Acer Pseudoplatanus Seedlings Research Articles

Pasture Management to Reduce the Risk of Acer pseudoplatanus Poisoning While Preserving Ecological Sustainability

In spring, grazing equids may suffer from a severe rhabdomyolysis syndrome named atypical myopathy. This environmental intoxication results from ingestion of toxins contained in Acer pseudoplatanus seedlings. The aim of this study was to investigate the effectiveness of herbicide spraying and mowing to reduce the toxic pressure of sycamore seedlings. In a first experiment, the efficacy of three herbicides to eradicate seedlings was compared to mowing. In a second experiment, the influence of the mowing timing on pasture productivity was determined. In both experiments, sycamore seedling counting, grass height and botanical composition were determined. In experiment 2, the final harvest biomass and its nutritional value were also determined. Herbicides and mowing both reduced the number of seedlings, which nevertheless disappear naturally over time without intervention (i.e., in control areas). As opposed to mowing, herbicide spraying altered the composition of the pasture flora. Both sprayed and mowed seedlings remain toxic until full decomposition. Early mowing (i.e., early April) did not affect the harvest yield. Late mowing (i.e., end of April) reduced the harvest yield but its nutritional value fitted the horses’ need. In conclusion, mowing is the best strategy to reduce the risk of Acer pseudoplatanus poisoning in grazing equids while preserving ecological sustainability and nutritional value of pastures.

Kuraklık Stresi Altındaki İki Akçaağaç Türünün (Acer negundo ve Acer pseudoplatanus) Fidanlarının Gaz Değişim Parametrelerinin Karşılaştırılması

In this study, two-year-old bare-root Acer negundo and Acer pseudoplatanus seedlings were grown indoors (control vs. drought-stressed) and outside the hoop house to examine leaf gas exchange parameters in the late growing period. Besides morphological features, several gas exchange parameters, such as net photosynthetic rate (Anet), transpiration rate (E), stomatal conductance (gs), intercellular CO2 to ambient CO2 (Ci/Ca), water use efficiency (WUE=Anet/E), intrinsic water use efficiency (iWUE=Anet/gs) were measured. As a result, A. pseudoplatanus seedlings had a higher stem height growth. A. negundo had a higher Anet, and a lower iWUE and Ci/Ca than A. pseudoplatanus. Seedlings grown under control treatment had a higher Anet, gs, E, and a lower iWUE, WUE, and Ci/Ca values than other treatments. In conclusion, there was no significant difference between the two Acer species in terms of gas exchange parameters. However, it can be said that A. negundo and A. pseudoplatanus are drought resistant.

Hydraulic-stomatal coordination in tree seedlings: tight correlation across environments and ontogeny in Acer pseudoplatanus.

Hydraulic conductance is recognized as a major determinant of gas exchange and productivity. However, whether this also applies to seedlings, a critically important stage for vegetation regeneration, has been largely unknown. We analyzed the hydraulic and stomatal conductance of leaves and shoots for 6-wk-old Acer pseudoplatanus seedlings emerging in different lowland and treeline habitats and under glasshouse conditions, respectively, as well as on 9-, 15- and 18-wk-old plants, and related findings to leaf and xylem anatomical traits. Treeline seedlings had higher leaf area-specific shoot hydraulic conductance (Kshoot-L ), and stomatal conductance (gs ), associated with wider xylem conduits, lower leaf area and higher stomatal density than lowland and glasshouse-grown plants. Across the first 18 wk of development, seedlings increased four-fold in absolute shoot hydraulic conductance (Kshoot ) and declined by half in Kshoot-L , with correlated shifts in xylem and leaf anatomy. Distal leaves had higher leaf hydraulic conductance (Kleaf ) and gs compared to basal leaves. Seedlings show strong variation across growth environments and ontogenetic shifts in hydraulic and anatomical parameters. Across growth sites, ontogenetic stages and leaf orders, gs was tightly correlated with Kshoot-L and Kleaf , balancing hydraulic supply with demand for the earliest stages of seedling establishment.

Carbon dynamics of Acer pseudoplatanus seedlings under drought and complete darkness.

