Potassium plays a significant role in the basic functions of plant growth and development. Potassium uptake is closely associated with morphological characteristics of the roots. However, the dynamic characteristics of phenotype and lifespan of cotton ( Gossypium hirsutum L.) lateral roots and root hairs under low and high potassium stress remain unclear. In this study, potassium stress experiments (low and high potassium, medium potassium as control) were conducted using RhizoPot (an in situ root observation device) to determine the response characteristics of lateral roots and root hairs in cotton under potassium stress. The plant morphology, photosynthetic characteristics, root phenotypic changes, and lifespan of lateral roots and root hairs were measured. Potassium accumulation, aboveground phenotype, photosynthetic capacity, root length density, root dry weight, root diameter, lateral root lifespan, and root hair lifespan under low potassium stress were significantly decreased compared to medium potassium treatment. However, the root hair length of the former was significantly increased than that of the latter. Potassium accumulation and the lateral root lifespan were significantly increased under high potassium treatment, while root length density, root dry weight, root diameter, root hair length, and root hair lifespan were significantly decreased compared to the medium potassium treatment. Notably, there were no significant differences in aboveground morphology and photosynthetic characters. Principal component analysis revealed that lateral root lifespan, root hair lifespan of the first lateral root, and root hair length significantly correlated with potassium accumulation. The root had similar regularity responses to low and high potassium stress except for lifespan and root hair length. The findings of this study enhance the understanding of the phenotype and lifespan of cotton’s lateral roots and root hairs under low and high potassium stress.
This study evaluated the therapeutic efficacy of Schisandrin A on systemic colibacillosis of chickens. One hundred and eighty, 1-day-old Hailan Brown chickens were divided into 6 groups of 30 chickens each and assigned to the following treatments: 1) uninfected/untreated control; 2) infected Escherichia coli; 3) infected-plus low dose of Schisandrin A therapy (50 mg/kg); 4) infected-plus medium dose of Schisandrin A therapy (100 mg/kg); 5) infected-plus high dose of Schisandrin A therapy (200 mg/kg) and 6) infected-plus antimicrobial therapy (florfenicol). Each group of chickens was placed in cages with a photoperiod of 12 h of light and 12 h of dark. Feed and water for all groups were provided ad libitum for the duration of the study. On d 14, all the chickens except the uninfected control group were intraperitoneally inoculated with a fresh culture of E. coli containing 1 × 108 CFU/mL. The parameters measured included: average daily weight gain (ADG), percent survivability, liver index, serum activity of enzymes (ALT and AST), hepatic and intestinal concentrations of TNF-α, IL-1β, IL-6, IL-8, and LPS, expression of tight junction proteins (occludin, ZO-1, and claudin-1), relative abundance of bacterial species and histopathological changes in hepatic and intestinal tissue. The results showed that the medium and high doses of Schisandrin A ameliorated the detrimental effects of colibacillosis on weight gain. Regarding organ indexes, E. coli infection induced a significant increase in liver index, all the doses of Schisandrin A produced a significant reduction of liver index in comparison to the E. coli infected control. Serum activity of ALT and AST enzymes significantly increased due to E. coli infection, with the exception of the low dose of Schisandrin A for AST enzyme activity, all the Schisandrin A treatments significantly lowered enzyme activity in comparison to the E. coli infected control. Regarding concentrations of inflammatory markers in hepatic and intestinal, E. coli infection caused a significant increase in TNF-α, IL-1β, IL-6, and IL-8, except the lowest dose of Schisandrin A for IL-1β, the rest of the doses tested were able to significantly reduced the concentrations of inflammatory markers. Concentrations of LPS in hepatic and intestinal tissues were significantly increased by E. coli infection, all doses of Schisandrin A significantly reduced the concentration of LPS in hepatic and intestinal tissue. E. coli infection significantly reduced the expression of 2 tight junction proteins (ZO-1 and Claudin-1), the higher doses of Schisandrin A were effective in significantly increasing the expression of these tight junction proteins when compared with the E. coli infected control. Taken together, these results show that Schisandrin A has potential as an alternative therapy for the treatment of colibacillosis in chickens.
In the context of a high proportion of new energy grid connections, demand-side resources have become an inevitable choice for constructing new power systems due to their high flexibility and fast response speed. However, the response capability of demand-side resources is decentralized and fluctuating, which makes it difficult for them to effectively participate in power market trading. Therefore, this paper proposes a robust transaction decision model for demand-side resource aggregators considering multi-objective clustering aggregation optimization. First, a demand-side resource aggregation operation model is designed to aggregate dispersed demand-side resources into a coordinated aggregated response entity through an aggregator. Second, the demand-side resource aggregation evaluation indexes are established from three dimensions of response capacity, response reliability, and response flexibility, and the multi-objective aggregation optimization model of demand-side resources is constructed with the objective function of the larger potential market revenue and the smallest risk of deviation penalty. Finally, robust optimization theory is adopted to cope with the uncertainty of demand-side resource responsiveness, the robust transaction decision model of demand-side resource aggregator is constructed, and a community in Henan Province is selected for simulation analysis to verify the validity and applicability of the proposed model. The findings reveal that the proposed cluster aggregation optimization method reduces the bias penalty risk of the demand-side resource aggregators by about 33.12%, improves the comprehensive optimization objective by about 18.10%, and realizes the optimal aggregation of demand-side resources that takes into account both economy and risk. Moreover, the robust trading decision model can increase the expected net revenue by about 3.1% under the ‘worst’ scenario of fluctuating uncertainties, which enhances the resilience of demand-side resource aggregators to risks and effectively fosters the involvement of demand-side resources in the electricity market dynamics.
