Dry Biomass Research Articles

Morpho-physiological studies of sandalwood-host interaction under individual and interactive water and salt stress.

To find out the possibilities of growing white sandalwood in sub-tropical regions of India where farmers facing the problem of water deficit and salinity stress, a RBD experiment was conducted. Sandalwood grown alone and with five selected hosts (Alternanthera sp., Neem, Shisham, Dek and Agarwood) on the basis of prior study under water deficit, salinity stress and combined water deficit and salinity stress. Sandalwood plants were harvested after 180days of imposing stress treatments. Morphological traits (plant height, collar diameter, shoot fresh and dry biomass) showed significant reduction under water deficit and salinity stress, which were further aggravated under combined water deficit and salinity stress. Studied plant water traits, ionic balance and gas exchange attributes were also reduced by these stresses. While among studied host, Shisham and Dek identified as the best host species under water deficit, salinity and interactive stress by maintaining ion homeostasis, osmotic adjustments and plant water regulation. Results depicted that sandalwood plants cultivated alone were not able to survive under salinity and combined stress conditions and showed poor growth under water deficit and control conditions. Different indices were also calculated based on morpho-physiological and ionic traits and also indicated that sandalwood grown with Dalbergia sissoo and Melia dubia showed higher drought, salt and stress tolerance potential, which made sandalwood adaptable under these stresses. Therefore, the present study signifies the importance of host especially D. sissoo and M. dubia which might be excellent long-term host species for sandalwood cultivation under sub-tropical conditions to thrive under changing environments.

Effects of Lactone- and Ketone-Brassinosteroids of the 28-Homobrassinolide Series on Barley Plants under Water Deficit

The aim of this work was to study the ability of 28-homobrassinolide (HBL) and 28-homocastasterone (HCS) to increase the resistance of barley (Hordeum vulgare L.) plants to drought and to alter their endogenous brassinosteroid status. Germinated barley seeds were treated with 0.1 nM HBL or HCS solutions for two hours. A water deficit was created by stopping the watering of 7-day-old plants for the next two weeks. Plants responded to drought through growth inhibition, impaired water status, increased lipid peroxidation, differential effects on antioxidant enzymes, intense proline accumulation, altered expression of genes involved in metabolism, and decreased endogenous contents of hormones (28-homobrassinolide, B-ketones, and B-lactones). Pretreatment of plants with HBL reduced the inhibitory effect of drought on fresh and dry biomass accumulation and relative water content, whereas HCS partially reversed the negative effect of drought on fresh biomass accumulation, reduced the intensity of lipid peroxidation, and increased the osmotic potential. Compared with drought stress alone, pretreatment of plants with HCS or HBL followed by drought increased superoxide dismutase activity sevenfold or threefold and catalase activity (by 36%). The short-term action of HBL and HCS in subsequent drought conditions partially restored the endogenous B-ketone and B-lactone contents. Thus, the steroidal phytohormones HBL and HCS increased barley plant resistance to subsequent drought, showing some specificity of action.

Inorganic salt starvation improves the polysaccharide production and CO2 fixation by Porphyridium purpureum.

The microalgae industry shows a promising future in the production of high-value products such as pigments, phycoerythrin, polyunsaturated fatty acids, and polysaccharides. It was found that polysaccharides have high biomedical value (such as antiviral, antibacterial, antitumor, antioxidative) and industrial application prospects (such as antioxidants). This study aimed to improve the polysaccharides accumulation of Porphyridium purpureum CoE1, which was effectuated by inorganic salt starvation strategy whilst supplying rich carbon dioxide. At a culturing temperature of 25°C, the highest polysaccharide content (2.89g/L) was achieved in 50% artificial seawater on the 12th day. This accounted for approximately 37.29% of the dry biomass, signifying a 25.3% increase in polysaccharide production compared to the culture in 100% artificial seawater. Subsequently, separation, purification and characterization of polysaccharides produced were conducted. Furthermore, the assessment of CO2 fixation capacity during the cultivation of P. purpureum CoE1 was conducted in a 10L photobioreactor. This indicated that the strain exhibited an excellent CO2 fixation capacity of 1.66g CO2/g biomass/d. This study proposed an efficient and feasible approach that not only increasing the yield of polysaccharides by P. purpureum CoE1, but also fixing CO2 with a high rate, which showed great potential in the microalgae industry and Bio-Energy with Carbon Capture and Storage.

