Chlorophyll Content Research Articles

Comparison of chlorophyll content estimation using chlorophyll meters and leaf chloroplast pigments extracted from Eucalyptus urophylla and Khaya senegalensis seedlings

Context Estimating chloroplast pigment content by using chlorophyll meters is faster and cheaper than by using traditional pigment-extraction protocols. However, the reliability of chlorophyll meters requires a preliminary test of the relationship between the estimated and actual concentrations. Aims To establish an optimized protocol for extracting leaf chloroplast pigments from Eucalyptus urophylla and Khaya senegalensis seedlings. Moreover, we evaluated the relationship between chlorophyll-content estimation by using chlorophyll meters with the SPAD index by using SPAD-502 and with Falker chlorophyll index (FCI) by using ClorofiLOG, and that by using the optimal chloroplast pigment-extraction protocol. Methods The effectiveness of dimethylsulfoxide (DMSO) saturated with CaCO3 at 25°C and 65°C and 80% acetone (v/v) was assessed as extractors, by using different incubation times. Chlorophyll-content estimation was assessed using chlorophyll meters with the SPAD index by using SPAD-502 and with Falker chlorophyll index (FCI) by using ClorofiLOG. Key results For both Eucalyptus urophylla and Khaya senegalensis seedlings, the optimal protocol for extracting pigments from chloroplasts was incubation for 4 h by using DMSO saturated with CaCO3 at 65°C. Chlorophyll-content estimation using SPAD-502 and ClorofiLOG showed a strong positive correlation with measurements from the optimized pigment-extraction protocol. Furthermore, the regression equations of the chlorophyll-content estimation with chlorophyll meters allowed predicting the real content, because the values were very close to those measured using traditional extraction protocols. Conclusions The SPAD index and the FCI were reliable methods for estimating chlorophyll content in seedlings of both species. This could make measuring the chloroplast pigments faster and cheaper, especially regarding experimentation under field conditions.

Biomass Allocation in Gentianella turkestanorum is Driven by Environmental Factors and Functional Traits

Exploring the elevation distribution characteristics, biomass allocation strategies, and the effects of elevation, soil factors, and functional traits on the biomass of Gentianella turkestanorum (Gand.) Holub is of great significance for the production, development, utilization, and protection of the medicinal material resources. In this study, we investigated the biomass and functional traits of the root, stem, leaf, and flower of G. turkestanorum, analyzing their elevation distribution patterns, allometric growth trajectories, and their correlations. The results showed that the biomass of different organs of G. turkestanorum decreases with increasing elevation, and the belowground biomass/aboveground biomass increases with elevation. The flower biomass accounts for 59.24% of the total biomass, which was significantly higher than that of other organs. G. turkestanorum biomass follows the optimal allocation theory, adopting a ‘pioneering’ growth strategy at low elevations and a ‘conservative’ strategy at high elevations. Chlorophyll content and leaf thickness of G. turkestanorum were positively correlated with elevation, but leaf dry matter content and the number of flowers were negatively correlated with elevation. Compared to functional traits, elevation and soil factors have a stronger explanatory power regarding the biomass of G. turkestanorum. Elevation, soil moisture content, pH, available phosphorus, total nitrogen, and ammonium nitrogen significantly affect the biomass of G. turkestanorum, with only pH showing a positive correlation with biomass. Among these factors, elevation, soil moisture content, and pH significantly impact the accurate prediction of G. turkestanorum biomass. The number of flowers, crown width, root length, root diameter, and leaf dry matter content all have a significantly positive correlation with the biomass of G. turkestanorum, with the number of flowers and root diameter making significant contributions to the accurate prediction of biomass. Elevation can directly affect the biomass of G. turkestanorum and can also indirectly affect it through other pathways, with the direct effect being greater than the indirect effect.

Impact of two arbuscular mycorrhizal fungi species on arsenic tolerance and accumulation in safflower (Carthamus tinctorius L.)

