the gradient and covered by scrub and sward. It was characterized by moderate N turnover rate. The "N-rich subalpine" occurred at lowest locations and was covered by subalpine tall forb community. It exhibited the highest dynamics of N transformations and was rich in inorganic N.
Conclusion
Three main N-environments were identified: N-poor alpine, N-mixed subalpine, N-rich subalpine. Variability among the vegetation types was driven primarily by elevation, soil N–NH
4
+
, soil pH and soil total C.
This investigation was conducted to identify the content of metals in
Calluna vulgaris
(family
Ericaceae
),
Empetrum nigrum
(family
Ericaceae
),
Festuca vivipara
(family
Poaceae
) and
Thymus praecox
...subsp.
arcticus
(family
Lamiaceae
), as well as in the soils where they were growing in eight geothermal heathlands in Iceland. Investigation into the vegetation of geothermal areas is crucial and may contribute to their proper protection in the future and bring more understanding under what conditions the plants respond to an ecologically more extreme situation. Plants from geothermally active sites were enriched with metals as compared to the same species from non-geothermal control sites (at an average from about 150 m from geothermal activity). The enriched metals consisted of Cd, Co, Cu, Fe and Ni in
C. vulgaris
; Cd, Mn and Ti in
E. nigrum
; Hg and Pb in
F. vivipara
; and Cd, Fe and Hg in
T. praecox
. Notably,
C. vulgaris
,
E. nigrum
,
F. vivipara
and
T. praecox
had remarkably high concentrations of Ti at levels typical of toxicity thresholds. Cd and Pb (except for
C. vulgaris
and
F. vivipara
) were not accumulated in the shoots of geothermal plants.
C. vulgaris
from geothermal and control sites was characterised by the highest bioaccumulation factor (BF) of Ti and Mn;
E. nigrum
and
F. vivipara
by the highest BF of Ti and Cr; and
T. praecox
by the highest BF of Ti and Zn compared to the other elements. In comparison with the other examined species,
F. vivipara
from geothermal sites had the highest concentration of Ti in above-ground parts at any concentration of plant-available Ti in soil.
Full-size members of the ABCG (ATP-binding cassette, subfamily G) subfamily of ABC transporters have been found only in plants and fungi. The plant genes encoding full-size ABCGs identified so far ...appeared to be differentially regulated under various environmental constraints, plant growth regulators, and microbial elicitors, indicating a broad functional role of these proteins in plant responses to abiotic and biotic stress. Nevertheless, the structure and physiological function of full-size ABCGs in many plant species are still unknown. We have recently identified 16 genes encoding full-size ABCG proteins in cucumber and found that the transcripts of two of them,
CsABCG36
(
CsPDR8
) and
CsABCG40
(
CsPDR12
), are most abundant in roots and are significantly affected by phytohormones and auxin herbicide. In this study, we analyzed the structure and phylogeny of all the full-size cucumber ABCG transporters and studied the organ expression profiles of the remaining 14
CsABCG
genes. In addition, we investigated the effect of different plant growth regulators and the diterpene sclareolide on
CsABCG
expression in cucumber roots. Until now, the full-size plant ABCG transporters have been grouped into five different clusters. The new phylogenetic analysis of full-size ABCGs from model plants and cucumber clustered these proteins into six different subgroups. Interestingly, the expression profiles of cucumber
ABCG
genes assigned to the same clusters were not correlated, suggesting functional diversification or different regulatory mechanisms of the full-size cucumber ABCG proteins.
The anthropogenic impact of metals on aquatic environments is a risk for biota, and thus their levels must be controlled.
Callitriche cophocarpa
Sendtn. belongs to a genus with a potential for ...accumulation of elevated metal levels. Thus, it may provide consolidated evidence of contamination. Therefore, the aim of this investigation was to determine Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn in this species collected together with water and bottom sediments from rivers with various levels of pollution. Of these rivers, one less polluted and one more polluted was selected for the collection of
C. cophocarpa
for an experiment to compare its Cu and Zn concentration potential. Both metals were supplemented at concentrations 0.01, 0.02, 0.03, 0.05, 0.08 and 0.14 mg L
−1
of Cu as CuSO4 × 5H2O and 0.4, 0.6, 0,9, 1,35, 2.03 and 3.04 mg L
−1
of Zn as ZnSO
4
× 7H
2
O, and in the binary design containing (mg·L
−1
) 0.01Cu + 0.4Zn, 0.02Cu + 0.6Zn, 0.03Cu + 0.9Zn, 0.05Cu + 1.4Zn, 0.08Cu + 2.03 Zn and 0.14Cu + 3.04Zn. The upper concentrations of Cr, Cu, Mn and Zn in
C. cophocarpa
shoots from both types of rivers as well as of Ni and Pb in shoots from more polluted rivers were higher than the values typical for toxicity thresholds with no visible harmful effects, which may indicate accumulation abilities of
C. cophocarpa
for these metals. Both roots and shoots of
C. cophocarpa
may be included in the group of macroconcentrators for bottom sediments with respect to Cd, Co, Cr, Cu, Fe, Mn, Ni and Zn and deconcentrators of Pb. Greater accumulation of most metals in roots than in shoots indicates their restricted mobility and translocation by
C. cophocarpa
to shoots.
C. cophocarpa
from the less polluted river and exposed to all experimental solutions contained significantly higher levels of Cu and Zn than that from the more polluted river exposed to identical experimental solutions. The plants collected from the more polluted river influenced by surplus of metals and living under chemical stress could probably limit further accumulation by developing a resistance mechanism. Cu and Zn contents in
C. cophocarpa
were higher when treated with separate metals than for binary treatment both in the more and less polluted river. Such research presenting the impact of a combination of metals could be important for understanding and explaining the interactions of these elements which may influence their bioavailability in nature as well as importance in the evaluation of the risk of environmental toxicity.