Enhancing phycocyanin yield from Spirulina sp. under salt stress using various extraction methods.

Phycocyanin, a blue-coloured pigment, predominantly found and derived from Spirulina sp., has gained researchers' interest due to its vibrant hues and other attractive properties like antioxidant and anti-microbial. However, the lack of reliable and sustainable phycocyanin extraction strategies without compromising the quality has hindered the scaling up of its production processes for commercial purposes. Here in this study, phycocyanin was extracted from wet and dry biomass Spirulina sp., using three different physical cell disruption methods (ultrasonication, homogenization, and freeze-thaw cycles) combined with two different buffers (phosphate buffer and acetate buffer) and water (as control). The result showed that the freeze-thaw method combined with acetate buffer produced the highest yield (25.013 ± 2.572mg/100mg) with a purity ratio of 0.806 ± 0.079. Furthermore, when subjected to 30% w/v salt stress, 1.9 times higher phycocyanin yield with a purity ratio of 1.402 ± 0.609 was achieved using the previously optimized extraction method.

Detecting directional epistasis and dominance from cross-line analyses in alpine populations of Arabidopsis thaliana.

The contribution of non-additive genetic effects to the genetic architecture of fitness, and to the evolutionary potential of populations, has been a topic of theoretical and empirical interest for a long time. Yet, the empirical study of these effects in natural populations remains scarce, perhaps because measuring dominance and epistasis relies heavily on experimental line crosses. In this study, we explored the contribution of dominance and epistasis in natural alpine populations of Arabidopsis thaliana, for two fitness traits, the dry biomass and the estimated number of siliques, measured in a greenhouse. We found that, on average, crosses between inbred lines of A. thaliana led to mid-parent heterosis for dry biomass, but outbreeding depression for estimated number of siliques. While heterosis for dry biomass was due to dominance, we found that outbreeding depression for estimated number of siliques could be attributed to the breakdown of beneficial epistatic interactions. We simulated and discussed the implication of these results for the adaptive potential of the studied populations, as well as the use of line-cross analyses to detect non-additive genetic effects.

Assessment of tolerance to glyphosate and glufosinate in genetically modified cotton shoots

Destruction of the harvest of cotton stalks should be done after it. However, destruction by ploughing prevents continuing with direct sowing, which makes chemical management an ally in soil conservation. The objective was to identify the most effective dose of 2,4-D, associated with different herbicides and the timing of administration for the control of transgenic cotton shoots for tolerance to glyphosate and glufosinate. The treatments consisted of the use of the herbicide 2,4-D, alone at doses of 670 and 1 340 g ha-1, and associated with the herbicides carfentrazone, flumiclorac, chlorimuron, flumioxazin and imazethapyr at three application times: 0 days after mechanical mowing (0 DAMM), 25 DAMM, and 0 DAMM + 25 DAMM. Regrowth evaluations were performed at 15, 30, and 45 days after the first and second applications, determining the dry biomass of the shoots. In terms of herbicide use time, the best results are obtained when they applied at 0 DAMM + 25 DAMM. Higher doses of 2,4-D (1 324 g ha-1) make it more efficient; in relation to herbicides, variations were perceived in their behavior depending on the time of evaluation, the application, and the dose of 2,4-D used. During the last measurement period, 45 days after application, 2,4-D+carfentrazone and 2,4-D+flumiclorac had the lowest dry shoot masses. The experiment was conducted in 2014. It was concluded that there is a lower rate of cotton regrowth when the application of the herbicides is repeated at 0 DAMM and 25 DAMM. The 1 324 g ha-1 dose of 2,4-D is more efficient. 2,4-D+carfentrazone and 2,4-D+flumiclorac promoted lower dry mass 45 days after administration of the treatments.

