Total Leaf Chlorophyll Content Research Articles

Influence of Super-Absorbent Polymer on Growth and Productivity of Green Bean under Drought Conditions

The water-retaining and yield-increasing capacity of super-absorbent polymer (SAP) are essential for soil remediation in arid and semi-arid areas. Water availability is an increasing challenge to plant development and crop yield. During the growing seasons in 2021 and 2022, the present study was conducted to evaluate the effect of the addition of different amounts of SAP on the development and yield of green beans (Phaseolus vulgaris L. cv Bronco) under varying water deficit stresses, compared with the control treatment without SAP and water deficit stress. The results demonstrated that a 50% reduction in water requirement (WR) resulted in significant decreases in leaf fresh weight, specific leaf area, leaf total chlorophyll content, pod number, leaf free water content, pod fresh weight per plant, and yield. Decreases were also found in pod total chlorophyll content, carotenoids, dry matter and total protein, leaf proline content, and crude fiber content. Additionally, leaf water saturation deficit was significantly increased under the stress compared with the full irrigation at 100% WR. However, irrigation at 75% WR increased pod contents of ascorbic acid, total sugars, and leaf bound water. The current study also indicated that addition of SAP significantly enhanced the above-mentioned growth characteristics under irrigation at 50% and 75% WR. Treatment with SAP at 3 g/plant was the most effective in mitigating the adverse effects of water deficiency, especially at the irrigation rate of 75% WR. Pearson’s correlation analysis showed significantly positive correlations between the growth parameters, as well as pod yield, under water stress and SAP. This study provides a promising strategy for green bean cultivation by adding SAP to soil to alleviate water shortage stress.

Vigna marina as a Potential Leguminous Cover Crop for High Salinity Soils

The beach bean (Vigna marina) exhibits robust growth in habitats characterised by sandy substrates, limited nutrient availability, and elevated saline levels. The utilisation of V. marina, a potentially beneficial leguminous cover crop, allows for its cultivation in regions characterised by soil salinity, hence facilitating the alleviation of environmental stress and the promotion of nitrogen fixation within the soil. A study assessed the feasibility of V. marina as a leguminous cover crop, in which this legume was cultivated in both coastal and inland soils. Pueraria javanica and Mucuna bracteata, widely recognised as established leguminous cover crops, were used as the control in this experiment. The observations involved were total plant biomass, nitrogenase activity, and leaf chlorophyll content of the host plants. The experiment consisted of five replicates arranged in a randomised complete block design, respectively. The effects of commercialised rhizobial compost on the development of the leguminous plants planted in both plots were also investigated. The results indicated that V. marina flourished in coastal and inland soils with the highest leaf chlorophyll concentration throughout the eight weeks of growth. It showed that V. marina has the potential to outperform the other two established leguminous cover crops when planted in highly salinised soils. The results also showed evidence that V. marina was an excellent potential leguminous cover crop, especially for any agricultural plots of high salinity soils, compared to the other two well-established leguminous cover crops, P. javanica and M. bracteata.

Improving mangoes' productivity and crop water productivity by 24-epibrassinosteroids and hydrogen peroxide under deficit irrigation

In nature, plants are frequently subjected to a wide range of abiotic stresses that drastically reduce crop productivity. Deficit in irrigation is one of the main factors of abiotic stresses that affect agricultural productivity. Nevertheless, not much research has been done on how to use water with brassinosteroids (Br) and hydrogen peroxide (H2O2)in deficit water conditions in order to reach comparatively good values of mango tree growth, productivity, and fruit quality as well as crop water productivity (WPC). A split-plot experiment in a complete randomized block system design study with 3 regulated deficit irrigation levels i.e. 100% IR (Irrigation requirement), 80% IR, and 60% IR was implemented in 2022 and 2023, each irrigation regime was combined with the foliar application of distilled water (control), 1 mg/L Br, 10 mM H2O2, 1 mg/L Br + 10 mM H2O2. Foliar treatments were applied at 3 different phenological stages: flower bud induction and differentiation, full bloom, and beginning of fruit set. The results showed that fruit shape index and acidity significantly improved as irrigation volume increased, however, the proportion of fruit mineral content and fruit chemical characteristics was inversely correlated with the volume of water. Meanwhile, moderate regular deficit irrigation (80% IR) achieved marked increases in leaf minerals and total chlorophyll content, fruit quality, yield, and water use efficiency. Drought stress (60% IR) significantly decreased fruit set, fruit retention, yield traits, and fruit physical and chemical properties, at the same time, significant improvements in the content of stress indicators (proline, total phenols, and carotenoids) were observed compared with control. All treatments with Br and H2O2 alone or in combination under drought stress had a pronounced effect in this regard. Overall, foliar spray of 1 mg/L Br+10 mM H2O2 was the most powerful treatment that emended the unpropitious effect of water stress.

