scholarly journals Exogenous Spermidine Priming Mitigates the Osmotic Damage in Germinating Seeds of Leymus chinensis Under Salt-Alkali Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Chen Hongna ◽  
Shi Junmei ◽  
Tao Leyuan ◽  
Han Xiaori ◽  
Lin Guolin ◽  
...  

Spermidine (Spd) is known to protect macromolecules involved in physiological and biochemical processes in plants. However, it is possible that Spd also plays an osmotic regulatory role in promoting the seed germination of Leymus chinensis (L. chinensis) under salt-alkali stress. To investigate this further, seeds of L. chinensis were soaked in Spd solution or distilled water, and a culture experiment was performed by sowing the soaked seeds in saline-alkaline soils. The data showed that the Spd priming resulted in an increase of more than 50% in soluble sugar content and an increase of more than 30% in proline content in the germinating seeds. In addition, the Spd priming resulted in an increase of more than 30% in catalase activity and an increase of more than 25% in peroxidase activity in the germinating seeds and effectively mitigated the oxidative damage to the plasma membrane in the germinating seeds under salt-alkali stress. Moreover, the Spd priming of seeds affected the accumulation of polyamine (PA) and maintained the activities of macromolecules involved in physiological metabolism in germinating seeds exposed to salt-alkali stress. Furthermore, the Spd priming treatment increased the hydrogen peroxide (H2O2) level to more than 30% and the Ca2+ concentration to more than 20% in the germinating seeds, thus breaking the dormancy induction pathways in L. chinensis seeds through beneficial hormone enrichment. This study provides an insight into the Spd-mediated regulation pathway during exogenous Spd priming of L. chinensis seeds, which mitigates osmotic and oxidative damage and maintains the integrality of the cell lipid membrane. Thus, exogenous Spd priming increases PA oxidase activity and maintains the accumulation of H2O2. We found that the H2O2 beneficially affected the balance of Ca2+ and hormones, promoting the vigor and germination of L. chinensis in response to salt-alkali stress.

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Xiaoyu Li ◽  
Junfeng Wang ◽  
Jixiang Lin ◽  
Ying Wang ◽  
Chunsheng Mu

Leymus chinensishas extensive ecological adaptability and can grow well in saline-alkaline soils. The knowledge about tolerance mechanisms ofL. chinensiscould be base for utilization of saline-alkaline soils and grassland restoration and rebuilding. Two neutral salts (NaCl : Na2SO4= 9 : 1) and two alkaline salts (NaHCO3 : Na2CO3= 9 : 1) with concentration of 0, 100, and 200 mmol/L were used to treat potted 35-day-old seedlings with rhizome growth, respectively. After 10 days, the biomass and number of daughter shoots all decreased, with more reduction in alkali than in salt stress. The rhizome biomass reduced more than other organs. The number of daughter shoots from rhizome was more than from tillers. Under both stresses, Na+contents increased more in rhizome than in other organs; the reduction of K+content was more in underground than aerial tissue. Anion ions or organic acids were absorbed to neutralize cations. Na+content in stem and leaf increased markedly in high alkalinity (200 mmol/L), with accumulation of soluble sugar and organic acids sharply. Rhizomes helpL. chinensisto adapt to saline and low alkaline stresses by transferring Na+. However, rhizomes lost the ability to prevent Na+transport to aerial organs under high alkalinity, which led to severe growth inhibition ofL. chinensis.


2014 ◽  
Vol 1010-1012 ◽  
pp. 1225-1229
Author(s):  
Ming Xia Zhu ◽  
Feng Jin ◽  
Xi Wen Shao ◽  
Xian Ying Gao ◽  
Yan Qiu Geng ◽  
...  

Taking Changbai 9 and Changbai 22 as experiment material, using pot experiment, to study of different concentration effect of saline alkali stress on physiological characteristics of rice in different growth periods. The results showed that, effect of saline alkali stress on the physiological characteristics of the same rice variety and soil characteristics of different resistant rice varieties are different. Weak salt resistance of Changbai 22 of chlorophyll , soluble sugar and MDA of salt stress more sensitive than saline resistance strong of Changbai 9,and the change trend of the physiological indexes of two cultivars under saline alkali stress is consistent, with the increasing concentration of salt stress, leaf chlorophyll content, soluble sugar content and soluble protein content firstly increased and then decreased,while the MDA concentration showed an increasing trend. At the same time with the increase of salt stress concentration, accumulation of soluble sugar in leaves of Changbai 9 increased even more than Changbai 22,indicating the Changbai 9 may be mainly through the accumulation of soluble sugar to alleviate the toxic effects of osmotic stress. This study can be used as an important reference index for soda saline alkali soil rice planting, soil improvement and comprehensive utilization.