BackgroundArbuscular mycorrhizal fungi (AMF) can regulate metal(loid) tolerance in plants and their capacity for phytoremediation. These effects can vary depending on the host plant and the AMF species. The impact of different AMF species on the ability of safflower (Carthamus tinctorius L.) for arsenic (As) phytoremediation is still largely unknown. Therefore, this study aimed to assess the effect of two AMF species, Rhizophagus irregularis, and Funneliformis mosseae, on the tolerance and accumulation of As in safflower in soils spiked with varying arsenate concentrations (0, 25, 50, and 100 mg kg−1).ResultsThe results indicated that both AMF species established effective symbiotic relationships with safflower. However, plants inoculated with R. irregularis exhibited higher mycorrhizal dependency and root colonization, especially under 100 mg kg−1 As. Both AMF species significantly improved plant growth parameters, chlorophyll content, and phosphorus (P) nutrition, which resulted in increased P/As ratio and enhanced tolerance index in safflower plants. In addition, AMF inoculation reduced As-induced lipid peroxidation by enhancing catalase and peroxidase activity in leaves and roots. While the mycorrhizal symbiosis didn’t affect As availability in soils, it significantly reduced shoot As concentration and the translocation factor under all As levels. Furthermore, mycorrhizal inoculation, especially with R. irregularis, increased As concentration and modified-bioconcentration factor in the roots and enhanced total As uptake per plant.ConclusionsBased on the results and multivariate analyses, both AMF species, particularly R. irregularis, enhanced safflower's As tolerance by retaining As in roots, improving phosphorus nutrition, and increasing antioxidant enzyme activity, showcasing their potential to enhance phytostabilization in safflower plants.

A Seed Endophytic Bacterium Cronobacter dublinensis BC-14 Enhances the Growth and Drought Tolerance of Echinochloa crus-galli

Successful seed germination and plant seedling growth often require association with endophytic bacteria. Barnyard grass (Echinochloa crus-galli (L.) P. Beauv.) is a main weed during rice cultivation and has frequently been found in drought-prone fields such as cornfields in recent years. To determine whether endophytic bacteria enhance the survival chances of barnyard grass in dryland conditions, endophytic bacteria were collected from barnyard grass seeds. An endophytic bacterial strain, BC-14, was selected and confirmed as Cronobacter dublinensis based on its morphology, physiology, biochemistry, and genomic information. Moreover, C. dublinensis BC-14 secreted IAA in the Luria–Bertani broth up to 28.44 mg/L after 5 days; it could colonize the roots of barnyard grass. After the inoculation with seeds or the well-mixed planting soil, the bacterium can significantly increase the root length and plant height of barnyard grass under drought conditions. When comparing with the control group on the 28th day, it can be seen that the bacterium can significantly increase the contents of chlorophyll b (up to 7.58 times) and proline (37.21%); improve the activities of superoxide dismutase, catalase, and peroxidase (36.90%, 51.51%, and 12.09%, respectively); and reduce the content of malondialdehyde around 25.92%, which are correlated to the drought tolerance. The bacterial genomic annotation revealed that it contains growth-promoting and drought-resistant functional genes. In a word, C. dublinensis BC-14 can help barnyard grass suppress drought stress, promote plant growth, and enhance biomass accumulation, which is helpful to interpret the mechanism of weed adaptability in dry environments.

Characterization of Lipid Production in Chlorella sp. Cultivated in Different Plant Fertilizers

Microalgae have gained attention due to their higher reproduction rate and lipid productivity. In particular, various stress conditions lead to an overproduction of lipids in microalgae cells. The study investigated the influence of additional CO2 introduced with air into the reactor during biomass growth of Chlorella sp. Additionally, increased phosphorus concentration in the medium under stress cultivation (low nitrogen concentration) was examined. The partial pressure of CO2 and its increased availability to Chlorella sp. in the cultivation medium increased biomass growth (1.4 times) and chlorophyll content (2.5 times) in microalgae cells. A high phosphorus fertilizer significantly increased lipid production under stress conditions with CO2 supply to 85.2 mg/g (2.6 times) and without CO2 to 73.8 mg/g (2.2 times). A high concentration of phosphorus in the culture medium stimulated the synthesis of C16:0 (about 38–45%) and C18:1 CIS9 (about 24–30%). The results confirm that the fertilizers can be used as a culture medium to induce stress and stimulate lipid production. Adjusting the composition of the fertilizers and controlling the additional CO2 supply could prove beneficial to increase the content of the desired fatty acids.

Enhancing salicylic acid levels by its exogenous pretreatment to mitigate Fusarium oxysporum-induced biotic stress in Vigna mungo: defense pathways insights.

