Warming differentially affects above- and belowground ecosystem functioning of the semi-arid alpine grasslands.

Rapid climate warming is altering multiple ecosystem functions of alpine grasslands. However, the responses of the above- and belowground ecosystem multifunctionality (EMF) to climate warming might exhibit difference in semi-arid alpine grasslands. Based on manipulative field experiments at an alpine meadow and an alpine steppe, we explored warming effects on the functioning of alpine grassland ecosystems on the Tibetan Plateau. Warming significantly decreased plant diversity and aboveground biomass, but tended to increase belowground biomass, soil carbon, and soil nutrient contents. Experimental warming generally had neutral effects on the EMF of both alpine grasslands. Nevertheless, warming differentially affects the above- and belowground ecosystem functioning of Tibetan semi-arid alpine grasslands, with the aboveground EMF (AEMF) deceased but the belowground EMF (BEMF) increased under warmer conditions. Our results further showed that the negative effect of experimental warming on AEMF was mainly regulated by the changes of plant and soil biodiversity. However, plant productivity had a pivotal role in propelling the positive effect of warming on BEMF. Our results emphasized the potential impacts of plant and soil biodiversity, productivity, and soil nutrients in maintaining the EMF of alpine grasslands, which could offer novel views for sustainable management of Tibetan semi-arid alpine ecosystems.

Contribution of the bacterial community of poorly fermented oat silage to biogas emissions on the Qinghai Tibetan Plateau.

To better utilize poorly fermented oat silage on the Qinghai Tibetan Plateau, 239 samples of this biomass were collected from the plateau temperate zone (PTZ), plateau subboreal zone (PSBZ), and nonplateau climatic zone (NPCZ) in the region and analyzed for microbial community, chemical composition and in vitro gas production. Climatic factors affect the bacterial α-diversity and ß-diversity of poorly fermented oat silage, which led to the NPCZ having the highest relative abundance of Lactiplantibacillus plantarum. Furthermore, the gas production analysis showed that the NPCZ had the highest maximum cumulative gas emissions of methane. Through structural equation modeling analysis, environmental factors (solar radiation) affected methane emissions via the regulation of lactate production by L. plantarum. The enrichment of L. plantarum contributes to lactic acid production and thereby enhances methane emission from poorly fermented oat silage. Notably, there are many lactic acid bacteria detrimental to methane production in the PTZ. This knowledge will be helpful in revealing the mechanisms of environmental factors and microbial relationships influencing the metabolic processes of methane production, thereby providing a reference for the clean utilization of other poorly fermented silage.

Iron nanoparticles induced the growth and physio-chemical changes in Kobresia capillifolia seedlings.

Iron nanoparticles (NPs) priming is known to affect the seed germination and seedling growth in many plants. However, whether it has an important role in stimulating the growth of perennial Qinghai-Tibet Plateau plants remains unclear. In this study, the effects of seed priming with different concentrations of nFe2O3 and FeCl3 (10, 50, 100, 500, and 1000 mg L-1) on seed germination, plant growth, photosystem, antioxidant enzyme activities, root morphology, and biomass distribution of Kobresia capillifolia were evaluated under laboratory conditions. The results showed that compared with treatment materials, concentration had more significant effects on K. capillifolia development. There was no significant impact on germination rate were discovered under all treatments, but decreased the seed mildew rate at 100 mg L-1 nFe2O3. Compare with control, Fe-based priming significantly decreased root biomass. All Fe-based treatments increased rubisco activity of leaves, and significantly enhanced Pn at ranged from 10 to 100 mg L-1. Meanwhile, chlorophyll contents were decreased, the chloroplasts were swollen, and thylakoids were disorganized under all Fe treatments. Iron-based priming significantly enhanced SOD, POD, and CAT activities in Kobresia roots. In conclusion, the thick cuticle-covered seed coat of K. capillifolia postponed the penetration of FeNPs into seeds, so FeNPs priming had a weak impact on seed germination. The sustainable release of Fe ions from FeNPs and the uptake of Fe ions by roots affected the physiology, biochemistry and morphology of K. capillifolia. The findings of this study provide an in-depth understanding of how FeNPs impact the alpine meadow plant, K. capillifolia.

