scholarly journals Comparative study of silicon and selenium to modulate chloroplast pigments levels, Hill activity, photosynthetic parameters and carbohydrate metabolism under arsenic stress in rice seedlings

Author(s):  
Susmita Das ◽  
Asok K. Biswas

Abstract Arsenic (As) in groundwater severely harms global economic development by affecting growth and productivity of agricultural crops that causes human health risk. The comparative influence of silicon (Si) and selenium (Se) to modulate pigments levels, photosynthetic parameters using LI-6400XT Portable Photosynthesis System and carbohydrate metabolism under arsenate (As-V) stress in rice cv. MTU-1010 were evaluated. As(V) stress significantly decreased chlorophyll-a (32% on an average), chlorophyll-b (58% on an average), total chlorophyll (46% on an average), fluorescence intensity (31% on an average),, carotene (39% on an average), xanthophyll (33% on an average), Hill activity (47% on an average) and the photosynthetic parameters viz., intercellular-CO2-concentration (52% on an average), net photosynthesis (54% on an average), transpiration rate (36% on an average) and stomatal conductance (38% on an average) in the test seedlings. As(V) + Si treatments enhanced the said parameters more than As(V) + Se treatments in rice seedlings. Sugar contents viz., reducing (85% on an average) and non-reducing sugar (61% on an average) were increased but starch content (57% on an average) was decreased in As(V) treated seedlings. The activities of carbohydrate metabolizing enzymes were increased, while sucrose synthase activity was decreased due to As(V) toxicity in the test seedlings. Co-application of Si and As(V) as well as Se and As(V) showed ameliorative effects on the said parameters but more potential effect was observed under combined application of Si and As(V) in rice seedlings. Thus, the present study is focused to highlight the comparative capability of Si and Se to ameliorate the As induced toxic effects on chloroplast pigments, photosynthetic activities and sugar metabolism in rice seedlings which will be an effective approach to develop possible strategies in As contaminated agricultural soil to improve normal growth and productivity of rice plants.

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 560
Author(s):  
José A. Hernández ◽  
Pedro Díaz-Vivancos ◽  
José Ramón Acosta-Motos ◽  
Nuria Alburquerque ◽  
Domingo Martínez ◽  
...  

(1) Background: Prunus species have the ability to suspend (induce dormancy) and restart growth, in an intricate process in which environmental and physiological factors interact. (2) Methods: In this work, we studied the evolution of sugars, antioxidant metabolism, and abscisic acid (ABA) and gibberellins (GAs) levels during bud dormancy evolution in a high-chill peach variety, grown for two seasons in two different geographical areas with different annual media temperature, a cold (CA) and a temperate area (TA). (3) Results: In both areas, starch content reached a peak at ecodormancy, and then decreased at dormancy release (DR). Sorbitol and sucrose declined at DR, mainly in the CA. In contrast, glucose and fructose levels progressively rose until DR. A decline in ascorbate peroxidase, dehydroascorbate reductase, superoxide dismutase and catalase activities occurred in both seasons at DR. Moreover, the H2O2-sensitive SOD isoenzymes, Fe-SOD and Cu,Zn-SOD, and two novel peroxidase isoenzymes, were detected. Overall, these results suggest the occurrence of a controlled oxidative stress during DR. GA7 was the major bioactive GA in both areas, the evolution of its levels being different between seasons and areas. In contrast, ABA content decreased during the dormancy period in both areas, resulting in a reduction in the ABA/total GAs ratio, being more evident in the CA. (4) Conclusion: A possible interaction sugars-hormones-ROS could take place in high-chill peach buds, favoring the DR process, suggesting that, in addition to sugar metabolism, redox interactions can govern bud DR, regardless of chilling requirements.


2001 ◽  
Vol 44 (1) ◽  
pp. 59-62 ◽  
Author(s):  
Luiz Carlos de Oliveira Lima ◽  
Adimilson Bosco Chitarra ◽  
Maria Isabel F. Chitarra

Changes in amylase activity, starch and reducing and non-reducing sugars contents were monitored during ripening of mango fruits (Mangifera indica L.). The climateric raising in mango fruit is marked by an appreciable increase in the activity of amylase, reducing and non-reducing sugars contents and decrease in the starch content. The fruit affected with spongy tissue exhibited much lower amylase activity and reducing and non-reducing sugars, but exhibited much higher starch content during storage at 12 ± 2° C and 90 ± 5% RH for 28 days, when compared to healthy tissue of ‘Tommy Atkins’. Whether this is caused due to adverse effects on certain enzyme activities during ripening is not clearly known. These dates showed that carbohydrate metabolism is an important feature during ripening of mango.


2020 ◽  
Vol 8 (10) ◽  
pp. 1565 ◽  
Author(s):  
Abraham Mulu Oljira ◽  
Tabassum Hussain ◽  
Tatoba R. Waghmode ◽  
Huicheng Zhao ◽  
Hongyong Sun ◽  
...  