In environmental research (i.e., plant ecophysiology, environmental microbiology, and environmental chemistry), some assays require incubation of samples at controlled temperature and darkness. Until ...now, due to a lack of equipment providing such possibility in situ, researchers had to move collected samples to the laboratory for incubation. Obviously, a delayed incubation and the ex situ conditions could seriously affect the assays’ results. A good example of analysis where water bath use is needed is the nitrate reductase activity (NRA) in vivo assay where plant tissue samples are incubated in buffer solution at a predetermined temperature. We designed a transportable water bath with a temperature control which enables in situ measurements in many types of environmental studies. The presented device is small in size featuring a thermally insulated chamber and an electronically controlled thermostat system powered by a 12-V battery. Due to its modular design, it can be transported comfortably in difficult terrain. The incubation process can be carried out continuously in stable temperature and darkness. In order to examine the field usability of the presented device, we conducted measurements of plant nitrate reductase activity in difficult field conditions. The in situ assays were carried out at high altitudes in the Karkonosze mountains, SW Poland. The NRA was studied in two alpine species (
Deschampsia caespitosa
and
Homogyne alpina
). Our results showed low NR activity in
H. alpina
(mean 0.31 μM NO
2
g
−1
DW h
−1
) and higher NRA in
D. caespitosa
(mean 2.7 μM NO
2
g
−1
DW h
−1
). The obtained results were highly reproducible and had small variability (low standard error values).
Calluna vulgaris
,
Carex rigida
,
Deschampsia flexuosa
,
Nardus stricta
and
Vaccinium myrtillus
are abundant in the vegetation of mountainous areas in Northern and Central Europe. Knowledge of their ...ability to accumulate increased amounts of metals could be useful in the evaluation of environmental pollution in the alpine tundra of high mountains. Additionally, this investigation may contribute to understanding the rate and direction of recent vegetation change in Karkonosze and similar types of environments. Our investigation revealed that
Carex rigida
,
C. vulgaris
and
V. myrtillus
contain excessive Mn concentrations in shoots with the highest BF for this element compared to the BFs of other elements.
C. rigida
, with Cu, Mn and Zn concentrations exceeding the toxicity thresholds for plants, seems to be the best metal phytoaccumulator for
Nardus stricta
grasslands
Carici
(
rigidae
)-
Nardetum
(CrN) and alpine heathlands
Carici
(
rigidae
)-
Festucetum airoidis
(CrFa) associations in the Karkonosze. Based on relevant BFs >1, it can be stated that the following plant available metals were transferred to shoots: Cu, Mn and Ni by
C. vulgaris
; Cd, Cu, Mn, Ni and Zn by
C. rigida
; Cd, Cu, Mn, Ni and Zn by
D. flexuosa
; Cu, Mn, Ni and Zn by
N. stricta
and Cu, Mn and Zn by
V. myrtillus
.
High phenotypic plasticity contributes to invasiveness of alien species. Goldenrods of American origin (Solidago canadensis, S. gigantea and Euthamia graminifolia) have successfully invaded Europe, ...and this success can be related to their high phenotypic plasticity. The aim of our study was to test the hypothesis of higher phenotypic plasticity of invasive goldenrods by comparing them with native taxa: closely related Solidago virgaurea and similar ecologically, invasive in other regions Tanacetum vulgare. The species studied were grown in a common garden on three different substrates with different fertilizers. After 3 years, the height and number of ramets, biomass production and allocation, phenology and nitrate reductase activity (NRA) were measured. The highest level of phenotypic plasticity was exhibited by the competitively weak native species S. virgaurea. The invasive species produced relatively high biomass and exhibited a moderate level of phenotypic plasticity. Variability in the studied traits did not always correlate with differences in substrates. The invasion success of non‐native goldenrods is not caused by their having a higher phenotypic plasticity than native species. Rather, the non‐natives should be considered as “Jack of all traits, and master of some”.
We tested the hypothesis of higher phenotypic plasticity in invasive goldenrods by comparing them with native taxa. The species studied were grown in a common garden on three different substrates with different fertilizers for 3 years. In conclusion, we can state that the invasion success of non‐native goldenrods is not caused by their having a higher phenotypic plasticity than native species. Rather, the non‐natives should be considered as “Jack of all traits, and master of some”.
The Karkonosze National Park, an unique mountainous biosphere reserve, is influenced by long-distance anthropogenic atmospheric transport of among others trace elements and additionally by local ...tourist centres, which may be supplementary sources of pollution. Discharged trace elements are non-degradable, and their level must be precisely monitored. Therefore, the concentrations of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Rb and Zn in Polytrichum commune and Polytrichastrum formosum collected from the Karkonosze sites influenced only by long-range pollution and from sites in the vicinity of local tourist centres were established. P. commune and P. formosum revealed the ability to accumulate higher concentrations of trace elements while growing in locally contaminated sites in comparison with sites free from such pollution. Therefore, both species may be utilised for bioindication in the Karkonosze National Park. Elevated levels of trace elements in both species (except for Hg) in comparison with concentrations typical for mosses from unpolluted sites point to the existence of pollution of this area. P. commune was a better bioindicator of Cd, Co, Cr, Cu, Mo, Ni, Pb and Rb than P. formosum, probably because of the larger gametophytes and its morphology, which appears prone to an increased uptake of trace elements from the atmosphere.
•P. commune and P. formosum may be used for bioindication in the Karkonosze.•Both species present higher trace element concentrations in the polluted sites.•P. commune is a better bioindicator than P. formosum.•Local tourist centres corresponded to a higher trace elements pollution.
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