Coupling of phycoremediation and phytoremediation technologies to treat tannery effluents with rainwater dilutions

From tannery effluent (TE) severely polluted with heavy metals (HMs viz., Cr, Cu, Cd, and Pb), hydrophytic phytoextraction remains a challenge as transplanted plants succumb to death on facing acclimatization shock. Current study was aimed at diluting TE with harvested rainwater (HR) for improving HM phytoextraction potential of Phragmites australis (a hydrophyte) assisted with phycoremediation of coupled algae (viz., Oedogonium sp. and Pithophora sp.). The TE:HR dilutions (TEDs) 0, 25, 50, 75, and 100% (v/v) included three sets: set-1 included algae only, set-2 included P. australis only and set-3 included P. australis coupled with combined algal inoculum. Results showed that P. australis assisted with HR dilution and combined algal inoculum showed significantly greater uptake of HMs from each of the TEDs than respective control treatments. Combined algal application in the TEDs proved phycoremediation assistants based on their bioaccumulation factor (BF). The dry biomass of P. australis in TEDs applied with phycoremediation assistants remained greater than uninoculated ones. Overall, HM translocation factor (TF) of P. australis for Cr, Cu, Cd, and Pb remained ≥ 1. The study concludes that HM phytoextraction is substantially increased when concentrated TE is diluted with HR and assisted with phycoremediation of HM tolerant algae.

Optimum flow rate enhances the performance of lettuce (Lactuca sativa L.) in hydroponic culture

Poor substate flow rate affects the production of crops under hydroponic systems as contact and collision times of ions (nutrients) with roots is affected deciding nutrients uptake rate and quantity required for crop growth. Keeping in view, a study was conducted under hydroponic culture to obtain optimal flow rate for higher production of lettuce, which is an important leafy vegetable. Two lettuce varieties (Boston and Lollo Bionda) were subjected to 4 different flow rates (0.5, 1.0, 1.5, 2.0 L min-1) under completely randomized design (CRD) with factorial arrangement and replicated four times. The outcomes of the study suggest that performance of Lollo Bionda variety was better than Boston regarding root and shoot fresh and dry biomass, leaf number, area, length and width and head diameter and plant height. The same parameters kept on increasing with increase of flow rate and achieved maximum values at 1.5 L min-1. Beyond that flow rate the values for these parameters declined which indicated that the optimal flow rate for these 2 lettuce verities is 1.5 L min-1. Hence, it was concluded that for higher production of lettuce, the flow rate should be kept at 1.5 L min-1 in Nutrient Film Technique (NFT) using hydroponic system with environmental and substrate conditions mentioned in materials and method portion of this article.  

Plant Growth Promoting Rhizobacteria (PGPR) Isolated from an Arid Soil in Saudi Arabia Improve Maize Growth

The rhizosphere represents the main source of bacteria commonly referred to as rhizobacteria. Such beneficial rhizobacteria with plant-beneficial activities are generally defined as plant growth promoting rhizobacteria (PGPR). The aim of this study was to investigate the ability of native rhizobacteria (PGPR) isolated from an arid soil of date palm in Al-Qassim region, Saudi Arabia, to enhance plants growth. Maize (Zea mays L.) was used as model crop for this research. Maize seedlings roots were inoculated with Bacillus and Enterobacter bacteria. The seedlings showed significant increases in stem, leaf, and root growth. The maximal shoot lengths were obtained with strain (I2: Bacillus cereus) (95.41 cm) with an increase of 33.45 % compared to uninoculated control seedlings. The three isolates I2: Bacillus cereus, AZS2: Bacillus subtilis and commercial strain AZB: Azospirillum brasilense) caused a highly significant increase in the total number of leaves ranging from 10.9% to 12.7% compared to the uninoculated controls. Seedlings inoculated with AZS2: Bacillus subtilis strain exhibited the highest aerial dry biomasses with an improvement of more than 85 % (30.76 g) compared with uninoculated control plants and more than 62 % compared to uninoculated NaCl control plants. The inoculation treatment with I2: Bacillus cereus strain induced an improvement of more than 65 % (27.44 g) over uninoculated control and more than 45 % over uninoculated NaCl control. The strain AZS2: Bacillus subtilis produced the highest root dry weights, in comparison to other isolates and induced an improvement of 30.17% (26.06 g) compared to uninoculated control plants and 24.09% compared to uninoculated plants (NaCl control).The most effective rhizobacterial treatment in the dry biomasses of whole seedling (aerial dry biomass and root dry biomass) is AZS2: Bacillus subtilis strain which induced an improvement of 55% (56.83 g) compared to uninoculated plants and 42% compared to uninoculated plants (NaCl-control)...