The growth and development of naked oat (Avena nuda L.) seedlings, a grain recognized as nutritious and healthy, is limited by drought. Melatonin plays a positive role in plants under drought stress. However, its function is unclear in naked oats. This study demonstrated that melatonin enhances drought stress tolerance in oat seedlings. Melatonin application alleviated the declining growth parameters of two naked oat varieties, Huazao No.2 (H2) and Jizhangyou No.15 (J15), under drought stress by increasing the chlorophyll content and photosynthetic rate of leaves. Melatonin pretreatment induced differential gene expression in H2 and J15 under drought stress. Subsequently, the differential gene expression responses to melatonin in the two varieties were further analyzed. The key drought response transcription factors and the regulatory effect of melatonin on drought-related transcription factors were assessed, focusing on genes encoding proteins in the ABA signal transduction pathway, including PYL, PP2C, ABF, SNRK2, and IAA. Taken together, this study provides new insights into the effect and underlying mechanism of melatonin in alleviating drought stress in naked oat seedlings.
Abstract Background: Although previous studies have found that melatonin can promote seed germination, the phytohormone regulation mechanism by which exogenous melatonin mediates salt tolerance during cotton seed germination is still largely unknown. We investigated the effect of melatonin on the germination traits and physiological parameters of GXM9 cotton seeds ( Gossypium hirsutum L.) under three salt stress treatments (CK, germination of seeds pretreated with water alone; S, germination of seeds pretreated in 150 mM NaCl under salt stress; SM, germination of seeds pretreated in 20 µM melatonin under 150 mM NaCl solution) in the laboratory. Results: We found that salt stress (150 mM) inhibited cotton seed germination and endogenous melatonin accumulation, and pretreatment with 20 µM exogenous melatonin enhanced the cotton germination rate and hypocotyl length as well as the content of endogenous melatonin during seed germination. This suggests that exogenous melatonin promotes seed germination from a morphological perspective. The contents of starch, α-amylase (EC3.3.1.1), β-galactosidase (EC3.2.1.23), abscisic acid (ABA), and gibberellin (GA) were determined simultaneously. The results showed that the α-amylase and β-galactosidase contents in the cotton seeds decreased by 56.97% and 20.18%, respectively, under salt stress compared with the control, while the starch content increased by 11.53% compared with the control at day 7. The ABA content increased by 25.18% and GA content decreased by 27.99% under salt stress compared with the control at 24 h. When exogenous melatonin was applied to the cotton seeds, the content of α-amylase and β-galactosidase increased by 121.77% and 32.76%, respectively, whereas the starch contents decreased by 13.55% compared with the S treatment at day 7. Similarly, the ABA content increased by 12.20% and the GA content increased by 4.77% at 24 h. To elucidate the molecular mechanism by which melatonin promotes seed germination under salt stress, the effects of ABA- and GA-related genes on plant hormone signal transduction were analyzed by quantitative real-time PCR and RNA sequencing. The results indicated that melatonin regulated the expression of ABA and GA genes in the plant signal transduction pathway, induced embryo root development and seed germination, and alleviated dormancy. We found that the expression of the ABA signaling gene GhABF2 was up-regulated and GhDPBF2 was down-regulated, and the expression of GA signaling genes (e.g., GhGID1C and GhGID1B ) was up-regulated by melatonin. Conclusions: We discovered that melatonin enhances salt tolerance in cotton seeds by regulating ABA and GA and by mediating the expression of hormone-related genes in plant hormone signal transduction. This should help us to explore the regulatory mechanisms of cotton resistance and provide a foundation for the cultivation of new varieties.
As the proportion of new energy continues to increase, the safety and stability of the new power system are challenged, urgently requiring the allocation of new flexible resources. This paper proposes a two-stage robust capacity optimization model considering flexibility demand constraints. Firstly, the uncertain characteristics of new energy are described, and a model of flexible resource adjustment capacity is established. Then, uncertain parameters are introduced to construct a robust capacity optimization model considering supply-demand balance, solved by column constraint generation algorithm and KKT theorem. Finally, a power system in a certain region of China is selected as the simulation object for empirical analysis to verify the effectiveness of the constructed model. The results show that the two-stage robust configuration optimization model constructed in this paper can address the uncertainty of power system and the flexibility demand brought by new energy, and the planning results can achieve a balance between the safety and economy of the new power system.
