Compromiso con el trabajo y rendimiento en el trabajo: el papel moderador del apoyo organizacional percibido.

The present research was aim to examine whether the relationship between work engagement and objective task performance is moderated by perceived organizational support (POS). Based on the existing literature, perceived organizational support is hypothesized to strengthen the positive association between employees’ work engagement and their objective task performance. The hypotheses were tested on a sample of 1049 employees. Results of hierarchical regression analysis show that: (1) work engagement is positively related to objective task performance, and (2) the relationship between work engagement and objective task performance is moderated by POS, such that the positive relationship is more significant when POS higher than lower. In the end, theoretical and practical implications, and suggestions for future research are discussed.La presente investigación tuvo el objetivo de examinar si la relación entre compromiso con el trabajo y el rendimiento en los objetivos de las tareas está moderada por el apoyo perceptivo de la organización (APO). En base a la literatura existente, el apoyo percibido de la organización se hipotetiza que fortalece la asociación positiva entre el compromiso laboral de los empleados y su rendimiento en los objetivos de las tareas. Las hipótesis fueron comprobadas en una muestra de 1049 empleados. Los resultados del análisis de regresión jerárquico muestran que: (1) el compromiso en el trabajo está positivamente relacionado con el rendimiento en los objetivos de las tareas, y (2) la relación entre compromiso en el trabajo y el rendimiento en los objetivos de las tareas está moderado por el APO, de modo que la relación positiva es más significativa cuando el APO es mayor. Al final se discuten las implicaciones teóricas y prácticas, y las sugerencias para futuras investigaciones

Foliar P nutrition of European beech (Fagus sylvatica L.) depends on the season but remains unaffected by co-cultivation with silver fir (Abies alba Mill.)

Beech (Fagus sylvatica) and silver fir (Abies alba) are often cultivated in mixed stands and, hence, compete for water and nutrients. Besides nitrogen (N), also phosphorus (P) is an important nutrient for growth and development. Beech trees in Central Europe grow on both P-poor and P-rich soils, thereby showing similar growth and low variation in foliar P. The central aim of the present study was to test the hypothesis that variations in foliar P contents of beech are driven by seasonal changes rather than by the competition with silver fir. It was further hypothesized that P contents in silver fir needles depend on needle age and forest site. To test these hypotheses, P contents and P fractions, i.e. organic-bound P (P$_{org}$) and inorganic phosphate P (P$_{i}$), were measured in the foliage of beech trees from pure beech and mixed beech/silver fir plots as well as in needles of silver fir of the mixed plots. The forest sites investigated are located in Central Europe in the Black Forest, Germany, and in Croatia near the south-eastern distribution limit of beech and are all poor in plant-available soil P. The analyses showed that the main driver of P contents and P fractions in beech leaves at all forest sites is the season and that competition with silver fir had no effect. Hence, the present results demonstrate the high plasticity of beech trees to adapt to both poor plantavailable soil P and competition with silver fir. Total P contents of silver fir needles were higher at the Croatian site compared to the Black Forest sites and originated from higher foliar P$_{i}$ contents. One third of the P present in current-year needles in late summer was remobilized and exported until the needles reached the age of 1 year. The difference in P contents between current-year and 1-year-old needles can be seen as the amount of P resorbed from 1-year-old needles in summer during the generation of new needles to support the P demand of current-year needles for growth and development

Integrative multi‐omics analyses of date palm (Phoenix dactylifera) roots and leaves reveal how the halophyte land plant copes with sea water

Date palm (Phoenix dactylifera L.) is able to grow and complete its life cycle while being rooted in highly saline soils. Which of the many well-known salt-tolerance strategies are combined to fine-tune this remarkable resilience is unknown. The precise location, whether in the shoot or the root, where these strategies are employed remains uncertain, leaving us unaware of how the various known salt-tolerance mechanisms are integrated to fine-tune this remarkable resilience. To address this shortcoming, we exposed date palm to a salt stress dose equivalent to seawater for up to 4 weeks and applied integrative multi-omics analyses followed by targeted metabolomics, hormone, and ion analyses. Integration of proteomic into transcriptomic data allowed a view beyond simple correlation, revealing a remarkably high degree of convergence between gene expression and protein abundance. This sheds a clear light on the acclimatization mechanisms employed, which depend on reprogramming of protein biosynthesis. For growth in highly saline habitats, date palm effectively combines various salt-tolerance mechanisms found in both halophytes and glycophytes: “avoidance” by efficient sodium and chloride exclusion at the roots, and “acclimation” by osmotic adjustment, reactive oxygen species scavenging in leaves, and remodeling of the ribosome-associated proteome in salt-exposed root cells. Combined efficiently as in P. dactylifera L., these sets of mechanisms seem to explain the palm's excellent salt stress tolerance

<em>In vitro</em> proliferation of Saskatoon berry (<em>Amelanchier alnifolia</em> Nutt) is affected by plant growth regulators and their concentrations but less by carbon source