Estimation of greenhouse gas emission due to open burning of rice straw using Sentinel data

In recent decades, Vietnam has gradually become a critical global rice producer. During that production process, residual straw becomes an environmental pollutant due to open burning, raising greenhouse gas emissions. This study combines the optical images of the Sentinel-2 satellite and the radar images of the Sentinel-1 satellite to estimate the dry biomass of rice and to determine gas emissions due to rice straw burning over the fields in Quoc Oai district, Hanoi city for urban environmental management purposes. Sentinel-2 images have been classified into the land covers, thereby identifying the areas of ​​rice cultivation and the areas of ​​burned straw. Meanwhile, the Sentinel-1 radar image has been used to calculate the dry biomass of rice due to its ability to penetrate clouds, an obstacle to optical images in tropical regions. Furthermore, a field trip during harvesting season allows us to measure aboveground dry biomass. Then, the analysis shows a high correlation between the backscatter V.V. and V.H. of the radar image and the in-situ dry biomass (R=0.923 and R2=0.852), with a relatively low average error (RMSE = 6.58 kg/100 m2). By linear regression method, the study found the total rice dry biomass of 28728.5 tons, which was obtained after the Summer rice crop 2020 for the whole Quoc Oai district, of which 2037.91 tons of rice straw have been burned, releasing a large amount of greenhouse gas emission with 2398.6 tons of CO2, 189.5 tons of CO, 18.8673 tons of PM10 dust, 17.2087 tons of PM2.5 dust and some other gases. The identical procedure has also been applied to the western region of Hanoi city center to estimate the amount of gas emissions. This study has proven the effectiveness of an approach and contributed to supporting urban managers in proposing appropriate policies to monitor and protect the environment.

Evaluation of the effect of organic fertilizers on the morphophysiological parameters and antioxidant compounds of Swiss chard (Beta vulgaris L.).

Objective: To evaluate the effect of organic fertilizers on the morphophysiological parameters and antioxidant compounds of Swiss chard (B. vulgaris L.) var. ‘Rainbow’ grown under greenhouse conditions. Design/Methodology/Approach: A completely randomized design was used with three treatments and 33 repetitions: T1 (poultry manure-based organic fertilizer (T1 AAC)), T2 (coffe pulp-based vermicompost (T2 LC)), and T3 (chemical fertilization (T3 FQ)). Plant height, stem diameter, number of leaves, leaf area, fresh biomass, dry biomass, chlorophyll A, chlorophyll B, total chlorophyll, carotenoids, total polyphenols, DPPH, and yield were evaluated. An analysis of variance and Tukey’s test (α=0.05) were used. Results: For most of the variables evaluated, the best results were obtained with the poultry manure-based organic fertilizer (T1 AAC) treatment. The antioxidant compounds and the quality of Swiss chard were influenced by organic fertilizers, with 0.21 mg Eq. gallic acid g-1 fresh tissue (ft), total chlorophyll of 19.5 µg g-1 (ft), and a yield of 6,150 kg·m2. Study Limitations/Implications: The mineral content of this vegetable was not evaluated. Findings/Conclusions: The use of poultry manure-based organic fertilizers can be an alternative nutritional management for Swiss chard cultivation.