Fusarium oxysporum disrupts redox homeostasis in Vigna mungo, likely by interfering with salicylic acid signaling, which can be ameliorated by boosting PAL and its related pathways via salicylic acid pretreatment. Fusarium oxysporum, a widespread soil-borne fungus, significantly threatens global crops. This study centers on elucidating the infection strategies employed by F. oxysporum against a new and underexplored host Vigna mungo, a leguminous crop of high agronomic value, and the defense mechanisms that can be activated against the infection, aiming to uncover how these responses can be leveraged to develop potential countermeasures. Building on prior work demonstrating the in vitro antifungal efficacy of phytohormones, including salicylic acid (SA), this study further investigates SA pretreatment at 100µM, which previously reduced reactive oxygen species (ROS) and improved germination under Fusarium stress. Through a comprehensive analysis of V. mungo plants pretreated with SA and subjected to F. oxysporum infection, we observed that fungal exposure reduced growth, chlorophyll content, and levels of proteins, phenolics and flavonoids, while increasing stress markers and antioxidant activity. SA pretreatment mitigated these effects by boosting antioxidant molecules and activating the phenylalanine ammonia-lyase (PAL) pathway, thereby enhancing endogenous SA and ROS scavenging. Furthermore, qRT-PCR analysis confirmed SA-mediated upregulation of antioxidant (catalase and peroxidase), fungal stress response genes ((pathogenesis-related gene 4 (PR4) and defensin (DEF)) and SA synthesis and regulator genes (PAL and WRKY70) involved in plant systemic resistance, while LC-MS data revealed an altered metabolic profile with increased phytoalexins and antioxidants synthesis. Overall, SA pretreatment confers resistance against F. oxysporum in V. mungo by modulating endogenous SA and metabolic profile to activate key defense pathways and redox homeostasis, highlighting its potential in plant defense strategies and reinforcing our proposed model of SA action.

Assessing the Water Quality and Its Influence on the Chlorophyll-a Concentration in the Karnaphuli River Estuary

The Karnaphuli river, essential for the economy and biodiversity of Bangladesh, faces increasing threat due to the proximity of industries, necessitating regular water quality monitoring to safeguard both environmental and economic interests. Hence, this study investigates the nutrient distribution and physicochemical parameters (pH, temperature, turbidity, dissolved oxygen, and electric conductivity) in relation to the chlorophyll a dynamics in the Karnaphuli river estuary during the monsoon season for evaluating water quality in the river estuary, stretching about 42 kilometres. Surface and deep-water samples have been collected from five different stations. Nutrients, chlorophyll concentration, and dissolved oxygen have been evaluated using a Continuous Flow Autoanalyzer, spectrophotometer, and DO kit, respectively, while electric conductivity, temperature, turbidity, and pH have been measured using a CTD tool. Spatial mapping and correlation analysis have been conducted as well. Temperature and pH values didn’t show much fluctuation within the sampling stations falling within the range of 29°C-31°C and 6.5-7.5, respectively. Positive correlation of pH with ammonia at surface water (r=92) indicates that the effluents of ammonia plants are the primary source of pH in river water. TSP plant effluent has been shown to cause turbidity, evident from the positive correlation between phosphate and turbidity both at surface and deep water (r=91). Increase in turbidity (562.1 NTU) resulted in a decrease in dissolved oxygen (3 mg/L), which poses a serious threat to the survival of aquatic life, including fish, in the river downstream. Decreased water quality at river downstream is evident by comparatively low chlorophyll presence of 1.5 μg/L. However, the shallow coastal region in the study area is indicative of a healthy aquatic ecosystem evident by the presence of high productivity indicated by high chlorophyll concentration of 8.9 μg/L, which is due to comparatively low levels of turbidity and also the water condition there met the standard DO for fisheries (>5mg/L). The findings underscore the critical importance of regular water quality monitoring in the Karnaphuli river to safeguard both the environment and economy of Bangladesh, urging collective action to mitigate the escalating threats posed by industrial activities and ensure the long-term sustainability of the river ecosystem. The Dhaka University Journal of Earth and Environmental Sciences, Vol. 13(1), 2024, P 91-104

Spatiotemporal Assessment of Water Quality and Quantity of the Kaptai Lake at Rangamati, Bangladesh - An Approach of Remote Sensing, Field Investigation and Laboratory Analysis