2019 ◽  
Vol 17 (1) ◽  
pp. 1352-1360 ◽  
Author(s):  
Huijuan Guo ◽  
Zhiqiang Hu ◽  
Huimin Zhang ◽  
Wei Min ◽  
Zhenan Hou

AbstractThis pot experiment was to evaluate how salts (NaCl, Na2SO4) and alkali (Na2CO3+NaHCO3) affect the physiological and biochemical characteristics during the seedling stage of two cotton cultivars (salt-tolerant, L24; salt-sensitive, X45). Salt and alkali stress reduced seedling emergence rate, relative biomass, and chlorophyll content, however, the REC and MDA content increased. Salt and alkali stress increased markedly superoxide dismutase (SOD) activity. Peroxidase (POD) activity increased first and then decreased as the increase of salt and alkali stress. Catalase (CAT) activity initially increased and then decreased as NaCl stress increased. In addition, the SOD activity, REC, and MDA content was markedly higher in salt stress than that in alkali stress. The proline content of L24 was higher than that of X45 under salt and alkali stress. However, glycine betaine and soluble sugar content of L24 was lower than that of X45 under alkali stress. The REC and MDA content of L24 were lower than those of X45, however, the relative biomass, chlorophyll content, SOD, POD, CAT, and Pro were higher than those of X45. In conclusion, salt tolerant cotton cultivars may possess a superior protection effect by increasing antioxidant enzymes activity under salt and alkali stress.


2021 ◽  
Vol 22 (4) ◽  
pp. 1562
Author(s):  
Jia Zhao ◽  
Wenjun Li ◽  
Shan Sun ◽  
Liling Peng ◽  
Zhibo Huang ◽  
...  

Seed vigor affects seed germination and seedling emergence, and therefore is an important agronomic trait in rice. Small auxin-up RNAs (SAURs) function in a range of developmental processes, but their role in seed vigor remains unclear. Here, we observed that disruption of OsSAUR33 resulted in reduced germination rates and low seed uniformity in early germination. Expression of OsSAUR33 was higher in mature grains and early germinating seeds. RNA-seq analysis revealed that OsSAUR33 modulated seed vigor by affecting the mobilization of stored reserves during germination. Disruption of OsSAUR33 increased the soluble sugar content in dry mature grains and seeds during early germination. OsSAUR33 interacted with the sucrose non-fermenting-1-related protein kinase OsSnRK1A, a regulator of the sugar signaling pathway, which influences the expression of sugar signaling-related genes during germination. Disruption of OsSAUR33 increased sugar-sensitive phenotypes in early germination, suggesting OsSAUR33 likely affects seed vigor through the sugar pathway. One elite haplotype of OsSAUR33 associated with higher seed vigor was identified mainly in indica accessions. This study provides insight into the effects of OsSAUR33 on seed vigor in rice.


2019 ◽  
Vol 70 (11) ◽  
pp. 1004 ◽  
Author(s):  
Congcong Zheng ◽  
Huimin Ma ◽  
Yingzhi Gao ◽  
Hao Sun ◽  
Haijun Yang ◽  
...  

Soil salinisation and overgrazing are two important factors limiting plant growth in the Songnen Grassland, Northeast China. Leymus chinensis, a dominant rhizomatous grass, resists grazing and tolerates saline–alkali stress. However, its adaptive mechanisms to the dual effects of grazing and saline–alkali stress remain largely unknown. A two-factorial field experiment was conducted in two consecutive years in the natural L. chinensis community, combining the addition of mixed saline–alkali solution (NaCl:NaHCO3:Na2CO3 1:1:1, amount 559.13 g m–2 year–1) with clipping (removal of 60% of aboveground biomass, AGB). Saline–alkali addition significantly increased AGB and total biomass in the no clipping but not in the clipping treatment. Irrespective of clipping, ramet density was significantly decreased, and individual ramet biomass was significantly increased under salt stress. The significant increase in AGB was due to a high K+:Na+ ratio, high water-use efficiency, and an increase in leaf area index and net photosynthesis rate of individual ramets under salt–alkali stress. Clipping significantly decreased AGB and total biomass regardless of saline–alkali addition, possibly because of decreased sugar content of rhizomes. Saline–alkali and clipping had an interactive effect on AGB and total biomass of L. chinensis. The significant reduction in AGB and total biomass were mainly caused by reduced proline and water-soluble carbohydrate content under dual stress. A modified and simplified graphic model of the limiting resource model was proposed based on our results. Leymus chinensis can grow well under saline–alkali stress via ramet biomass compensation, in which the significant decrease in ramet density is compensated by the significant increase in individual ramet biomass. Ramet compensation and clonal integration were identified to be main mechanisms of herbivory and saline–alkali tolerance.