Determining Eastern Red Cedar Biochar Soilless-Media Supplementation Rates for Potted Geranium and Petunia Production

The use of biochar in soilless media is becoming more common in greenhouse production. This study was conducted to evaluate Eastern red cedar biochar as a soilless-media supplement for the growth of geranium (Pelargonium graveolens L.) and petunia (Petunia sp. J.) as potted plants in greenhousese. Eastern red cedar biomass was produced at three different temperature ranges 300–350 °C, 400–450 °C, and 500–550 °C and applied at 15%, 30%, 45%, and 60% v/v to a soilless media plus a control. Additionally, Eastern red cedar (ERC) bark was also applied at 15%, 30%, 45%, and 60% v/v to a soilless media. The growth characteristics of the plants along with the physical and nutrient properties of the growth media were recorded. For physical properties, 100% soilless media had the greatest bulk density, 60% biochar at 400–450 °C showed the greatest total porosity, and 60% ERC bark showed the greatest air porosity. For geranium, 15% biochar at 500–550 °C showed the greatest height, water use efficiency, and shoot dry weight, while 15% biochar at 300–350 °C showed the greatest width. The greatest number of flowers was at 45% biochar at 500–550 °C. For petunia, 15% biochar at 300–350 °C showed the greatest height, and 15% biochar at 500–550 °C showed the greatest width. The greatest number of flowers and flower diameter was achieved with 100% soilless media. The 15% biochar at 500–550 °C had the greatest shoot dry weight and water use efficiency, and 60% biochar at 400–450 °C had the greatest root dry weight. Biochar treatment outperforms the ERC bark treatment for both species. Within biochar treatment, 15% biochar outperforms dry biomass, while for flowering, 100% soilless media performs best for petunia, and biochar performs best at less than 45% for geranium.

Cotton aphid (Aphis gossypii Glover: Aphididae) influence associated to water hyacinth nutrient (Pontederia crassipes Mart.: Pontederiaceae) in lath house conditions in Great Rift Valley of Ethiopia

The cotton aphid, Aphis gossypii Glover is a polyphagous herbivore known worldwide. The aphid infestation could be considered as a challenge to crops, but an opportunity for alien invasive weed management. Hence, this study was initiated to investigate the potential of cotton aphid on the management of water hyacinth. Aphid-infested water hyacinth plants were used as a stock for rearing the aphid in a lath house at Ethiopian Sugar Corporation, Research and Development Center, Wonji. After rearing, randomly collected 30 aphids were placed onto water hyacinth plants cultivated under three nutrient levels. Aphid population, water hyacinth biomass and percent nitrogen and phosphorus were analyzed. The water hyacinth treated with a high nutrient level had the highest (295.0) mean aphids on apical leaves followed by the middle (178.3) and basal (104.7) leaves. The water hyacinth subjected to medium and no aphid treatment had the highest dry (44.3 g) biomass. However, when treated with a low nutrient level and aphids resulted in the lowest dry (31.9 g) biomass. Nitrogen and phosphorus concentrations were found high in the water hyacinth that received a high nutrient and no aphid treatment. The presence of the aphids reduced the biomass and nutrient concentration of the invasive weed. The findings of the current study revealed that the cotton aphid affected the water hyacinth in the lath house conditions in Ethiopia.

Effect of Quizalofop-p-ethyl + Bentazone and Pendimethalin Herbicides on Weeds, Yield Components, and Yield of Mung Bean (Vigna radiata (L.) Wilczek) in Guragie Zone, South Central Ethiopia

Weeds significantly hinder mung bean production in Ethiopia. A field experiment conducted during the 2022 cropping season in Guragie Zone investigated the impact of pre- and post-emergence herbicides on weed control and mung bean (Vigna radiata (L.)) yield. The experiment utilized a randomized complete block design with three replicates and four treatments. The study revealed that the interaction between location and weed control methods significantly influenced weed density, dry weight, and control efficiency. Additionally, location and weed control methods significantly affected various mung bean growth parameters, including days to flowering and maturity, plant height, pod and seed numbers per plant, and grain yield. Meskan Wordea produced significantly higher pods per plant (14.4) and seeds per pod (9.73). Meanwhile, the weed-free check yielded the maximum number of pods per plant (20.38) and seeds per pod (11.68). Conversely, the weedy check exhibited the lowest values (7.17 pods and 6.43 seeds per pod). The weed-free check also achieved the highest grain yield (1412.9 kg ha−1), aboveground dry biomass (3309.2 kg ha−1), and harvest index (42.94%). Conversely, the weedy check yielded the lowest values. Financial analysis revealed that the combined application of Quizalofop-p-ethyl + Bentazone herbicide in Ezeha location resulted in the highest net profit (33602.3 ETB ha−1). Therefore, for optimal mung bean growth and yield in the study area, we recommend planting the Rasa variety with Quizalofop-p-ethyl + Bentazone herbicide in Ezeha location.