Monitoring water quality and quantity is essential for sustainable water resource management. This study investigates changes in the extent and water quality of Kaptai Lake using remote sensing, field measurements, and laboratory analysis. Analysis of Landsat TM/OLI images from 1989, 2000, 2010, and 2021 shows that the lake's water extent ranges from 380 km² (in 2010) to 435 km² (in 2021), with an average of 407.5 km². The extent of water decreased by approximately 3% from 1989 to 2010 and increased by about 5% from 2010 to 2021 due to changing rainfall patterns, dam operations, sedimentation, and land use changes. Seasonal variations in chlorophyll-a concentration and turbidity, analyzed using Sentinel 2B images from 2022 and 2023, indicate mesotrophic to eutrophic conditions and higher turbidity in post-monsoon. The study found that nutrient enrichment from untreated sewage, agricultural runoff, and algal growth affect chlorophyll-a levels, while development activities, excessive rainfall, and sedimentation influence turbidity. Linear regression analyses show strong positive correlation between field obtained and image derived values both for chlorophyll-a (R2 0.621) and turbidity (R2 0.698). Physico-chemical parameters such as pH, EC and temperature have been measured in the field and hydrochemical parameters including, cations and anions have been measured by laboratory analysis to assess the contemporary water quality status. The average values for pH, EC and temperature are 7.55, 119.85 µS/cm and 22.17 °C respectively. The cationic dominance in the studied segment of the Lake is in the order of Ca2+ > Na2+ > Mg2+>K+ > Fe2+ >Mn2+. On the other hand, the anions are in the order of HCO3- > SO42- > Cl- > NO3-. All the physico-chemical parameters of the lake water fall within the Bangladesh Drinking Water Limit (BDWL) and are not linked to chlorophyll-a and turbidity variations. The findings of this study can help mitigate the deterioration of Kaptai Lake by addressing water quality and extent issues, promoting effective and sustainable lake management strategies. The Dhaka University Journal of Earth and Environmental Sciences, Vol. 13(1), 2024, P 121-139

Impact of Carbon Dioxide Levels on Biochemical Parameters Associated with Stem Rot Disease in Groundnut

Background: Sclerotium rolfsii is a widespread soil-borne fungal pathogen recognized for causing disease in a wide variety of agricultural and horticultural crops globally. Despite the economic losses attributed to this pathogen, there are limited reports concerning the biochemical alterations in groundnut in response to increased carbon dioxide levels and pathogen interactions. Methods: A pot culture experiment was carried out at ICRISAT during the rabi season 2022-23 in Open Top Chambers (OTC) to assess the biochemical responses of groundnut to climate change and pathogen interactions. The study was carried out at three different carbon dioxide levels (400 ppm, 550 ppm and 700 ppm) using the susceptible groundnut cultivar TMV 2 and the moderately resistant cultivar ICGV-14082. Result: The levels of total phenols, oxalic acid, ascorbic acid, catalase, peroxidases, polyphenol oxidase, and chlorophyll content index were elevated in groundnut plants infected with stem rot due to increased carbon dioxide levels. The biochemical activity was high at its peak in inoculated plants on 4th and 6th day post-inoculation of the pathogen and gradually declined on 8th and 10th days.

Enhancing Soil Health and Tea Plant Quality Through Integrated Organic and Chemical Fertilization Strategies

As the global demand for high-quality tea increases, adopting sustainable agricultural practices is crucial to maintaining environmental health and improving crop productivity. Employing organic fertilizers has the potential to boost agricultural output and improve soil health, as well as curb the spread of pests and diseases. The purpose of this survey was to determine the impact of a range of organic fertilizer mixtures on both tea plants and rhizosphere soil characteristics in tea plantations. This study investigated the response of Jin Guanyin tea (Camellia sinensis L.) plants to various organic fertilizer ratios: 2/3 chemical fertilizer + 1/3 organic fertilizer (JTC), 1/2 chemical fertilizer + 1/2 organic fertilizer (JHOC), 1/3 chemical fertilizer + 2/3 organic fertilizer (JTO), and organic fertilizer only (JOF), with chemical fertilizer alone (JCF) as the control. The experiment was conducted in Xingcun Town, Wuyishan, Fujian Province, China, on 13 October 2021. Key metrics measured included tea plant growth indicators, soil physicochemical properties, enzyme activities, and microbial functional diversity. Results show that JTC and JTO produce the largest leaf area and bud weight, significantly surpassing those in JCF. JCF demonstrated the longest new tip length and highest bud density, while JHOC achieved the highest chlorophyll content, significantly exceeding JCF. Soil analysis revealed that total nitrogen, available nitrogen, organic matter, and pH were highest in JOF, significantly overtaking JCF. Conversely, total phosphorus, available potassium, and available phosphorus levels were highest in JCF. JHOC also had the highest total potassium content compared to JCF. Soil enzyme activity assessments showed that polyphenol oxidase and urease activities peaked in JTC, significantly exceeding those in JCF. JHOC exhibited the highest acid phosphatase activity, while JTO exhibited the highest protease activity. Catalase activity was highest in JOF, both significantly surpassing JCF. Microbial functional diversity analysis indicated that combined organic fertilization improved soil microorganisms’ utilization of carbon sources, significantly enhancing the Shannon diversity index and evenness. Key carbon sources identified included α-cyclodextrin, D-galacturonic acid, and 4-hydroxy benzoic acid. Overall, JHOC emerged as the optimal fertilization strategy, yielding superior growth indicators, enhanced soil physicochemical properties, increased enzyme activity, and improved microbial functional diversity compared to JCF. This study has important value for guiding the rational application of fertilizers in tea gardens, improving the soil environment of tea gardens, enhancing the quality of tea leaves, and achieving sustainable tea production.

