scholarly journals Responses of H. vulgare L. Seedlings to Basic Salt and Drought under Freeze-thaw Condition

2020 ◽  
Author(s):  
Wenyi Tang ◽  
Guozhang Bao ◽  
Bairu Yan ◽  
Yan Qu ◽  
Jiancai Guo ◽  
...  

Abstract Background Qinghai-Tibet Plateau is known for characteristics of high altitude, low rainfall and varying temperature, and the crops in this area are susceptible to abiotic stresses such as drought, basic salt and freeze-thaw that caused damages in different perspectives such as the permeability of biological membrane, osmotic adjustment, and antioxidant enzyme system. Hordeum vulgare L. is an indispensable crop in plateau and plays an important role in agricultural ecosystem as well.Result In this experiment, H. vulgare L. was used as experimental material and the physiological characteristics soluble protein (SP) content, malondialdehyde (MDA) content, antioxidant enzyme activity and relative water content (RWC) of seedlings were examined under freeze-thaw condition combined with drought and alkali stress.Conclusion Research results indicated that under the combined stresses of basic salt and drought, H. vulgare L. seedlings were damaged by lipid peroxidation, weakened superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities, while enhanced osmotic adjustment ability in plants cell. It was suggested that, in agricultural management, the simultaneous occurrence of two stresses, basic salt and drought, should be avoided in the early stage of H. vulgare L. planting to reduce the physiological stress on plants.

Author(s):  
Li Ning Wang ◽  
Mitsumine Fukui ◽  
Ichiyu Shou ◽  
Yutaka Yaguchi ◽  
Kazuhiko Funabiki ◽  
...  

2011 ◽  
Vol 47 (No. 1) ◽  
pp. 17-27 ◽  
Author(s):  
S. Tale Ahmad ◽  
R. Haddad

The effect of silicon (Si) was investigated on the major antioxidant enzyme activities including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), relative water content (RWC), chlorophyll and soluble protein contents, proline (Pro) and glycine betaine (GB) accumulation in three different growth stages (2<sup>nd</sup>, 4<sup>th</sup> leaf and tillering stages) of wheat (Triticum aestivum L.) plants under drought stress. The experiment was performed in a completely randomized design for three treatments including control, drought and Si-drought (2mM silicate sodium/kg) with three replications in a greenhouse. The results indicated that Si partially offset the negative impacts of drought stress increasing the tolerance of wheat by rising Pro and GB accumulation and soluble protein content. Compared with the plants treated with drought, applied Si significantly enhanced the activities of SOD, CAT, APX and POD. In contrast, drought stress caused a considerable decrease in RWC, chlorophyll and soluble protein contents. This Si effect was time-dependent and became stronger in the tillering stage. The results of the present experiment coincided with the conclusion that Si alleviates water deficit of wheat by preventing the oxidative membrane damage and may be associated with plant osmotic adjustment.


2015 ◽  
Vol 19 (2) ◽  
pp. 159-162 ◽  
Author(s):  
Rachel Asiniwasis ◽  
Maha T. Dutil ◽  
Scott Walsh

Background/Objectives The clinical and histopathologic findings of a rare simultaneous occurrence of papulonecrotic tuberculid and nodular tuberclid in a patient with active but asymptomatic pulmonary tuberculosis are presented. Papulonecrotic tuberculid was observed at a very early stage, presenting as molluscum-like lesions. This has been described once in the literature. This was observed in conjunction with lesions compatible with the rare clinicopathologic variant of nodular tuberculid. Critical to the diagnosis of active pulmonary tuberculosis was the use of induced sputum testing, which confirmed the diagnosis despite the lack of a cough and a chest x-ray negative for active tuberculosis. Methods/Results A 40-year-old male presented with a 2-week history of fever and a skin eruption consisting of molluscum-like papules on the ears, arms, and abdomen and nodules on his legs. Biopsies from both lesions were consistent with papulonecrotic and nodular tuberculid, respectively. Despite the lack of any respiratory symptoms, induced sputum grew Mycobacterium tuberculosis, and the lesions resolved on antituberculous therapy. Conclusions and Relevance Tuberculids are rare in Western countries but must be considered in the differential diagnosis of eruptions in patients from endemic countries. An active tuberculous focus must be sought out.


2016 ◽  
Vol 85 (2) ◽  
pp. 829-850 ◽  
Author(s):  
Shengbo Xie ◽  
Jianjun Qu ◽  
Xiangtian Xu ◽  
Yingjun Pang

2019 ◽  
Author(s):  
Junfeng Wang ◽  
Qingbai Wu ◽  
Ziqiang Yuan ◽  
Hojeong Kang

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.


2022 ◽  
Author(s):  
Zhang Wei ◽  
Guozhang Bao ◽  
Tang Wenyi ◽  
Dai Gejun ◽  
Xiao Jing ◽  
...  

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,


2020 ◽  
Vol 14 (9) ◽  
pp. 2835-2848
Author(s):  
Junfeng Wang ◽  
Qingbai Wu ◽  
Ziqiang Yuan ◽  
Hojeong Kang

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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