Trichoderma harzianum enhances root biomass production and promotes lateral root growth of soybean and common bean under drought stress

AbstractDrought stress (DS) is one of the main environmental stresses that determines crop productivity. It has been estimated that DS depresses over 40%–60% of soybean (Glycine max (L.) Merr.) and common bean (Phaseolus vulgaris L.) production worldwide, respectively. Although different agronomic strategies are sometimes implemented, the current goal in sustainable agriculture could involve the inoculation with native microorganisms to mitigate DS effects. A potential fungal candidate is Trichoderma, which is recognized as a ubiquitous soil inhabitant with growth‐promoting and biocontrol potentiality. However, its potential for mitigating the stress for water deficit is less well‐documented. Our objective was to evaluate the effect of inoculation with native Trichoderma harzianum strains on soybean and common bean growth under contrasting conditions of water availability. Seeds were independently inoculated (or not) with IB‐J15 and IB‐363 strains, and plants were submitted to DS or were kept under optimal irrigation (well‐watered, WW). In both legumes, the most evident effect after being inoculated was the modification of plant root architecture, the increase in root area and the development of lateral roots in plants under WW and DS conditions. In soybean, both Trichoderma strains had a positive inoculation response, both fresh and dry root biomass increased under WW, and remarkably under DS conditions. The main effect was an increase of about 110% in root dry weight under WW and, about 330% in DS in plants inoculated with IB‐J15 strain, meanwhile, plants inoculated with IB‐363 increased root dry weight 60% in WW and 177% in DS conditions. Notably in soybean, the inoculation with both Trichoderma strains increased the root area more than 70% in both WW and DS conditions. Common beans inoculated with IB‐363 under WW conditions, reached a positive inoculation responsiveness of around 247% in shoot dry weight biomass, and under WW both strains increased the root area more than 50%. Further, IB‐363 increased leaf area by 25% in WW and 72% in DS. Additionally, the in vitro co‐culture between both Trichoderma strains and nodulating Rhizobium etli and Bradyrhizobium japonicum E109 showed compatibility between microorganisms, since no inhibition of their growth was observed. We emphasize that plants inoculated with Trichoderma showed better resistance to water deficit, as seen by redistribution of photosynthates, prioritizing mainly, the development of the root system. © 2024 Association of Applied Biologists.

Juncus rigidus high biomass and cellulose productivity under wastewater salinity stress - A paradigm shift to the valorization of RO reject water

The use of water purifiers is intensively catching up and disposing of reverse osmosis reject water is of great concern. Reject water management using conventional methods is costly and harmful to the environment. To address this issue, the present study aims to utilize reverse osmosis reject wastewater using an eco-friendly approach. Juncus rigidus was treated with reject wastewater containing different salinity levels. Wastewater-treated plant dry biomass increased with increasing reject water salinity, and 625.3 g dry biomass recovered in treatment-B (~18,520 ppm). However, ~23,220 ppm wastewater salinity was lethal to the plants. The cellulose was extracted by alkali hydrolysis. The cellulose content in the wastewater-treated biomass was significantly higher in Treatment-B compared to both the control and Treatment-A (~12,744 ppm). The water salinity enhanced the cellulose (26.49 %) production in J. rigidus. Cellulose purity was confirmed using spectroscopic and thermogravimetric means. XRD shows highest crystallinity Index (77.29) with a d-spacing of 4.7 Å and 5.7 nm crystallite size in treatment-B. FTIR results reveal well-defined relevant peaks for OH, CH, CO, CH2, C-O-C, CO groups in treatment-B cellulose. Salinity impacts carboxyl groups in treatment B cellulose with a sharper and intense peak at 1644 cm−1 responsible for water absorption. Treatment-B exhibits higher thermal stability due to increased crystallinity. DSC shows endothermic depolymerization of cellulose with distinct peaks for different treatments. Morphological traits got better with increasing salinity with no adverse effect on cellulose. Salinity moderately affected the water absorption capacity of cellulose. All cellulose samples were devoid of gram-negative bacteria known by microbial test. This pioneering work underscores the plant's remarkable capacity not only to accomplish the circular economy by the valorization of wastewater obtained from various water purifiers for Juncus cultivation for cellulose production for diverse applications but also to generate income from wastewater.

