Results of the WMT15 Metrics Shared Task

This paper presents the results of the WMT15 Metrics Shared Task. We asked participants of this task to score the outputs of the MT systems involved in the WMT15 Shared Translation Task. We collected scores of 46 metrics from 11 research groups. In addition to that, we computed scores of 7 standard metrics (BLEU, SentBLEU, NIST, WER, PER, TER and CDER) as baselines. The collected scores were evaluated in terms of system level correlation (how well each metric's scores correlate with WMT15 official manual ranking of systems) and in terms of segment level correlation (how often a metric agrees with humans in comparing two translations of a particular sentence)

Vegetation degradation promotes the invasion potential of Impatiens glandulifera in an oligotrophic mountain habitat

An annual plant Himalayan balsam (Impatiens glandulifera Royle) is globally widespread and one of the Europe’s well-investigated top invaders. Yet, there is very limited knowledge on the effects of environment on the invasion potential of this species. We focused on two questions: does this species indeed not invade the southern areas of the continent; and, does the environment affect some of its key invasibility traits. In an isolated model valley (Sharr mountain, Western Balkans), we jointly analyzed the soil (21 parameter), the life history traits of the invader (height, stem diameter, aboveground dw), and the resident vegetation (species composition and abundances, Ellenberg indicator values), and supplemented it by the local knowledge (semi-structured interviews). Uncontrolled discharge of fecal wastewaters directly into the local dense hydrological network fostered mass infestation of an atypical, nutrient poor habitat. The phenotypic plasticity of the measured invasion-related traits was very high in the surveyed early invasion (30-50% invader cover) stages. Different microhabitat conditions consistently correlated with its growth performance. The largest individuals were restricted to the deforested riparian habitats with extreme soil nutrient enrichment (primarily by P and K) and low-competitive, species-poor resident vegetation. We showed that ecological context can modify invasion-related traits, what could affect further invasion process. Finally, this species is likely underreported in the wider region; public attitude and loss of traditional ecological knowledge are further management risks

Phosphorus Deficiency Induced Silicon Mobilization in Grapevine Rhizosphere: A Field Study

Silicon (Si) uptake by crops is well studied and Si transporters have been characterized in various crop species, including grapevine. However, information on the rhizosphere mobilization of Si is still lacking and virtually no information is available on grapevine. Our previous study showed that grapevine is a phosphorus (P)-efficient species with a high root capacity to mobilize P from the rhizosphere by the released of organic anions (mainly citrate). The field experiment was established in 12-y-old vineyard with the cultivar ‘Chardonnay’, grafted on 5BB rootstock under extremely low P conditions (Olsen P < 3 mg kg-1). Four own-designed rhizotrons (80 cm depth) were installed in a vineyard enabling easy access to the new intact roots. The following treatments were performed: –P/–Si, +P/–Si, –P/+Si (soil application) and –P/+Si (foliar application). The samples of rhizosphere and bulk soils, root exudates from intact root tips and vine tissues (root and leaves) were collected at different growth stages according to Eichhorn-Lorentz (E-L) system: flowering (E-L stage 23), berries pea-size (E-L stage 31), and veraison (E-L stage 35). In addition to Si and P concentrations in the tissues, the expressions of VvALMT, VvMATE (encoding efflux transporters for malate and citrate, respectively), and VvNIP2.1 (encoding Si influx transporter) were also determined. Phosphate fertilization decreased, while low soil P and Si fertilization increased Si availability in the rhizosphere. At the flowering stage, –P plants accumulated more Si than the P-fertilized ones and was comparable to the Si-fertilized plants. Foliar application of Si was less effective in comparison with soil application unless at the veraison stage. The leaf Si concentrations showed a clear seasonal pattern being the highest at the veraison stage. Exudation rate of citrate also showed a clear seasonal pattern and was significantly higher in the –P/–Si than in +P/–Si plants, which was followed by an increased Si availability in the vine rhizosphere. Overall, low P conditions induced Si accumulation in the leaves due to increased exudation of organic anions that can also mobilize Si in the rhizosphere, thereby increasing Si uptake by grapevine

Silicon Differently Affects Apoplastic Binding of Excess Boron in Wheat and Sunflower Leaves

Monocots and dicots differ in their boron (B) requirement, but also in their capacity to accumulate silicon (Si). Although an ameliorative effect of Si on B toxicity has been reported in various crops, differences among monocots and dicots are not clear, in particular in light of their ability to retain B in the leaf apoplast. In hydroponic experiments under controlled conditions, we studied the role of Si in the compartmentation of B within the leaves of wheat (Triticum vulgare L.) as a model of a high-Si monocot and sunflower (Helianthus annuus L.) as a model of a low-Si dicot, with the focus on the leaf apoplast. The stable isotopes 10B and 11B were used to investigate the dynamics of cell wall B binding capacity. In both crops, the application of Si did not affect B concentration in the root, but significantly decreased the B concentration in the leaves. However, the application of Si differently influenced the binding capacity of the leaf apoplast for excess B in wheat and sunflower. In wheat, whose capacity to retain B in the leaf cell walls is lower than in sunflower, the continuous supply of Si is crucial for an enhancement of high B tolerance in the shoot. On the other hand, the supply of Si did not contribute significantly in the extension of the B binding sites in sunflower leaves. © 2023 by the authors

Duration of priming with silicon modulates antioxidative response of wheat to salinity stress

Priming with silicon (Si) may increase plant resistance to biotic and abiotic stresses, in particular in conjunction with its subsequent application. Yet, the very effect of the duration of priming with Si is less understood. Here, we investigated the effect of the duration of priming with Si on components of the antioxidative response of wheat exposed to a gradient of salinity stress. After priming with 1.5 mM Si(OH)4 (0, 1, and 3 days), wheat seedlings were exposed to different NaCl levels (0, 30, and 60 mM) without (-Si) or with (+Si) supply of 1.5 mM Si(OH)4. The activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), and the concentration of malondialdehyde (MDA) were measured in shoots and roots after 1 and 5 days of NaCl treatments. Interaction of priming duration and addition of Si on antioxidative variables were analyzed using general regression model. Overall, priming had no influence on -Si plants under salt stress. On the day 1 of NaCl exposure, priming duration did not affect SOD and APX activities neither in roots nor in shoots. However, on the day 5 of NaCl exposure longer priming with Si significantly increased the activities of APX and SOD in both roots and shoots. The activity of CAT showed no response to priming with Si and subsequent Si supply in both plant organs irrespectively of the duration of NaCl exposure. Interestingly, in both organs the concentrations of MDA as a proxy for oxidative damage of plant membranes were very clearly and consistently lower after 3 days of priming with Si (compared to 1 day or no priming) during the whole period of NaCl exposure. This study demonstrated that longer priming with Si can enhance the ameliorative effect of Si supply on the antioxidative response of wheat plants to a gradient of salinity stress