Simulating the role of gravel in freeze–thaw process on the Qinghai–Tibet Plateau

Abstract. Freezing and thawing action of the active layer plays a significant role in soil respiration (Rs) in permafrost regions. However, little is known about how the freeze-thaw process regulates the Rs dynamics in different stages for the alpine meadow underlain by permafrost on the Qinghai-Tibet Plateau (QTP). We conducted continuous in-situ measurements of Rs and freeze-thaw process of the active layer at an alpine meadow site in the Beiluhe permafrost region of QTP to determine the regulatory mechanisms of the different freeze-thaw stages of the active layer on the Rs. We found that the freezing and thawing process of active layer modified the Rs dynamics differently in different freeze-thaw stages. The mean Rs ranged from 0.56 to 1.75 μmol/m2s across the stages, with the lowest value in the SW stage and highest value in the ST stage; and Q10 among the different freeze-thaw stages changed greatly, with maximum (4.9) in the WC stage and minimum (1.7) in the SW stage. Patterns of Rs among the ST, AF, WC, and SW stages differed, and the corresponding contribution percentages of cumulative Rs to annual total Rs were 61.54, 8.89, 18.35, and 11.2 %, respectively. Soil temperature (Ts) was the most important driver of Rs regardless of soil water status in all stages. Our results suggest that as the climate warming and permafrost degradation continue, great changes in freeze-thaw process patterns may trigger more Rs emissions from this ecosystem because of prolonged ST stage.

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Barley Seedlings in Response to Salinity and Artemisinin Stress in the Present of Freeze-Thaw Stress

10.21203/rs.3.rs-1034052/v2 ◽

2022 ◽

Author(s):

Zhang Wei ◽

Guozhang Bao ◽

Tang Wenyi ◽

Dai Gejun ◽

Xiao Jing ◽

...

Keyword(s):

Artemisia Annua ◽

Soil Salinization ◽

Tibet Plateau ◽

Sod Activity ◽

Freeze Thaw ◽

Mda Content ◽

Use Efficiency ◽

Relative Electrical Conductivity ◽

Scavenging Efficiency ◽

Qinghai Tibet Plateau

Abstract In the Qinghai-Tibet Plateau, both the large daily temperature difference and soil salinization make plants susceptible to abiotic stresses such as freeze-thaw and salinity. Meanwhile, crops in this area could be subjected to the influence of artemisinin, an allelochemical exuded by Artemisia annua. In the context of freeze-thaw and salinity stresses, artemisinin was induced as an allelopathy stress factor to explore the physiological response of highland barley, including the relative electrical conductivity (RC), soluble protein (SP) content, malondialdehyde (MDA) content, antioxidant enzyme activity, and water use efficiency (WUE).There data suggested that artemisinin weakened the self-osmotic adjustment ability of seedlings, reducing the SOD activity in scavenging efficiency of reactive oxygen species, then causing oxidative damage to cell membrane of seedlings, which significantly increases the content of RC and MDA. Artemisinin stress can reduce the WUE of seedlings and weaken the photosynthesis intensity of seedlings as well. In a word, salinity stress and artemisinin respectively showed a synergistic compound relationship with freeze-thaw stress,

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Soil respiration of alpine meadow is controlled by freeze–thaw processes of active layer in the permafrost region of the Qinghai–Tibet Plateau

The Cryosphere ◽

10.5194/tc-14-2835-2020 ◽

2020 ◽

Vol 14 (9) ◽

pp. 2835-2848

Author(s):

Junfeng Wang ◽

Qingbai Wu ◽

Ziqiang Yuan ◽

Hojeong Kang

Keyword(s):

Soil Respiration ◽

Active Layer ◽

Alpine Meadow ◽

Tibet Plateau ◽

Permafrost Region ◽

Permafrost Degradation ◽

Freeze Thaw ◽

Thaw Cycle ◽

Freeze Thaw Cycle ◽

Qinghai Tibet Plateau

Abstract. Freezing and thawing action of the active layer plays a significant role in soil respiration (Rs) in permafrost regions. However, little is known about how the freeze–thaw processes affect the Rs dynamics in different stages of the alpine meadow underlain by permafrost in the Qinghai–Tibet Plateau (QTP). We conducted continuous in situ measurements of Rs and freeze–thaw processes of the active layer at an alpine meadow site in the Beiluhe permafrost region of the QTP and divided the freeze–thaw processes into four different stages in a complete freeze–thaw cycle, comprising the summer thawing (ST) stage, autumn freezing (AF) stage, winter cooling (WC) stage, and spring warming (SW) stage. We found that the freeze–thaw processes have various effects on the Rs dynamics in different freeze–thaw stages. The mean Rs ranged from 0.12 to 3.18 µmol m−2 s−1 across the stages, with the lowest value in WC and highest value in ST. Q10 among the different freeze–thaw stages changed greatly, with the maximum (4.91±0.35) in WC and minimum (0.33±0.21) in AF. Patterns of Rs among the ST, AF, WC, and SW stages differed, and the corresponding contribution percentages of cumulative Rs to total Rs of a complete freeze–thaw cycle (1692.98±51.43 g CO2 m−2) were 61.32±0.32 %, 8.89±0.18 %, 18.43±0.11 %, and 11.29±0.11 %, respectively. Soil temperature (Ts) was the most important driver of Rs regardless of soil water status in all stages. Our results suggest that as climate change and permafrost degradation continue, great changes in freeze–thaw process patterns may trigger more Rs emissions from this ecosystem because of a prolonged ST stage.