Light Intensity Modulates the Functional Composition of Leaf Metabolite Groups and Phyllosphere Prokaryotic Community in Garden Lettuce (Lactuca sativa L.) Plants at the Vegetative Stage.

Light intensity primarily drives plant growth and morphogenesis, whereas the ecological impact of light intensity on the phyllosphere (leaf surface and endosphere) microbiome is poorly understood. In this study, garden lettuce (Lactuca sativa L.) plants were grown under low, medium, and high light intensities. High light intensity remarkably induced the leaf contents of soluble proteins and chlorophylls, whereas it reduced the contents of leaf nitrate. In comparison, medium light intensity exhibited the highest contents of soluble sugar, cellulose, and free amino acids. Meanwhile, light intensity resulted in significant changes in the composition of functional genes but not in the taxonomic compositions of the prokaryotic community (bacteria and archaea) in the phyllosphere. Notably, garden lettuce plants under high light intensity treatment harbored more sulfur-cycling mdh and carbon-cycling glyA genes than under low light intensity, both of which were among the 20 most abundant prokaryotic genes in the leaf phyllosphere. Furthermore, the correlations between prokaryotic functional genes and lettuce leaf metabolite groups were examined to disclose their interactions under varying light intensities. The relative abundance of the mdh gene was positively correlated with leaf total chlorophyll content but negatively correlated with leaf nitrate content. In comparison, the relative abundance of the glyA gene was positively correlated with leaf total chlorophyll and carotenoids. Overall, this study revealed that the functional composition of the phyllosphere prokaryotic community and leaf metabolite groups were tightly linked in response to changing light intensities. These findings provided novel insights into the interactions between plants and prokaryotic microbes in indoor farming systems, which will help optimize environmental management in indoor farms and harness beneficial plant-microbe relationships for crop production.

Conservation tillage and residue management practices in rice improves stress tolerance of succeeding vegetable pea by regulating physiological traits in Eastern Himalayas

