TMT-Based Proteomic Profiling Reveals the Molecular Mechanism in the Cold Tolerance of Rhododendron Aureum Georgi.

Background: Cold stress is one of the important factors that restrict plant growth and regional distribution. Under cold acclimation conditions, plants growing in temperate zones reprogram the gene expression in the cells, making the plants better cope with the coming cold stress. However, under natural environmental conditions, the climate is complex and changeable. The sudden large temperature drop will bring serious disasters to plants. Rhododendron aureum Georgi, as an evergreen plant growing in high altitude areas of Changbai Mountain, the harsh ecological environment may endow it with different cold tolerance characteristics. Results: In this study, the proteomic difference between samples under control and cold stress were compared pairwise. A total of 360 DAPs were identified, of which 175 were down-regulated and 185 were up-regulated when comparing these two sets of data. The high cold tolerance of Rhododendron plants can be attributed to: accumulation of chaperone proteins; the up-regulation of components related to translation; enhancement of catabolism and reduction in anabolism, provide energy for plants and fight against cold stress; enhanced cellular antioxidant capacity; modification of components in cell wall, membrane, and cytoskeleton. Conclusion: These results provide an in-depth understanding of the cold tolerance mechanism of Rhododendron. The identified genes and metabolic pathways provide a certain reference for the genetic improvement of plant cold tolerance.

Vegetation Heterogeneity Effects on Soil Macro-Arthropods in an Alpine Tundra of the Changbai Mountains, China

The harsh environmental conditions in alpine tundra exert a significant influence on soil macro-arthropod communities, yet few studies have been performed regarding the effects of vegetation heterogeneity on these communities. In order to better understand this question, a total of 96 soil macro-arthropod samples were collected from four habitats in the Changbai Mountains in China, namely, the Vaccinium uliginosum habitat, Sanguisorba sitchensis habitat, Rhododendron aureum habitat, and Deyeuxia angustifolia habitat. The results revealed that the taxonomic composition of the soil macro-arthropods varied among the habitats, and that dissimilarities existed in these communities. The abundance, richness and diversity in the D. angustifolia habitat were all at their maximum during the sampling period. The vegetation heterogeneity affected the different taxa of the soil macro-arthropods at various levels. In addition, the vegetation heterogeneity had direct effects not only on soil macro-arthropod communities, but also indirectly impacted the abundance, richness and diversity by altering the soil fertility and soil texture. Overall, our results provide experimental evidence that vegetation heterogeneity can promote the abundance, richness and diversity of soil macro-arthropods, yet the responses of soil macro-arthropods to vegetation heterogeneity differed among their taxa.