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Characterization of the Rickettsia-like and Coxiella-like symbionts in the tick Dermacentor everestianus Hirst, 1926 (Acari: Ixodidae) from the Qinghai-Tibet Plateau

Systematic and Applied Acarology ◽

10.11158/saa.24.1.8 ◽

2019 ◽

Vol 24 (1) ◽

pp. 106

Author(s):

Ningxin Li ◽

Sisi Li ◽

Duo Wang ◽

Peng Yan ◽

Wenying Wang ◽

...

Keyword(s):

Salivary Glands ◽

Malpighian Tubules ◽

Tibet Plateau ◽

The Tibetan Plateau ◽

Anaplasma Ovis ◽

Dermacentor Everestianus ◽

Qinghai Tibet Plateau ◽

Great Damage

The tick Dermacentor everestianus is widely distributed on the Tibetan Plateau of China, where adult ticks usually parasitize sheep, yaks and horses. D. everestianus is able to transmit many zoonotic pathogens, including Francisella tularensis, Anaplasma ovis and Rickettsia raoultii-like bacteria, and can cause great damage to animals and human health. However, the symbionts in D. everestianus have not yet been investigated, which has hindered our understanding of the relationships between this tick species and associated tick-borne pathogens. In the current study, the Rickettsia-like and Coxiella-like symbionts in D. everestianus were identified and characterized. The results indicated that both Rickettsia-like (RLS-Des) and Coxiella-like (CLS-Des) symbionts showed 100% infection rates and displayed vertical transmission in D. everestianus. The RLS-Des showed a relatively higher abundance than the CLS-Des in D. everestianus. No tissue specificity was found for the RLS-Des or CLS-Des. These symbionts can inhabit the ovaries, salivary glands, midguts, Malpighian tubules and testes of D. everestianus. During the development of D. everestianus, the density of the RLS-Des showed more obvious changes than did that of the CLS-Des. Dramatic changes in the density of the RLS-Des were detected in the midguts, ovaries, salivary glands and Malpighian tubules when female D. everestianus were engorged and detached from the host, which suggested the potential role of these symbionts in the reproduction and development of D. everestianus. The dynamic changes in the density of the CLS-Des during feeding and reproduction of D. everestianus suggest the involvement of the CLS-Des in the reproduction of D. everestianus.

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Comparisons of lung and gluteus transcriptome profiles between yaks at different ages

Scientific Reports ◽

10.1038/s41598-019-50618-x ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Jin-Wei Xin ◽

Zhi-Xin Chai ◽

Cheng-Fu Zhang ◽

Qiang Zhang ◽

Yong Zhu ◽

...

Keyword(s):

Immune System ◽

Immune Function ◽

Muscle Injury ◽

Tibet Plateau ◽

Immune Functions ◽

Immune System Activation ◽

System Activation ◽

Qinghai Tibet Plateau ◽

Activation Status

Abstract The yak, Bos grunniens, is the only large mammal in the Qinghai-Tibet Plateau and has been bred to provide meat, milk, and transportation. Previous studies indicate that the immune system contributes to the yak’s adaptation to high-altitude environments. In order to further investigate changes in immune function during yak development, we compared the transcriptome profiles of gluteus and lung tissues among yaks at 6, 30, 60, and 90 months of age. Analyses of significantly differentially expressed genes (DEGs) in lung tissues revealed that immune function was more activated at 6-months and less activated at 90-months than in the 30 and 60-month-old animals. DEG exploration in gluteal tissues revealed that immune functions were more highly activated at both 6 and 90-months, compared with 30 and 60-months. Immune system activation in the muscle and lung tissues of 30-month-old yaks may increase their resistance to infections, while decreased may be due to aging. Furthermore, the higher immune activation status in the gluteal tissues in 90-month-old yaks could be due to muscle injury and subsequent regeneration, which is supported by the fact that 5 unigenes related with muscle injury and 3 related to muscle regeneration displayed greater expression levels at 90-months than at 30 and 60-months. Overall, the present study highlights the important role of the immune system in yak development, which will facilitate future investigations.

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