Non-Destructive Detection and Visualization of Chlorophyll Content in Cherry Tomatoes Based on Hyperspectral Technology and Machine Learning

The cherry tomato has an important economic value and an increasingly broad market, and the chlorophyll content of cherry tomato leaves can directly reflect the plant’s photosynthetic ability, thus indirectly reflecting its growth status. Therefore, this paper proposes a regression detection method for chlorophyll in cherry tomato leaves by combining machine learning and hyperspectral technology to realize non-destructive, fast, and more accurate detection. Firstly, Moving-Average (MA) preprocessing was chosen as the pretreatment method for this paper, and three regression models of principal component regression (PCR), random forest (RF), and partial least squares regression (PLSR) were established with leaf chlorophyll under different nitrogen concentrations. The CARS_PLSR algorithm has the highest prediction accuracy with accuracy, precision, RMSEC, and RMSEP of 0.8790, 0.9187, 2.9581, and 2.5578, respectively. The study examined the impact of various nitrogen concentrations on the chlorophyll content of cherry tomato leaves, and it was found that the high concentration of nitrogen inhibited the SPAD value of cherry tomato leaves more than that of the low concentration, and the optimal concentration of nitrogen fertilization for tomatoes was 300 mg·L−1. Finally, a regression model was established by using CARS-PLSR combined with the pseudo-color map technology, and a distribution map of chlorophyll content in different SPAD value gradients of cherry tomato leaves was obtained, which could visualize the distribution of chlorophyll and its distribution sites in the leaves and understand the growth status of cherry tomatoes. The distribution of chlorophyll content in different SPAD values of cherry tomato leaves was obtained by using the CARS-PLSR regression model combined with pseudo-color map technology, which can visualize the distribution of chlorophyll in the leaves and the parts of distribution and understand the growth condition of cherry tomatoes. Finally, the optimal model is applied in conjunction with a sprayer to automate fertilizer application.

Chlorophyll in water and bottom sediments as an indicator of the trophic state of Busse Lagoon (Sakhalin Island)

New associated data on the content of chlorophyll a and its derivatives in the water and bottom sediments of Busse Lagoon (Sakhalin Island) have been obtained. Chlorophyll a and chlorophyll degradation products (Chl a + Ph) in the water column is represented predominantly by the active form (61.4 ± 1.1%), in bottom sediments – by a product of its degradation (84.7 ± 2.5%). The connection between pigments in water and bottom sediments, as well as the abiotic conditions of primary production, has been revealed. For the first time, for a unique reservoir characterized by overgrowth of aquatic vegetation, silt accumulation and regular death of aquatic organisms, the similarity of the average annual sedimentation rate in the lagoon with the ratio of pelagic and benthic pigments was shown. The prevailing importance of the biotic factor in the formation of trophic conditions has been established. Based on the average content of Chl a + Ph in water (4.1 ± 0.8 mg/dm3) and in bottom sediments (13.5 ± 4.0 μg/g d.s.), Busse Lagoon is a mesotrophic reservoir. Trophic state of benthic in the period 2013–2021 is preserved, remaining oligotrophic in the shallow coastal zone and mesotrophic in the central part of the lagoon.