Soil salinity is one of the most important abiotic stresses limiting plant growth and productivity. The breeding of salt-tolerant wheat cultivars has substantially relieved the adverse effects of salt stress. Complementing these cultivars with growth-promoting microbes has the potential to stimulate and further enhance their salt tolerance. In this study, two fungal isolates, Th4 and Th6, and one bacterial isolate, C7, were isolated. The phylogenetic analyses suggested that these isolates were closely related to Trichoderma yunnanense, Trichoderma afroharzianum, and Bacillus licheniformis, respectively. These isolates produced indole-3-acetic acid (IAA) under salt stress (200 mM). The abilities of these isolates to enhance salt tolerance were investigated by seed coatings on salt-sensitive and salt-tolerant wheat cultivars. Salt stress (S), cultivar (C), and microbial treatment (M) significantly affected water use efficiency. The interaction effect of M x S significantly correlated with all photosynthetic parameters investigated. Treatments with Trichoderma isolates enhanced net photosynthesis, water use efficiency and biomass production. Principal component analysis revealed that the influences of microbial isolates on the photosynthetic parameters of the different wheat cultivars differed substantially. This study illustrated that Trichoderma isolates enhance the growth of wheat under salt stress and demonstrated the potential of using these isolates as plant biostimulants.


1995 ◽  
Vol 108 (2) ◽  
pp. 735-741 ◽  
Author(s):  
L. Guglielminetti ◽  
P. Perata ◽  
A. Alpi

2021 ◽  
Author(s):  
Jing Su ◽  
Chunxia Zhang ◽  
Lingcheng Zhu ◽  
Nanyang Yang ◽  
Jingjing Yang ◽  
...  

Abstract Background: Cellulose is not only a common component in vascular plants, but also has great economic benefits for paper, wood, and industrial products. And its biosynthesis is highly regulated by carbohydrate metabolism and allocation in plant. MdFRK2, which encodes a key fructokinase (FRK) in apple, showed especially high affinity to fructose and regulated carbohydrate metabolism. Results: It was observed that overexpression of MdFRK2 in apple decreased sucrose (Suc) and fructose (Fru) with augmented FRK activity in stems, and caused the alterations of many phenotypic traits that include increased cellulose content and thickened primary phloem. To further investigate the involved mechanisms, we generated FRK2-OE poplar lines OE#1, OE#4 and OE#9 and discovered (1) a direct metabolic pathway for the biosynthesis of cellulose is that increased cleavage of Suc into UDP-glucose (UDPG) for cellulose synthesis via the increased sucrose synthase (SUSY) activity and transcript levels of PtrSUSY1, (2) another finding of this study is that overexpression of MdFRK2 resulted in the huge increased cellulose level by shifting the fructose 6-phosphate or glucose 6-phsophate towards UDPG formation, (3) that with increased UDPG in the sink tissue, and therefore more cellulose or hemicellulose can be used to thicker primary phloem. These results demonstrated that MdFRK2 overexpression would significantly changes the photosynthetic carbon flux from sucrose and hexose to UDPG for increased cellulose synthesis.Conclusions: The present data indicated that MdFRK2 overexpression in apple and poplar changes the photosynthetic carbon flux from sucrose and hexose to UDPG for stem cellulose synthesis. A new strategy is proposed to increase cellulose production by regulating sugar metabolism as a whole.


2019 ◽  
Vol 49 (7) ◽  
pp. 752-758
Author(s):  
Martin-Michel Gauthier ◽  
Douglass F. Jacobs

The influence of water deficits and drought on tree physiological processes, growth, and survival has been the focus of substantial research efforts and debate over the past decades, but there is still a need to quantitatively link finer scale mechanistic explanations of the influence of water status with the physiological responses of trees, particularly for those past the sapling stage. Hence, the objective of this study was to link accumulated water stress during the growing season to leaf physiological response mechanisms of Juglans nigra L. trees. Results showed that trees subjected to higher cumulative water stress had lower maximum light-saturated photosynthesis (Amax), initiated net photosynthesis at higher light levels (Ic), and displayed reduced effectiveness of CO2 fixation per photons absorbed (Qe) at the bottom and upper positions along the vertical canopy gradient. Results suggest that water stress integral (Sψ), a variable that takes into account accumulated water deficits, would be useful to help future research efforts aimed at investigating responses to drought in trees past the sapling stage.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jinchao Gao ◽  
Fahd S Alotaibi ◽  
Ragab Ibrahim. Ismail

Abstract Carbohydrate metabolism can provide energy for human exercise. However, different exercise intensities will consume different amounts of energy. For this reason, the paper uses a fractional linear regression equation to study the characteristics of carbohydrate metabolism and energy consumption of other groups of human beings with the same oxygen consumption during exercise. In addition, the thesis measures energy consumption during exercise and body recovery by analyzing gas metabolism methods. As a result, we found that the sugar, fat metabolism, and energy consumption of heavier volunteers under the same exercise intensity were lower than those of regular weight volunteers. Thus, the fractional linear regression method can help us analyze the relationship between glucose metabolism and exercise energy.


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