Melatonin application has obvious improving effects on alleviating the drought-induced inhibition of plant growth. However, the root phenotypic dynamics in wheat treated with melatonin remain unknown. This study was conducted using RhizoPot, a novel and improvised in situ root observation device, with three treatments, including normal water condition (CK), drought condition (Ds, relative water content 45–50%), and 100 µM melatonin treatment under drought condition (MT). Results showed that MT application effectively improves root morphological indicators, including root (specific root) length, surface area, and volume; root length density; and the average root diameter of wheat plants. Also, the inhibitory effect of drought on shoot morphology, including plant height, dry weight, net photosynthesis, and stomatal aperture of leaves, were improved significantly through MT under drought condition. Life span and percent survival of fine root, lateral root, and root hair at different segments were also effectively improved under MT treatment. Compared with those shown under CK and Ds, the melatonin contents in leaves and roots were increased, and the expression levels of melatonin-synthesis-related genes (TaCOMT and TaTDC) were upregulated significantly under MT treatment. The findings of this study may clarify the drought resistance mechanism of wheat treated with melatonin under drought stress.
Using insect-resistant transgenic Bt varieties(Bacillus thuringiensis),cotton 33B and Nongdamian 6,applying plowing,rotary tillage,direct drilling as treatments,the physiological characteristics of different positions fruit branch leaves were studied.The experiments were carried out at the teaching and experiment station(Baoding,Hebei Province)of Agricultural University of Hebei,in 2005 and 2006.The result showed:1)The content of chlorophyll and dissoluble protein of different positions fruit branch leaves reduced along a sequence of plowing rotary tillage direct drilling;2)MDA reduced along a sequence of direct drilling rotary tillageplowing.The trends are identical in both varieties.It indicates that plowing is propitious to delay the senescence of fruit branch leaf,the senescence phenomenon of direct drilling is severest,that of rotary tillage is in the middle.Compared with 33B,the content of chlorophyll and dissoluble protein of Nongdamian 6 in middle and late phases was more than that of 33B,the content of MDA was less than that of 33B,which indicated that the capability of antisenescence of Nongdamian 6 was stronger than 33B.
Abstract Background Root system architecture (RSA) exhibits significant genetic variability and is closely associated with drought tolerance. However, the evaluation of drought-tolerant cotton cultivars based on RSA in the field conditions is still underexplored. Results So, this study conducted a comprehensive analysis of drought tolerance based on physiological and morphological traits (i.e., aboveground and RSA, and yield) within a rain-out shelter, with two water treatments: well-watered (75 ± 5% soil relative water content) and drought stress (50 ± 5% soil relative water content). The results showed that principal component analysis identified six principal components, including highlighting the importance of root traits and canopy parameters in influencing drought tolerance. Moreover, the systematic cluster analysis was used to classify 80 cultivars into 5 categories, including drought-tolerant cultivars, relatively drought-tolerant cultivars, intermediate cultivars, relatively drought-sensitive cultivars, and drought-sensitive cultivars. Further validation of the drought tolerance index showed that the yield drought tolerance index and biomass drought tolerance index of the drought-tolerant cultivars were 8.97 and 5.05 times higher than those of the drought-sensitive cultivars, respectively. Conclusions The RSA of drought-tolerant cultivars was characterised by a significant increase in average length-all lateral roots, a significant decrease in average lateral root emergence angle and a moderate root/shoot ratio. In contrast, the drought-sensitive cultivars showed a significant decrease in average length-all lateral roots and a significant increase in both average lateral root emergence angle and root/shoot ratio. It is therefore more comprehensive and accurate to assess field crop drought tolerance by considering root performance.
Leaf senescence reduces the photosynthetic capacity of leaves, thus significantly affecting the growth, development, and yield formation of cotton. Melatonin (MT) is a multipotent substance proven to delay leaf senescence. However, its potential mechanism in delaying leaf senescence induced by abiotic stress remains unclear. This study aimed to explore the effect of MT on delaying drought-induced leaf senescence in cotton seedlings and to clarify its morphological and physiological mechanisms. Drought stress upregulated the leaf senescence marker genes, destroyed the photosystem, and led to excessive accumulation of reactive oxygen species (ROS, e.g., H2O2 and O2-), thus accelerating leaf senescence. However, leaf senescence was significantly delayed when 100 μM MT was sprayed on the leaves of the cotton seedlings. The delay was embodied by the increased chlorophyll content, photosynthetic capacity, and antioxidant enzyme activities, as well as decreased H2O2, O2-, and abscisic acid (ABA) contents by 34.44%, 37.68%, and 29.32%, respectively. MT significantly down-regulated chlorophyll degradation-related genes and senescence marker genes (GhNAC12 and GhWRKY27/71). In addition, MT reduced the chloroplast damage caused by drought-induced leaf senescence and maintained the integrity of the chloroplast lamellae structure under drought stress. The findings of this study collectively suggest that MT can effectively enhance the antioxidant enzyme system, improve photosynthetic efficiency, reduce chlorophyll degradation and ROS accumulation, and inhibit ABA synthesis, thereby delaying drought-induced leaf senescence in cotton.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)