Draft genomes assembly and annotation of Carex parvula and Carex kokanica reveals stress-specific genes.

Kobresia plants are important forage resources on the Qinghai-Tibet Plateau and are essential in maintaining the ecological balance of grasslands. Therefore, it is beneficial to obtain Kobresia genome resources and study the adaptive characteristics of Kobresia plants on the Qinghai-Tibetan Plateau. Previously, we have assembled the genome of Carex littledalei (Kobresia littledalei), which is a diploid with 29 chromosomes. In this study, we assembled genomes of Carex parvula (Kobresia pygmaea) and Carex kokanica (Kobresia royleana) via using Illumina and PacBio sequencing data, which were about 783.49 Mb and 673.40 Mb in size, respectively. And 45,002 or 36,709 protein-coding genes were further annotated in the genome of C. parvula or C. kokanica. Phylogenetic analysis indicated that Kobresia in Cyperaceae separated from Poaceae about 101.5 million years ago after separated from Ananas comosus in Bromeliaceae about 117.2 million years ago. C. littledalei and C. parvula separated about 5.0 million years ago, after separated from C. kokanica about 6.2 million years ago. In this study, transcriptome data of C. parvula at three different altitudes were also measured and analyzed. Kobresia plants genomes assembly and transcriptome analysis will assist research into mechanisms of plant adaptation to environments with high altitude and cold weather.

Precipitation Alters the Effects of Temperature on the Ecosystem Multifunctionality in Alpine Meadows.

Precipitation and temperature are major controls on multiple ecosystem functions in alpine grasslands. There is scant evidence for the interactive effects of temperature and precipitation changes on the ecosystem multifunctionality (EMF) in alpine meadows. To explore the interactive effects of temperature and precipitation changes on the EMF in alpine meadows, we transplanted meadow blocks reciprocally among three altitudes (4,650, 4,950, and 5,200 m) on the central Tibetan Plateau. Compared with the home sites (control), the EMF has a trend to increase when meadow blocks were downward transplanted (experimental warming) to the high-precipitation sites but decrease as meadow blocks were downward transplanted to the low-precipitation sites. However, the experimental cooling (upward transplantation) consistently reduced the EMF regardless of the precipitation change. The increase of EMF under the experimental warming was closely related to the variation of both plant and soil functions, whereas the reduction of EMF under the cooling was highly correlated with the decrease of plant function. Our results highlight that climate warming effects on the EMF are greatly associated with precipitation changes in the semi-arid alpine ecosystems.

Genome sequence of Kobresia littledalei, the first chromosome-level genome in the family Cyperaceae.

Kobresia plants are important forage resources in the Qinghai-Tibet Plateau and are essential in maintaining the ecological balance of grasslands. Therefore, it is beneficial to obtain Kobresia genome resources and study the adaptive characteristics of Kobresia plants in the Qinghai-Tibetan Plateau. We assembled the genome of Kobresia littledalei C. B. Clarke, which was about 373.85 Mb in size. 96.82% of the bases were attached to 29 pseudo-chromosomes, combining PacBio, Illumina and Hi-C sequencing data. Additional investigation of the annotation identified 23,136 protein-coding genes. 98.95% of these were functionally annotated. According to phylogenetic analysis, K. littledalei in Cyperaceae separated from Poaceae about 97.6 million years ago after separating from Ananas comosus in Bromeliaceae about 114.3mya. For K. littledalei, we identified a high-quality genome at the chromosome level. This is the first time a reference genome has been established for a species of Cyperaceae. This genome will help additional studies focusing on the processes of plant adaptation to environments with high altitude and cold weather.