Zinc and Phosphate Solubilizing by Rhizobacteria Promotes Lettuce (Lactuca sativa L.) Growth in Salty Conditions

Due to climate change, the world is negatively affected by drought, temperature, salinity, and flood stress, leading to a significant decline in crop production. Lettuce is particularly significant when considering salt stress. To increase plant tolerance to salinity, various strategies are employed to support the development of agriculture. Rhizobacteria play a key role in regulating phosphorus (P) and zinc (Zn) homeostasis in plants. According to the study results, Rhizobium bacteria supported plant growth by improving the solubility of zinc and phosphate. These findings highlight the beneficial effects of plant growth-promoting rhizobacteria (PGPR) on the antioxidant system, which helps detoxify reactive oxygen species. The relationship between proline accumulation and antioxidant enzyme activities showed that PGPR inoculation enhanced the plant's defense mechanism against salt stress. In establishing this tolerance, increases in chlorophyll content, repair of membrane repair, and higher leaf relative humidity under salt stress were observed. PGPR also improved seedling height, diameter, and fresh and dry weight under stress by 70%, 51.4%, 55%, and 109%, respectively, due to the stress-mitigating effects of P and Zn. In conclusion, it is predicted that there will be a need to develop fertilization programs containing different rhizobacteria and Zn+P combinations. These programs would activate the antioxidant mechanism in saline soils, stabilize physiological processes, and positively impact plant growth.

Role of bio health extract on wheat growth according to Zadoks decimal scale

Combating climate change and promoting sustainability are agricultural experts' priorities in Iraq. Using environmentally friendly fertilizers on strategic crops is considered a milestone for accomplishing that. This study aimed to determine the effect of Bio Health fertilizer spraying on some growth qualities of two wheat cultivars (Triticum aestivum L.). A field experiment was conducted at the Agricultural Research Station, Faculty of Agricultural Engineering Sciences - University of Baghdad, during the winter season 2023-24. A randomized complete block design (RCBD) was used in a split-plot arrangement with three replicates, and the experiment included two factors, the first in the main plots such as two wheat cultivars (Ibaa 99 and Adina), while the second factor in the secondary plots was spraying with Bio Health at concentrations of 800, 1600 and 2400 mg/L, in addition to the control treatment (without spraying). The results showed the superiority of the Ibaa 99 cultivar in plant height, the area of the flag leaf, the number of total branches, chlorophyll content, dry weight of the flag leaf, dry weight of the plant, crop growth rate and biological quotient with an increase of 3.64, 15.77, 5.01, 3.38, 7.33, 3.31, 3.34 and 5.73%, respectively. The results also showed the superiority of spraying with Bio Health at a concentration of 1600 mg/L compared to the comparative treatment, the number of total branches, the dry weight of the plant, the growth rate of the crop and the biological yield, with an increase of 28.39, 48.88, 13.21, 12.10 and 23.19%. As for the study's two factors overlap, the results demonstrated a considerable superiority between the two qualities, the height of the plant as well as its dry weight, and the combination of Bio Health spraying at a concentration of 1600 mg/L for the Ibaa 99 cultivar achieved the highest averages.

Mitigation of Flood Stress in Mazamort Pepper Variety through Manganese Application

This study was conducted to investigate the effect of Mn application on the resistance of pepper plants exposed to flood stress. The study was conducted in a climate-controlled room at Siirt University, utilizing the Mazamort three-lobed pepper variety as plant material. In the climate chamber (19 m²), conditions were established at 24±1°C during the day and 18±1°C at night, with a light/dark photoperiod of 16/8 hours. The growing medium consisted of a 2:1 (v) mixture of peat and perlite. Four treatment groups were established: control, flood stress, 2.5 mg/L manganese (Mn), and flood stress combined with 2.5 mg/L Mn. Sixty-day-old Mazamort pepper plants were subjected to continuous flooding and manganese application at each watering. The duration of flood stress was set at 0 days (control) and 10 days. The experiment was designed using a randomized complete block design with three replications, each containing 10 plants. Parameters evaluated at the end of the study included visual assessment, plant height, stem diameter, leaf number, leaf fresh and dry weight, leaf moisture content, root fresh and dry weight, root moisture content, chlorophyll content (SPAD value), ion leakage, relative water content (RWC), and turgor loss. The highest plant height was observed in the 2.5 mg/L manganese treatment (45.82 cm), while the greatest stem diameter was recorded in the control group. The highest leaf number (30.60) and SPAD value (35.34) were also noted in the control group. RWC was highest at 96.90% in the 2.5 mg/L manganese treatment. The maximum turgor loss was 5.606% in the control group, and the highest ion leakage (17.880%) was observed in the 2.5 mg/L manganese treatment. It was concluded that manganese application mitigated the negative effects of flood stress on various parameters; however, it did not fully restore the values to control group levels.