Carbon (C) storage is considered a key component to plant survival under drought and shade, although the combined effects of these factors on survival remain poorly understood. We investigated how drought and shade alter the C dynamics and survival of tree seedlings, and whether drought limits the access to or usage of stored C. We experimentally applied two levels of soil humidity (well-watered versus drought, the latter induced by dry-down) and light availability (light versus complete darkness) on 1-year-old seedlings of Acer pseudoplatanus L. for 3 months. We quantified the survival, biomass, growth rate and non-structural carbohydrates (NSC) of seedlings at their time of death or at the end of the experiment for those that survived. We found that the soil dried out faster when drought was combined with light than when it was combined with complete darkness. Seedlings subjected to both drought and light showed reduced growth and reached 100% mortality earlier than any other treatment, with the highest NSC concentrations at the time of death. Seedlings exposed to both drought and complete darkness died significantly earlier than seedlings exposed to complete darkness only, but had similar NSC concentrations at time of their death, suggesting that drought accelerated the use of stored C under complete darkness. Complete darkness significantly reduced seedling growth and whole-plant NSC concentrations regardless of soil humidity, while root NSC concentrations were significantly more reduced when complete darkness was combined with drought conditions. Thus, the C dynamics in A. pseudoplatanus seedlings under complete darkness was not hindered by drought, i.e., the access and use of stored C was not limited by drought. The contrasting growth and C storage responses driven by drought under light versus complete darkness are consistent with a key role of the drought progression in the C dynamics of trees.

Mitochondrial function is altered in horse atypical myopathy

Equine atypical myopathy in Europe is a fatal rhabdomyolysis syndrome that results from the ingestion of hypoglycin A contained in seeds and seedlings of Acer pseudoplatanus (sycamore maple). Acylcarnitine concentrations in serum and muscle OXPHOS capacity were determined in 15 atypical myopathy cases. All but one acylcarnitine were out of reference range and mitochondrial respiratory capacity was severely decreased up to 49% as compared to 10 healthy controls. The hallmark of atypical myopathy thus consists of a severe alteration in the energy metabolism including a severe impairment in muscle mitochondrial respiration that could contribute to its high death rate.

Competition for nitrogen between Fagus sylvatica and Acer pseudoplatanus seedlings depends on soil nitrogen availability.

Competition for nitrogen (N), particularly in resource-limited habitats, might be avoided by different N acquisition strategies of plants. In our study, we investigated whether slow-growing European beech and fast-growing sycamore maple seedlings avoid competition for growth-limiting N by different N uptake patterns and the potential alteration by soil N availability in a microcosm experiment. We quantified growth and biomass indices, 15N uptake capacity and N pools in the fine roots. Overall, growth indices, N acquisition and N pools in the fine roots were influenced by species-specific competition depending on soil N availability. With inter-specific competition, growth of sycamore maple reduced regardless of soil N supply, whereas beech only showed reduced growth when N was limited. Both species responded to inter-specific competition by alteration of N pools in the fine roots; however, sycamore maple showed a stronger response compared to beech for almost all N pools in roots, except for structural N at low soil N availability. Beech generally preferred organic N acquisition while sycamore maple took up more inorganic N. Furthermore, with inter-specific competition, beech had an enhanced organic N uptake capacity, while in sycamore maple inorganic N uptake capacity was impaired by the presence of beech. Although sycamore maple could tolerate the suboptimal conditions at the cost of reduced growth, our study indicates its reduced competitive ability for N compared to beech.

Advance Fagus sylvatica and Acer pseudoplatanus seedlings dominate tree regeneration in a mixed broadleaved former coppice-with-standards forest

This study assessed the species composition and the development of regeneration plots in gaps created by a windstorm in a mixed-species broadleaved stand. The stand was a former coppice-with-standards characterized by a high broadleaved tree species diversity. Thirteen years after gap creation, all gaps were fully stocked and the regeneration was almost exclusively dominated by Fagus sylvatica and Acer pseudoplatanus seedlings, two species characterized by a high shade tolerance in their early stages. All other species (Quercus sp., Fraxinus excelsior, Carpinus betulus, Acer campestre, Acer platanoïdes, Sorbus torminalis, Tilia sp.) were either absent from the regeneration or completely over-topped by the two dominant species. These features were ascribed to a regime of periodic natural or anthropic disturbance of intermediate intensity, where small gaps are regularly created in the canopy. This regime results in a succession of short, open and closed canopy episodes that eventually promote shade-tolerant species. During this regime, the shade-tolerant species are able to build a strong advance regeneration that is ready to outgrow the other species when gaps are created. If the management objective is to maintain species diversity during the regeneration process, the development of this advance regeneration will have to be strictly controlled.

