Soil microbial trait-based strategies drive metabolic efficiency along an altitude gradient

Trait-based approaches provide a candidate framework for linking soil microbial community to ecosystem processes, yet how the trade-offs in different microbial traits regulate the community-level metabolic efficiency remains unknown. Herein we assessed the roles of the microbial taxa with particular trait strategies in mediating soil microbial metabolic efficiency along an altitude gradient on the Tibetan Plateau. Results showed that soil microbial metabolic efficiency declined with increasing altitude, as indicated by the increasing metabolic quotient (microbial respiration per unit biomass, qCO2) and decreasing carbon use efficiency (CUE). Both qCO2 and CUE were predominantly predicted by microbial physiological and taxonomic attributes after considering key environmental factors including soil pH, substrate quantity and quality. Specifically, the reduced metabolic efficiency was associated with higher investment into nutrient (particularly for phosphorus) acquisitions via enzymes. Furthermore, we identified key microbial assemblies selected by harsh environments (low substrate quality and temperature) as important predictors of metabolic efficiency. These results suggest that particular microbial assemblies adapted to nutrient limited and cold habitats, but at the expense of lower metabolic efficient at higher altitude. Our findings provide a candidate mechanism underlying community-level metabolic efficiency, which has important implications for microbial-mediated processes such as carbon dynamics under global climate changes.

New lineages of photobionts in Bolivian lichens expand our knowledge on habitat preferences and distribution of Asterochloris algae

We studied the biodiversity of Asterochloris photobionts found in Bolivian lichens to better understand their global spatial distribution and adaptation strategies in the context of a worldwide phylogeny of the genus. Based on nuclear ITS rDNA, the chloroplast rbcL gene and the actin type I gene we reconstructed a phylogenetic tree that recovered nine new Asterochloris lineages, while 32 Bolivian photobiont samples were assigned to 12 previously recognized Asterochloris lineages. We also show that some previously discovered Asterochloris photobiont species and lineages may occur in a broader spectrum of climatic conditions, and mycobiont species and photobionts may show different preferences along an altitude gradient. To reveal general patterns of of mycobiont specificity towards the photobiont in Asterochloris, we tested the influence of climate, altitude, geographical distance and effects of symbiotic partner (mycobiont) at the species level of three genera of lichen forming fungi: Stereocaulon, Cladonia and Lepraria. Further, we compared the specificity of mycobionts towards Asterochloris photobionts in cosmopolitan, Neotropical, and Pantropical lichen forming fungi. Interestingly, cosmopolitan species showed the lowest specificity to their photobionts, but also the lowest haplotype diversity. Neotropical and Paleotropical mycobionts, however, were more specific.

Cambial Activity and Phenology in Three Understory Species along an Altitude Gradient in Mexico

The aims of this study were to evaluate the cambial activity and phenology of three species with different life forms (Alchemilla procumbens, Acaena elongata and Ribes ciliatum) along an altitudinal gradient and to establish which environmental variables (light, soil humidity and temperature) had the greatest influence on cambial activity and phenological stages. Over two years, data on phenology, growth and cambium were gathered every four weeks in three to six sites per species in Sierra Nevada, Mexico. The results showed that Ribes is the only species that terminates cambial activity with leaves senescence and is influenced by the minimum soil temperature. The light environment influenced the vegetative stages in Alchemilla (cryptophyte), while in Acaena (hemicryptophyte), the mean soil temperature explained the findings related to leaf area during the dry season and growth along the gradient. In the three species, the reproductive phase dominated for a longer period at higher elevations, especially in Alchemilla. Only Ribes, the phanerophyte, showed a similar cambial activity to other trees and shrubs. Although cambium reactivates during the dry season, no xylogenesis occurs. The three species varied during the time in which vascular cambium was active, and this was dependent on the altitude. Specifically, the variation was more rhythmic in Ribes and switched on and off in Alchemilla. It is likely that, depending on the life form, vascular cambium may be more or less susceptible to one or more climate factors.

Determination of the total content of some secondary metabolites in various organs of the Dagestan samples of Capparis herbacea Willd.

Relevance, material and methods. Purpose of the work: comparative assessment of the content of the sum of phenolic compounds exhibiting antioxidant activity in various organs of herbaceous capers C. herbacea Willd. The 4 samples of C. herbaceawere collected from natural populations of Dagestan during the flowering and fruiting phases in the summer of 2019. The collected raw materials were divided into fractions (organs), dried in the shade to an air-dry mass, then subjected to further analysis to determine the total content of flavonoids, anthocyanins by the spertrophotometric method on SF-56; the total content of antioxidants by the amperometric method on the instrument of express analysis "Color-Yauza-001-AAA ".Results. During the analysis, good indicators were obtained for the content of the studied compounds. Thus, in terms of the content of flavonoids, the greatest variation is seen in the stems of herbaceous capers (0.34-0.86%) compared to their content in leaves and inflorescences (2.67-2.97% and 2.45-2.90%, respectively). The amount of anthocyanins varies in all organs within the range of 0.05-0.23%. The smallest spread is observed in the total content of antioxidants in the fruits of herbaceous capers (21.35-21.40 mg/l), while in inflorescences this indicator varies greatly (27.44-42.19 mg/l). It is noteworthy that the samples with a high value of antioxidants showed a low content of flavonoids, thereby indicating that flavonoids are not the main components in the antioxidant system of the studied caper species. An important condition determining the variability of the content of phenolic compounds in various plant organs is a complex of abiotic environmental factors. The study of this factor (altitude gradient) revealed a significant relationship with the accumulation of flavonoids in all organs, which has a multi-vector nature (correlation coefficient r*= 0.57; 0.56; -0.47), respectively, in stems, leaves, and inflorescences (P<0,05). A positive relationship in the accumulation of anthocyanins is observed with the height in caper leaves. In all other cases, the connection is random. In addition, the analysis of variance revealed that a large difference in the variability of the studied compounds is observed between individual groups of plants in the absence of intragroup variability.

Community Richness, Height, Coverage, and Spatial Distribution Mediate Grasshopper Abundance in the Upper Reaches of Heihe River, China

Species interactions are often context-dependent and complex, such as the grasshopper community and phytoecommunity. The adaption of grasshopper abundance and plant community were determined by topographical heterogeneity. However, it remains vague about how vegetation community, such as coverage, abundance and height, influence the spatial distribution pattern of grasshopper abundance at the altitude gradient. The geostatistical methods were used in natural grassland of the upper reaches of Heihe River to quantify the relationship of spatial correlation. A 5-years investigation shown that 3149 of grasshoppers was collected，belonging to 3 families, 10 genera, and 13 species. The semivariable function of grasshopper abundance and vegetation community followed a nonlinear model. Meanwhile, horizontal distribution of two communities was a clear flaky and plaque distribution pattern, especially at the altitude gradient. The abundance of grasshoppers is opposite to the height and coverage of vegetation and the overall follow ability of coverage, while the local following is consistent. Such as grasshopper abundance, the above 2750m sample with the opposite trend, the following areas were consistent. The grasshoppers exhibited the varieties on vegetation characters among all directions. On the different habits, the spatial distribution formed uniform trends; meanwhile, on the same, the trends diversified with altitude gradient, formed embedded striped patches structure.