Impact of Salicylic Acid and Potassium Silicate in Ameliorating the Drought Stress Effect on Sorghum (Sorghum bicolor L. Moench)

Aims: The present study highlights the impact of salicylic acid and potassium silicate in reducing the deleterious effect of drought stress on sorghum. Study Design: Split plot design. Place and Duration of Study: Agricultural College Farm, Bapatla, Andhra Pradesh during rabi, 2023-24. Methodology: The experiment consist of two main treatments i.e., water stress treatments viz., M1 (stress treatment i.e., moisture stress was imposed from vegetative to flowering (25-70 DAS) and M2 (No stress treatment) and eight sub treatments viz., No spray (S1), K-Silicate @50ppm at 35+45 DAS (S2), K-Silicate @100ppm at 35+45 DAS (S3), SA @150ppm at 35+45 DAS (S4), SA @200ppm at 35+45 DAS (S5), K-Silicate @50ppm + SA @200ppm at 35+45 DAS (S6), K-Silicate @100ppm + SA @200ppm at 35+45 DAS (S7) and K-Silicate @150ppm + SA @200ppm at 35+45 DAS (S8) replicated thrice. The plant samples were collected on 30, 50 and 70 DAS. Results: The sorghum plants under water stress showed drastic reductions in chlorophyll content (54.9%), relative water content (34.1%) and increase in membrane injury index (1.9 folds), proline content (1.8 folds) and catalase activity (3.6 folds). The combined spray of potassium silicate @100ppm + SA @200ppm exhibited superior performance by enhancing the chlorophyll content by 59.1%, relative water content by 32.5, proline content by 26.1%, catalase activity by 30.4% and reducing membrane injury index by 28.9%. Conclusion: It can be concluded that the foliar application of @100ppm + SA @200ppm at 35 + 45 DAS helped the sorghum plants from the negative effects of water stress from vegetative to flowering stages.

Antioxidant and Ultrastructural Alterations in Wheat During Drought-Induced Leaf Senescence

Wheat is one of the most important crops to ensure food production globally. Understanding the mechanism of leaf senescence in wheat plays a crucial role in improving its productivity and resilience under various stress scenarios. In this study, we investigated biochemical, functional, and ultrastructural changes during leaf senescence in wheat genotypes with contrasting drought tolerance. For this, key parameters such as chlorophyll and total protein content, membrane stability, malondialdehyde level, and the activity of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, benzidine peroxidase, and catalase) were comparatively analyzed during both natural and drought-induced senescence. Additionally, the expression of superoxide dismutase isoform genes functioning in different cellular compartments was studied, alongside ultrastructural changes in flag leaves. The experiments involved genotypes of bread wheat (Triticum aestivum L.) and durum (Triticum durum Desf.) wheat. The plants were grown in controlled environment chambers under control and drought conditions using a completely randomized design. After the booting stage, irrigation was discontinued for drought-treated plants. Flag leaves were sampled at 7, 14, 21, 28, and 35 days after anthesis. Drought-tolerant genotypes exhibited slower chlorophyll degradation, lower lipid peroxidation, enhanced membrane stability, and stronger antioxidant responses, allowing them to maintain cellular function longer, whereas sensitive genotypes showed accelerated leaf senescence. Transcript levels of FeSOD increased significantly post-flowering but declined as senescence progressed, while MnSOD expression exhibited a rise towards the later stages of ontogenesis across all studied genotypes. Ultrastructural analysis revealed progressive damage to chloroplast membranes, thylakoid structures, and mesophyll cell walls under stress conditions, particularly in sensitive genotypes. These findings contribute to a deeper understanding of the physiological and molecular responses of wheat to drought stress, offering potential targets for improving crop performance in water-limited environments.

Overexpression of rice High-affinity Potassium Transporter gene OsHKT1;5 improves salinity and drought tolerance in Arabidopsis.

