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This study aims to gain insights into the allelopathic effects (by using leaf extracts) of the notorious invasive Solidago canadensis L. on seed germination of the associated Pterocypsela laciniata (Houtt.) C. Shih under different nitrogen (N) forms added: inorganic (NO3--N and NH4 -N), organic (urea-N), and mixed N (a mixture of the three N forms at 1:1:1 ratio). Among the two used concentrations of S. canadensis leaf extracts the higher exhibited inhibitory allelopathic effects on seedling height and biomass, germination potential, germination index, and vigor index of P. laciniata. N demonstrated positive effects on seed germination of P. laciniata. The effects of mixed and organic N on the seedling biomass of P. laciniata were more pronounced than those of inorganic N and control treatment. The vigor index of P. laciniata under mixed N was significantly higher than those under single N form and control treatment. Thus, organic and mixed N showed higher ecological effects on seed germination of P. laciniata than inorganic and single N form. All N forms could alleviate the inhibitory allelopathic effects of S. canadensis on seed germination of P. laciniata. Overall, the inhibitory allelopathic impact of S. canadensis on seed germination of native species may be attenuated under increased and diverse N deposition, thus it could prevent its further invasion.
Goldenrod (Solidago canadensis L.) is an invasive plant species in many countries except North America but a cut-flower species worldwide. There is a need to generate and propagate goldenrod clones efficiently for research and commercial purposes. A callus induction and plantlet regeneration system was developed by studying the influence of explant type and different concentrations of plant growth regulators. The highest callus production from leaf segments was obtained on Murashige and Skoog's medium (MS medium) supplemented with 1.0 mg/L naphthalene acetic acid (NAA) and 1.0 mg/L 6-benzylaminopurine (BA). Adventitious shoots could be regenerated directly from leaf explants without an intermediate callus phase with the highest shoot induction percentage of 87.2%. The largest number of adventitious shoots per leaf explant (3.2) was obtained on MS medium supplemented with 0.4 mg/L NAA and 2.0 mg/L BA. MS medium supplemented with 0.1 mg/L NAA and 1.0 mg/L BA was the best medium for axillary shoot regeneration from nodal segments. The highest root number and longest roots occurred on half-strength MS without the addition of any growth regulator. Rooted plantlets were then transferred to a soil-based growth medium, placed in a greenhouse, and acclimatized with 100% success. All surviving plants grew normally without showing any morphological variation when compared to those grow from seed. This regeneration protocol may be used to produce certain biotypes of goldenrod suitable for genetic transformation, rapid propagation of goldenrod for commercial purposes or for screening fungi and toxins as potential biocontrol agents against this weed.
Solidago canadensis, which is native to North America, is considered to be the most widespread invasive alien plant. The invasion of Solidago canadensis in China has resulted in serious environmental problems. Therefore, understanding the relationship between the geographical distribution of S. canadensis and bioclimatic variables, and then predicting the potential distribution of this species is essential for management actions and practices. Although several studies have delineated the potential distribution of S. canadensis in China, how this species would respond to variations in future climatic conditions remains unclear. In the present study, we predicted the potential distribution of S. canadensis under current and future climatic conditions using species distribution models. We also analyzed range shifting of this species under current and future climatic conditions. We arrived at several conclusions. First, the potential distribution of S. canadensis may expand 40% under future climatic condition compare with that of under current condition. Second, mean diurnal range, isothermality, mean temperature of the wettest quarter, mean temperature of the warmest quarter, precipitation of the driest month, and precipitation seasonality (coefficient of variation) are key bioclimatic variables in determine the potential distribution of S. canadensis. Third, expansion of S. canadensis can be partly attributed to the relatively warmer and wetter future bioclimatic condition than current one.
In Lower Silesia, three goldenrod species introduced from North America are found: Solidago gigantea Aiton (late goldenrod), S. canadensis L. (Canadian goldenrod) and S. graminifolia (L.) Elliott. (grass-leaved goldenrod). A native species is also found: Solidago virgaurea L. (common goldenrod). Distribution of these species was surveyed using sampling plots in a 10x10 km grid. The impact of increasing cover of goldenrods on biodiversity of patches of invaded vegetation was assessed. Biodiversity was described by the number of co-occurring vascular plant species inside 100 m2 plots placed in vegetation patches with goldenrods. The Shannon-Wiener diversity index was also calculated. The habitat preferences of particular Solidago species were examined. The most numerous goldenrod species in Lower Silesia were Solidago canadensis and S. gigantea, which were found in a similar number of plots. Distribution of thes two species were clumped in spatial scale of the whole study area. Solidago canadensis and S. gigantea do not differ with respect to their habitat preferences. The number of plant species as well as the Shannon-Wiener diversity index significantly decreased with increasing cover of S. canadensis and S. gigantea.
W pracy przedstawiono wyniki badań doświadczalnych nad oceną aktywności herbicydowej wyciągów wodnych z dwóch gatunków z rodzaju Solidago w stosunku do Thlaspi arvense i Stellaria media. W warunkach laboratoryjnych przygotowano wyciągi wodne z części podziemnych oraz nadziemnych Solidago gigantea i Solidago canadensis. Z wyciągów sporządzono roztwory robocze o stężeniu 10%. Jako rozpuszczalnika użyto wody destylowanej. Roztworami opryskano rośliny Thlaspi arvense i Stellaria media, a następnie oceniono ich wpływ na wytwarzanie świeżej masy. Roztwory uzyskane z wyciągów wodnych z Solidago gigantea i Solidago canadensis hamowały wytwarzanie świeżej masy przez Stellaria media i Thlaspi arvense. Reakcja tych gatunków była zróżnicowana. Większą wrażliwość na działanie badanych wyciągów wodnych obserwowano w przypadku Thlaspi arvense. Zaobserwowana w doświadczeniach aktywność herbicydowa badanych roztworów jest zbyt niska do zastosowań praktycznych..
Concentration of the metals Al, Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, Zn and V as well as N, P, K, Ca, Mg, Fe and S were measured in soils and in two tree species (leaves of Betula pendula and Salix caprea) and two herbs (whole above-ground parts of Solidago canadensis and Tanacetum vulgare) sampled from dumps in the Wałbrzych coal mine area (Lower Silesia, SW Poland). These plants, as used to evaluate the distribution of elements in the examined dumps, contained elevated levels of Cd, Co, Cu, Mn, Ni, Pb and Zn. Especially the highest levels of Mn in Betula pendula seriously exceed background values. Betula pendula characterized also the highest enrichment ratio for Mn, Salix caprea for Ni and Sr and Tanacetum vulgare for Cu. Test-t indicated that from both herbs Tanacetum vulgare accumulated much more K, N, S and Zn than Solidago canadensis and of both trees Salix caprea accumulated significantly more Cd, Cu, K and Ca than Betula pendula, while this last species accumulated significantly more Fe and Mn than Salix caprea. A post hoc LSD test indicated that all examined plants had similar enrichment ratios for Al, Pb and V.
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