Nitrogen and base cation uptake in seedlings of Acer pseudoplatanus and Calamagrostis villosa exposed to an acidified environment

The effects of solution acidity and form of nitrogen on net nutrient uptake rates in Acer pseudoplatanus and Calamagrostis villosa seedlings were examined as part of a complex ecological study. Uptake rates were measured by the depletion method under controlled conditions (temperature 20 °C, irradiance 400 µmol m−2 s−1 PAR) from a nutrient solution containing 1.5 mM nitrogen in the form of nitrate or ammonium or an equimolar mixture of both. The solution acidity was kept constant at pH 5.5 (control treatment), 4.5 or 3.5 (low pH treatments). Strongly acid pH decreased or stopped the uptake rates of NO3−, Mg2+ and Ca2+, but the uptake of NH4 + was not changed in both species Ammonium ions reduced the uptake rate of NO3 − in Acer but increased the uptake rate in Calamagrostis Ammonium as the sole source of nitrogen had a strong negative impact on the uptake rates of calcium and magnesium and this effect was independent of the media acidification usually connected with NH4 + uptake and assimilation. However, the negative effect of ammonium ions on the base cation uptake was more pronounced at low pH values.

Survival of Acer pseudoplatanus L. (sycamore) seedlings on metalliferous soils.

Seeds and seedlings of Acer pseudoplatanus L. (sycamore) were collected at sites contaminated by metals, originating either from mining spoil or from aerial deposition from metal processing industry, and at a number of relatively uncontaminated sites. Seedling growth was examined in relation to site of origin, both in nutrient solutions with elevated metal concentrations and in reciprocal transplant experiments in soils from the sites. Metal tolerance was not detected and there was no significant difference between plants from the different sites of origin. It was found, however, that roots could proliferate in uncontaminated zones of the soil and that, even in contaminated soils, most seedlings used in growth tests survived for at least three years despite impaired growth. Seedlings growing at the contaminated sites showed phytotoxic symptoms associated with high metal levels, but apparently healthy seedlings and saplings of different ages were also found. Some form of low level innate tolerance may be involved but it is suggested that phenotypic plasticity is more important than previously thought, potentially allowing survival until favourable conditions are encountered either temporally or spatially.

Responses of endomycorrhizal and non‐mycorrhizal plants of Acer pseudoplatanus to different levels of soluble and non‐soluble phosphorus

AbstractA greenhouse experiment compared growth and mineral nutrition of mycorrhizal and non‐mycorrhizal seedlings of Acer pseudoplatanus on a fumigated soil. The effects of mycorrhizal inoculation were examined at six rales of soluble phosphate and five rates of non‐soluble phosphate. Inoculation with Glomus mosseae markedly stimulated phosphorus uptake and growth only at the lowest level of soluble phosphorus. With 200 ppm of added monocalcium phosphate mycorrhizal infection depressed growth and considerably modified the relationships between yield and phosphorus concentration in plant tissues. The possible causes of growth depression at high level of added soluble phosphorus are discussed.

Influence de la mycorhization et de la fertilisation sur le comportement de jeunes plants d'érable sycomore (Acer pseudoplatanus Link.)

Abstract Influence of mycorrhizae and fertilization on Acer pseudoplatanus seedlings. A greenhouse experi‐ment compared growth and mineral nutrition of Acer pseudoplatanus seedlings on two soils with different fertilizations and with different endomycorrhization treatments. A strain of Glomus mosseae and a mycorrhizal complex from an A. pseudoplatanus stand prove to be much more growth efficient than the natural inoculum of the soils, mainly by improving phosphorus nutrition. These effects are additive to those of fertilization. This last result suggests that controlled mycorrhization can be of great practical interest even on rich soils.

Effects of light and photoperiodic conditions on abscisic acid in leaves and roots of Acer pseudoplatanus L.

Roots of Acer pseudoplatanus seedlings grown in liquid nutrient medium contained much lower levels of both free and bound abscisic acid than did leaves. The levels of free abscisic acid were similar in young expanding and of mature leaves, but lower in older senscing leaves. Growing plants under long days or short days did not influence the levels of free and bound abscisic acid in leaves. However, under both long days and short days, levels of bound abscisic acid were lower at the end of the dark period than 8 h later during the light period. Phaseic acid was also detected during the light period but never at the end of the dark period.

The Architecture of the Stem Apex and the Origin and Development of the Axillary Buds in Seedlings of Acer pseudoplatanus L.

The structure and changes in the size of the stem apex of seedling sycamores are described. There is no evidence for any regular increase in size of the apex from pastochrons 6 to 14 inclusive. The formation of the collar by the bases of each pair of foliar primordia and its association with the formation of axillary buds has been studied. The first pair of primordia on the axillary bud apex is always at right angles to the axil; the pair of primordia formed in the plane of the axil are always unequal. On extension growth these axillary buds give rise to lateral shoots which are anisophyllous. An explanation for the anisophylly is offered in terms of the spatial conditions obtaining in the developing axillary bud. The vascularization of the apex is briefly described.