Genotype-specific nonphotochemical quenching responses to nitrogen deficit are linked to chlorophyll a to b ratios

Non-photochemical quenching (NPQ) protects plants from photodamage caused by excess light energy. Substantial variation in NPQ has been reported among different genotypes of the same species. However, comparatively little is known about how environmental perturbations, including nutrient deficits, impact natural variation in NPQ kinetics. Here, we analyzed a natural variation in NPQ kinetics of a diversity panel of 225 maize (Zea mays L.) genotypes under nitrogen replete and nitrogen deficient field conditions. Individual maize genotypes from a diversity panel exhibited a range of changes in NPQ in response to low nitrogen. Replicated genotypes exhibited consistent responses across two field experiments conducted in different years. At the seedling and pre-flowering stages, a similar portion of the genotypes (∼33%) showed decrease, no-change or increase in NPQ under low nitrogen relative to control. Genotypes with increased NPQ under low nitrogen also showed greater reductions in dry biomass and photosynthesis than genotypes with stable NPQ when exposed to low nitrogen conditions. Maize genotypes where an increase in NPQ was observed under low nitrogen also exhibited a reduction in the ratio of chlorophyll a to chlorophyll b. Our results underline that since thermal dissipation of excess excitation energy measured via NPQ helps to balance the energy absorbed with energy utilized, the NPQ changes are the reflection of broader molecular and biochemical changes which occur under the stresses such as low soil fertility. Here, we have demonstrated that variation in NPQ kinetics resulted from genetic and environmental factors, are not independent of each other. Natural genetic variation controlling plastic responses of NPQ kinetics to environmental perturbation increases the likelihood it will be possible to optimize NPQ kinetics in crop plants for different environments.

Physio-biochemical Behavior and Health Effects of Pepper Plants Subjected to Lead Stress and Their Responses to Remediating Agents as Microbial Activity and Phosphorus

This work assessed the alleviating effects of bacteria (Bacillus subtilis) and phosphorus as environmentally friendly materials on the cultivation of pepper plants in polluted soil with lead (Pb) in forms of PbSO4, and Pb(NO3)2 at rates of 0, 1000, 2000 and 3000 µg Pb/g soil. Pot experiments were conducted to study the growth parameters, some physiological factors, biochemical constituents, and yield attributes, as well as the tolerance index (TI), translocation factor (TF), bioconcentration factor (BCF), and health effects [daily intake of heavy metals (DIM), health risk index (HRI), and carcinogenic risk (CR)]. Increasing the Pb concentration of all Pb salt used in soil severely affected the plant vegetative growth parameters. In comparison with other Pb salt forms, Pb(NO3)2 salt had a strong inhibitory impact. Additionally, the photosynthetic pigments in leaves were negatively impacted by all Pb salt forms. The application of Pb in all salt forms led to changes in the leaf water deficit (LWD), osmotic pressure, and membrane integrity and decreased the total water content, relative water content (RWC), transpiration rate, and leaf succulence. Pollution with Pb salts considerably decreased the yield constituents and various chemical properties of pepper, more so in the presence of Pb nitrate than in the presence of Pb sulfate type. A comparison of the concentration of Pb presence of Pb nitrate was greatly increased than the Pb sulfate in the whole plants. The safe limit of 0.3 mg/kg was exceeded by the Pb concentration in pepper fruits (6.3 and 4.3 mg/kg) cultivated in Pb-contaminated soil [with Pb(NO3)2 and PbSO4, respectively]. Additionally, Pb sulfate had a greater detrimental effect on Pb uptake in several plant organs than other Pb salt forms. The TI of pepper plants treated with salt types was >60% with PbSO4 (75.6%), whereas it was <60% with Pb(NO3)2 (35.2%). The BCF values of pepper plants in the polluted Pb soils varied from 0.10 to 0.41, indicating a moderate accumulator plant. At every level of Pb contamination with all Pb salt types, the sequence of Pb TF values was as follows: roots (TFr) > shoots (TFsh) > fruits (TFf), with TF values < 1. When compared with TFr and TFsh, TFs for shoot to fruits (TFf) had the lowest values (range, 0.07–0.22). The DIM, HRI, and CR values of pepper plants revealed that the Pb of fruit of stressed pepper plants is within safe limits. In addition to reducing the detrimental effects of intolerable Pb levels (2000 and 3000 µg Pb/g soil) on the majority of the aforementioned characters, adding Bacillus bacteria as a bio-agent and phosphorus as a chemo-agent to Pb-polluted soils also stimulated growth, increased yield, controlled plant water relations, protected photosynthetic pigments, and sharply decreased the Pb accumulation in plant organs. The Bacillus bacteria application resulted in some superior characteristics, such as root length, leaf number, leaf length, leaf area, leaf area index, fresh biomass, dry biomass, photosynthetic pigments, quantity yield attributes, reduction Pb accumulation in all plant organs, TI, TFr, TFf, BCF, in health effects trials, whereas phosphorus application improved plant height, leaf width, RWC, LWD, osmotic pressure, total soluble solids, acidity, total carbohydrates, total protein, and TFsh.