2018 ◽  
Vol 5 (03) ◽  
Author(s):  
ARADHNA KUMARI ◽  
IM KHAN ◽  
ANIL KUMAR SINGH ◽  
SANTOSH KUMAR SINGH

Poplar clone Kranti was selected to assess the morphological, physiological and biochemical responses under drought at different levels of water stress, as it is a common clone used to be grown in Uttarakhand for making paper and plywood. The cuttings of Populus deltoides L. (clone Kranti) were exposed to four different watering regimes (100, 75, 50 and 25% of the field capacity) and changes in physiological and biochemical parameters related with drought tolerance were recorded. Alterations in physiological (i.e. decrease in relative water content) and biochemical parameters (i.e. increase in proline and soluble sugar content and build-up of malondialdehyde by-products) occurred in all the three levels of water stress, although drought represented the major determinant. Drought treatments (75%, 50% and 25% FC) decreased plant height, radial stem diameter, harvest index, total biomass content and RWC in all the three watering regimes compared to control (100% FC). Biochemical parameters like proline, soluble sugar and MDA content increased with severity and duration of stress, which helped plants to survive under severe stress. It was analyzed that for better wood yield poplar seedlings should avail either optimum amount of water (amount nearly equal to field capacity of soil) or maximum withdrawal up to 75% of field capacity up to seedling establishment period (60 days). Furthermore, this study manifested that acclimation to drought stress is related with the rapidity, severity, and duration of the drought event of the poplar species.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hongyi Zhao ◽  
Juelan Guan ◽  
Qing Liang ◽  
Xueyuan Zhang ◽  
Hongling Hu ◽  
...  

AbstractThe effects of cadmium stress on the growth and physiological characteristics of Sassafras tzumu Hemsl. were studied in pot experiments. Five Cd levels were tested [CT(Control Treatment) : 0 mg/kg, Cd5: 5 mg/kg, Cd20: 20 mg/kg, Cd50: 50 mg/kg, and Cd100: 100 mg/kg]. The growth and physiological characteristics of the sassafras seedlings in each level were measured. The results showed that soil Cd had negative influences on sassafras growth and reduced the net growth of plant height and the biomass of leaf, branch and root. Significant reductions were recorded in root biomass by 18.18%(Cd5), 27.35%(Cd20), 27.57%(Cd50) and 28.95%(Cd100). The contents of hydrogen peroxide decreased first then increased while malondialdehyde showed the opposite trend with increasing cadmium concentration. Decreases were found in hydrogen peroxide contents by 10.96%(Cd5), 11.82%(Cd20) and 7.02%(Cd50); increases were found in malondialdehyde contents by 15.47%(Cd5), 16.07%(Cd20) and 7.85%(Cd50), indicating that cadmium stress had a certain effect on the peroxidation of the inner cell membranes in the seedlings that resulted in damage to the cell membrane structure. Superoxide dismutase activity decreased among treatments by 17.05%(Cd5), 10,68%(Cd20), 20.85%(Cd50) and 8.91%(Cd100), while peroxidase activity increased steadily with increasing cadmium concentration; these results suggest that peroxidase is likely the main protective enzyme involved in the reactive oxygen removal system in sassafras seedlings. Upward trends were observed in proline content by 90.76%(Cd5), 74.36%(Cd20), 99.73%(Cd50) and 126.01%(Cd100). The increase in proline content with increasing cadmium concentration indicated that cadmium stress induced proline synthesis to resist osmotic stress in the seedlings. Compared to that in CT, the soluble sugar content declined under the different treatments by 32.84%(Cd5), 5.85%(Cd20), 25.55%(Cd50) and 38.69%(Cd100). Increases were observed in the soluble protein content by 2.34%(Cd5), 21.36%(Cd20), 53.15%(Cd50) and 24.22%(Cd100). At different levels of cadmium stress, the chlorophyll content in the seedlings first increased and then decreased, and it was higher in the Cd5 and Cd20 treatments than that in the CT treatment. These results reflected that cadmium had photosynthesis-promoting effects at low concentrations and photosynthesis-suppressing effects at high concentrations. The photosynthetic gas exchange parameters and photosynthetic light-response parameters showed downward trends with increasing cadmium concentration compared with those in CT; these results reflected the negative effects of cadmium stress on photosynthesis in sassafras seedlings.


Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1313
Author(s):  
Md. Jahirul Islam ◽  
Byeong Ryeol Ryu ◽  
Md. Obyedul Kalam Azad ◽  
Md. Hafizur Rahman ◽  
Md. Soyel Rana ◽  
...  

The effect of exogenously applied putrescine (Put) on salt stress tolerance was investigated in Panax ginseng. Thirty-day-old ginseng sprouts were grown in salinized nutrient solution (150 mM NaCl) for five days, while the control sprouts were grown in nutrients solution. Putrescine (0.3, 0.6, and 0.9 mM) was sprayed on the plants once at the onset of salinity treatment, whereas control plants were sprayed with water only. Ginseng seedlings tested under salinity exhibited reduced plant growth and biomass production, which was directly interlinked with reduced chlorophyll and chlorophyll fluorescence due to higher reactive oxygen species (hydrogen peroxide; H2O2) and lipid peroxidation (malondialdehyde; MDA) production. Application of Put enhanced accumulation of proline, total soluble carbohydrate, total soluble sugar and total soluble protein. At the same time, activities of antioxidant enzymes like superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase in leaves, stems, and roots of ginseng seedlings were increased. Such modulation of physio-biochemical processes reduced the level of H2O2 and MDA, which indicates a successful adaptation of ginseng seedlings to salinity stress. Moreover, protopanaxadiol (PPD) ginsenosides enhanced by both salinity stress and exogenous Put treatment. On the other hand, protopanaxatriol (PPT) ginsenosides enhanced in roots and reduced in leaves and stems under salinity stress condition. In contrast, they enhanced by exogenous Put application in all parts of the plants for most cases, also evidenced by principal component analysis. Collectively, our findings provide an important prospect for the use of Put in modulating salinity tolerance and ginsenosides content in ginseng sprouts.


2011 ◽  
Vol 356-360 ◽  
pp. 2763-2766 ◽  
Author(s):  
Yang Fan Gao ◽  
Ming Wang Shi ◽  
Jian Hua Wang

In this article, we studied to different concentrations of MCPA to creeping bentgrass Growth. Through the creeping bentgrass in four different periods of chlorophyll content, MDA and soluble sugar content determination. This test result showed:With the MCPA concentration increases, creeping bentgrass decline of chlorophyll content in the same period of growth, MDA and soluble sugar content increased. MCPA used after the early pair of creeping bentgrass growth is large, to put off with MCPA handle time, to affect to creeping bentgrass growth is gradually decreased.


Archaea ◽  
2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Yendi E. Navarro-Noya ◽  
César Valenzuela-Encinas ◽  
Alonso Sandoval-Yuriar ◽  
Norma G. Jiménez-Bueno ◽  
Rodolfo Marsch ◽  
...  

In this study the archaeal communities in extreme saline-alkaline soils of the former lake Texcoco, Mexico, with electrolytic conductivities (EC) ranging from 0.7 to 157.2 dS/m and pH from 8.5 to 10.5 were explored. Archaeal communities in the 0.7 dS/m pH 8.5 soil had the lowest alpha diversity values and were dominated by a limited number of phylotypes belonging to the mesophilic CandidatusNitrososphaera. Diversity and species richness were higher in the soils with EC between 9.0 and 157.2 dS/m. The majority of OTUs detected in the hypersaline soil were members of the Halobacteriaceae family. Novel phylogenetic branches in the Halobacteriales class were detected in the soil, and more abundantly in soil with the higher pH (10.5), indicating that unknown and uncharacterized Archaea can be found in this soil. Thirteen different genera of the Halobacteriaceae family were identified and were distributed differently between the soils.Halobiforma,Halostagnicola,Haloterrigena, andNatronomonaswere found in all soil samples. Methanogenic archaea were found only in soil with pH between 10.0 and 10.3. Retrieved methanogenic archaea belonged to the Methanosarcinales and Methanomicrobiales orders. The comparison of the archaeal community structures considering phylogenetic information (UniFrac distances) clearly clustered the communities by pH.


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