648-654There is a high demand for Saskatoon berry (Amelanchier alnifolia Nutt) seedlings but a limited supply. To optimize the micropropagation system, and to evaluate the feasibility of replacing sucrose by table sugar, the effects of commonly used plant growth regulators (PGRs) and carbon sources on its multiplication ratio (MR) and mean shoot length (LS) were examined. MR and LS were significantly affected by different types of auxins and cytokinins, as well as their concentrations except little impact of auxin concentrations on LS. Treatments containing indole acetic acid (IAA) and indole butyric acid (IBA) achieved higher MR and LS than that containing naphthalene acetic acid (NAA), and the highest MR was 5.7 with 1.6 cm of LS in the treatment containing 0.1 mg L-1 IBA. Except kinetin (KT), low content of thidiazuron (TDZ) accomplished a high MR of 4.8 but less shoots growth, 6-benzylaminopurine (BAP) and zeatin (ZT) clearly increased the multiplication and shoot growth. The highest MR of 5.2 with LS of 2.8 cm was achieved in the presence of 4.0 mg L-1 BAP. Table sugar was an ideal substitute for sucrose, therefore, the cost of mass-scale production could be drastically reduced without compromising on the quality and quantity of plantlets

Work engagement and job performance: the moderating role of perceived organizational support

La presente investigación tuvo el objetivo de examinar si la re- lación entre compromiso con el trabajo y el rendimiento en los objetivos de las tareas está moderada por el apoyo perceptivo de la organización (APO). En base a la literatura existente, el apoyo percibido de la organización se hipotetiza que fortalece la asociación positiva entre el compromiso laboral de los empleados y su rendimiento en los objetivos de las tareas. Las hipó- tesis fueron comprobadas en una muestra de 1049 empleados. Los resulta- dos del análisis de regresión jerárquico muestran que: (1) el compromiso en el trabajo está positivamente relacionado con el rendimiento en los objeti- vos de las tareas, y (2) la relación entre compromiso en el trabajo y el ren- dimiento en los objetivos de las tareas está moderado por el APO, de mo- do que la relación positiva es más significativa cuando el APO es mayor. Al final se discuten las implicaciones teóricas y prácticas, y las sugerencias para futuras investigaciones.The present research was aim to examine whether the relation- ship between work engagement and objective task performance is moder- ated by perceived organizational support (POS). Based on the existing lit- erature, perceived organizational support is hypothesized to strengthen the positive association between employees’ work engagement and their objec- tive task performance. The hypotheses were tested on a sample of 1049 employees. Results of hierarchical regression analysis show that: (1) work engagement is positively related to objective task performance, and (2) the relationship between work engagement and objective task performance is moderated by POS, such that the positive relationship is more significant when POS higher than lower. In the end, theoretical and practical implica- tions, and suggestions for future research are discussed

Effects of Extreme Drought and Heat Events on Leaf Metabolome of Black Alder (<i>Alnus glutinosa</i> L.) Growing at Neighboring Sites with Different Water Availability

Riparian tree species are thought to be sensitive to the more frequent and intensive drought and heat events that are projected to occur in the future. However, compared to waterlogging, information about the responses of these tree species to water limitation and heat is still scare. Black alder (Alnus glutinosa L.) is a riparian tree species with significant ecological and economic importance in Europe. In the present study, we investigated the physiological responses of black alder (Alnus glutinosa L.) to different water availabilities growing at neighboring sites. Compared to trees with unlimited water source, trees with a limited water source had 20% lower leaf hydration, 39% less H2O2 contents, and 34% lower dehydroascorbate reductase activities. Concurrent with dramatically accumulated glutathione and phenolic compounds, leaf glutathione contents were two times higher in trees with limited water than in trees with sufficient water. Limited water availability also resulted in increased abundances of sugars, sugar acids, and polyols. Serine, alanine, as well as soluble protein related to nitrogen metabolism were also accumulated under limited water conditions. In contrast to sulfate, leaf phosphate contents were significantly increased under limited water. No significant effects of water conditions on malondialdehyde and ascorbate contents and fatty acid abundances were observed. The present study improves our understanding of the physiological responses of black alder to different water conditions. Our findings highlight this riparian species is at least to some extent resistant to future drought with a well-regulated system including antioxidative and metabolic processes and its potential as an admixture candidate for afforestation in either water-logged or dry areas, particularly in nitrogen limited habitats

Work engagement and job performance: the moderating role of perceived organizational support

La presente investigación tuvo el objetivo de examinar si la re- lación entre compromiso con el trabajo y el rendimiento en los objetivos de las tareas está moderada por el apoyo perceptivo de la organización (APO). En base a la literatura existente, el apoyo percibido de la organización se hipotetiza que fortalece la asociación positiva entre el compromiso laboral de los empleados y su rendimiento en los objetivos de las tareas. Las hipó- tesis fueron comprobadas en una muestra de 1049 empleados. Los resulta- dos del análisis de regresión jerárquico muestran que: (1) el compromiso en el trabajo está positivamente relacionado con el rendimiento en los objeti- vos de las tareas, y (2) la relación entre compromiso en el trabajo y el ren- dimiento en los objetivos de las tareas está moderado por el APO, de mo- do que la relación positiva es más significativa cuando el APO es mayor. Al final se discuten las implicaciones teóricas y prácticas, y las sugerencias para futuras investigaciones.The present research was aim to examine whether the relation- ship between work engagement and objective task performance is moder- ated by perceived organizational support (POS). Based on the existing lit- erature, perceived organizational support is hypothesized to strengthen the positive association between employees’ work engagement and their objec- tive task performance. The hypotheses were tested on a sample of 1049 employees. Results of hierarchical regression analysis show that: (1) work engagement is positively related to objective task performance, and (2) the relationship between work engagement and objective task performance is moderated by POS, such that the positive relationship is more significant when POS higher than lower. In the end, theoretical and practical implica- tions, and suggestions for future research are discussed