Rice is subjected to various environmental stresses, resulting in significant production losses. Abiotic stresses, particularly drought and salinity, are the leading causes of plant damage worldwide. The High-affinity Potassium Transporter (HKT) gene family plays an important role in enhancing crop stress tolerance by regulating physiological and enzymatic functions. This study investigates the effect of overexpressing the rice HKT1;5 gene in Arabidopsis thaliana on its tolerance to salinity and drought. The OsHKT1;5 gene was introduced into Arabidopsis under the control of 35S promoter of CaMV via floral dip transformation method. PCR confirmed the integration of the transgene into the Arabidopsis genome, while qPCR analysis showed its expression. Three transgenic lines of OsHKT1;5 were used for stress treatment and phenotypic studies. The overexpressed lines showed considerably higher germination rates, increased leaf counts, greater fresh and dry weights of the roots and shoots, higher chlorophyll contents, longer root lengths, and reduced Na+ levels together with increased K+ ions levels after salt and drought treatments, in comparison to wild-type plants. Furthermore, overexpressed lines exhibited higher antioxidant levels than wild-type plants under salinity and drought conditions. In addition, transgenic lines showed higher expression levels of the OsHKT1;5 gene in both roots and shoots compared to wild-type plants. In conclusion, this study revealed OsHKT1;5 as a promising candidate for enhancing tolerance to salinity and drought stresses in rice, marking a significant step toward developing a new rice variety with improved abiotic stress tolerance.

Evaluation of Vegetative Characteristics of White Wine Grape Varieties for Growth and Yield Parameters in Semi-arid Conditions of India

The present study was conducted at ICAR- National Research Centre for Grapes, Pune during fruiting season of 2022-2023 and 2023-24. The variety Sauvignon Blanc stood out among white wine varieties, showing superior growth parameters like pruned biomass (0.853 Kg/vine), shoot length (102.56 cm), internodal length (7.89 cm), number of leaves (25.61/fruiting shoot) and yield parameter like number of bunches (60.50/vine). Minimum days taken to bud sprout (8.50 days) and higher shoot diameter (7.94 mm) was recorded in Charak-2. Higher leaf area was recorded in Riesling (3532.27 cm2/fruiting shoot) and Muscat Petit (150.21 cm2/leaf) varieties. Higher chlorophyll content was recorded in White Muscat (22.28 mg/ml). Higher number of berries (157.56/bunch) recorded in Trebbiano. Yield-related metrics like bunch weight (183.20 g) higher in Muscat Petit, 100 berry weight (186.80 g) in Riesling, yield in Marsanne (8.53 kg/vine and 10.32 MT/acre) for pooled mean basis.

Comparative Study of Water and Fertilizer Regimes on Water Potential, Phenolic Substances, and Photosynthetic Characteristics of Pistacia weinmannifolia

Effective water and fertilizer management is crucial for the forestry production of Pistacia weinmannifolia. This experiment employed an orthogonal design to measure the water potential, anthocyanins, chlorophyll, and photosynthetic parameters of Pistacia weinmannifolia under different water and fertilizer regimes. The effects of different water and fertilizer regimes on the water potential, phenolic compounds, and photosynthetic characteristics of Pistacia weinmannifolia were analyzed. A comprehensive analysis method was used to evaluate and establish the best water and fertilizer regimes system. The results showed that the water and fertilizer regimes increased the water potential, anthocyanins, chlorophyll content, flavonoids, and photosynthesis (p < 0.05). During the mid-growth stage and late mid-stage growth of Pistacia weinmannifolia, the fertilizers with the most significant effects on water potential, chlorophyll, and anthocyanins were nitrogen (N) and phosphorus (P). The supply of a certain amount of N and P had positive effect on water potential, chlorophyll, and anthocyanins. Increasing N content was more effective in improving carboxylation efficiency than increasing P content. The effect of N content on photosynthetic efficiency was greater than that of P content Analyses using the TOPSIS model demonstrate that Pistacia weinmannifolia exhibits superior comprehensive efficiency in water potential, chlorophyll, flavonoid, and anthocyanin content. When applying 0.54 g·plant−1 of pure P and 0.67 g·plant−1 of pure N, with the relative soil moisture content maintained at 85%, the optimal comprehensive benefit for photosynthetic indicators is achieved with 0.34 g·plant−1 of pure P and 0.77 g·plant−1 of pure N, while maintaining the relative soil moisture content at 46.66%. These findings indicate that the water–fertilizer coupling treatment group exhibited improved growth status and photosynthesis. Therefore, the cultivation of Pistacia weinmannifolia should prioritize maintaining a balanced water–fertilizer ratio to optimize resource utilization.