Impact of microbial consortium of Rhizobium tropici and Rhizobium mayense on the growth of Phaseolus vulgaris L.

The main objectives of the present investigation was to characterize and recognize potential indigenous Rhizobium spp. associated with red clover nodules, as well as to evaluate the influence of prospective rhizobia inoculation (individual and consortia) on common bean plant growth. Total of 8 rhizobia like bacteria were isolated and were investigated for their specific PGP traits, production of hydrolytic enzymes. Results revealed, four isolates synthesize IAA (22.3 ± 1.45 to 88.6 ± 1.45 μg mL−1), three isolates solubilized phosphate (40.69 ± 1.25 to 216.3 ± 1.31 μg mL−1), three isolates solubilized potassium, produced siderophore, and showed chitinase production, two isolates possess ACC deaminase activity, one isolate was able to solubilize zinc, 5 isolates produced β- 1, 3-glucanase (0.38 ± 0.005 to 2.82 ± 0.011 % units) and four isolates produced cellulase. Two bacterial isolates found to exhibit most of the PGP activities, were selected and identified on the basis of phenotypic, biochemical tests and 16S rRNA sequencing, as Rhizobium tropici IHTF-1 and Rhizobium mayense IHTF-2. Interaction of these potential rhizobium strains individually and consortia with common bean plants under greenhouse conditions boosted root and shoot length, fresh and dry biomass compared to un-inoculated control plants. SEM study revealed that both the strains, IHTF-1 and IHTF-2 colonized common bean roots. These results imply that Rhizobium spp., identified in this work, can be used as bio-inoculants to increase common bean plant production in a sustainable way.

Effect of Seed Size on Growth, Yield and Seed Quality of Jack Bean (Canavalia ensiformis (L.))

This research aimed to investigate the effect of seed size on growth, yield and seed quality of Jack beans cultivated in field conditions. The experiment was conducted at Faculty of Natural Resources and Agro-Industry, Kasetsart University Chalermphrakiat Sakonnakhon Province Campus. The experimental design was Randomized Complete Block Design (RCBD) with 3 replications and 3 treatments, and consisted of 3 different seed sizes of Jack bean (small, medium and large). The results indicated that seed size had no significant effect on growth (plant height, leaf number and weight of canopy). However, statistically significant differences (P<0.05) were found in fresh and dry biomass yields, whereas large seed size had the highest biomass yield without significant difference from seed yield. The 3 sizes of jack bean gave an average seed yield of 402.07 kg/rai. In term of seed quality, it was found that all 3 sizes of jack beans seed had no significant effect on physical quality and physiological quality in both standard germinations, germination index and a number of days used for germination. However, seed sizes had a significant effect on seedling biomass weight. The large seed had the highest weight (0.62 g/plant). Therefore, this study concluded that the three seed sizes (small, medium, and large) did not affect the growth, yield and seed quality of jack beans although the large size seed had the highest biomass yield.