The majority areas of valley lands in the Himalayan foothills remains fallow after the rice harvest. Recycling of plant biomass with conservation tillage may help in enhancing soil water availability, crop physiological function and productivity under moisture stress hill environments of this region. The present study focused on three tillage practices viz., no-till (NT), minimum tillage (MT) and conventional tillage (CT) and five nutrient management (NM) practices viz., 100 % NPK, 50 % NPK, 50 % NPK + in-situ residue retention (ISRR), 50 % NPK + weed biomass (WB) and 50 % NPK + green leaf manure (GLM) in rice and their residual effect on physio-biochemical properties, yield attributes and produce quality traits of succeeding pea varieties (Arkel and Prakash). Results revealed that total leaf chlorophyll content in vegetable pea varieties Arkel and Prakash was 12.0 and 11.5 % higher under no-till (NT) followed by 11.9 and 10.6 %, respectively under minimum tillage (MT) as compared to conventional tillage (CT) in rice. Similarly, application of 50 % NPK+ green leaf manure (GLM) and 50 % NPK+ weed biomass (WB) enhanced total leaf chlorophyll content in pea by 6.50–8.17 % and 3.93–5.48 % for pea varieties Arkel and Prakash, respectively. Photosynthetic rate and leaf dry weight were found 40.4 and 80.2 % higher under MT in Arkel whereas transpiration rate (E) and shoot dry matter were 33.1 and 19.3 % higher in Prakash under MT. Leaf water potential and root-to-shoot ratio were found 22.6 and 16.5 % higher in Prakash under MT and NT compared to CT respectively. Leaf temperature and stomatal conductance were 8.67 % lower and 9.8 % higher under MT in Prakash respectively as compared to CT, whereas 4.8 and 13.0 % higher under 50 % NPK +GLM and 50 % NPK+WB as compared 100 % NPK. Leaf cell viability was 22.5 and 20.1 % higher under MT whereas leaf MDA content was 29.9 and 28.3 % higher under MT in Arkel and Prakash respectively. Leaf relative water content was significantly higher to the tune of 25.7 and 22.4 % under NT compared to CT whereas leaf cell membrane integrity was 41.3 and 40.4 % higher under NT for Arkel and Prakash. Higher pod protein was noticed under MT along with 50 % NPK+GLM (13.1 %), whereas total soluble sugar was recorded highest under NT with 50 % NPK+GLM (21.1 %) in Prakash and MT with 50 % NPK+GLM (18.3 %) in Arkel. However, in both varieties, lower TSS was recorded under CT and with 50 % NPK (14.2 and 11.2 %) and the reducing sugar was maximum under the application of 50 % NPK+WB as compared to 100 % NPK alone. For both varieties of pea, green pod yield was recorded highest under MT (4.76 & 5.89 t/ha) as compared to CT (4.76 & 6.17 t/ha) and NT (4.76 & 5.55 t/ha). While 50 % NPK+WB has recorded significantly highest green pod yield of Arkel, 50 % NPK+ GLM has caused the highest yield of Prakash. PCA executed on physiological traits explained the total variability to the tune of 85.50 %, thereby extracting three PC's viz., PC 1 (62.63 %), 12.58 %) and 10.28 %, respectively. Thus, the adoption of MT in rice followed by NT in winter pea with the application of 50 % NPK+WB or 50 % NPK+GLM is promising for better physiological traits and subsequently favoring the grain yield of pea under stressful hill environments of Eastern Himalaya.

Evaluation of tree species using Air Pollution Tolerance Index for urban landscaping in Delhi

Air pollution which negatively impacts both human health and the environment is a mountainous challenge before policymakers and city planners in urban areas. Urban landscaping with effective pollution-combating tree species is one of the soundest strategies to mitigate pollution adversaries. However, not all tree species are equally suitable for urban environments due to varying levels of tolerance to air pollution. This study has been designed to evaluate the physiological and biochemical responses of seven commonly occurring tree species in the Talkatora garden (TG) and Income Tax Office (ITO) representing non-polluted and polluted locations in Delhi, respectively applying Air Pollution Tolerance Index (APTI). The current research study was carried out during 2021–22 at the Division of Floriculture and Landscaping, ICAR-Indian Agricultural Research Institute, New Delhi. In tree species understudy, it was recorded that the pH of leaf extract, total chlorophyll, and relative water content was lower in the winter season than summer season except for the ascorbic acid. Ficus religiosa with the highest APTI value (23.23) followed by Pongamia pinnata (20.85) were found most tolerant tree species to air pollution in Delhi during the winter season at the polluted (ITO) and non-polluted (TG) location respectively with a reverse trend for the summer season. Polyalthia longifolia was found most sensitive (bioindicator plant) to air pollution among the seven trees under study owing to the lowest APTI values (11.14 and 12.58) across the seasons at non-polluted (TG) and polluted (ITO) locations respectively. Furthermore, Ficus religiosa with the highest APTI across the locations and seasons was assessed as the best performer, hence, could be the most efficient option for landscaping in polluted and non-polluted areas.

Effect of bioaugmented Linz-Donawitz slag and biochar on physiological and yield attributes of wheat (Triticum aestivum)

Industrial wastes and agricultural by-products are increasingly used in crop production as supplements along with fertilizers. An experiment was conducted during the winter (rabi) seasons of 2021 and 2022 at the research farm of the ICAR-Indian Agricultural Research Institute, New Delhi to determine the individual and combined effects of bioaugmented Linz-Donawitz (LD) slag and biochar on physiological and yield attributes of wheat (Triticum aestivum L.) variety HD 2967. Bioaugmented products with cow-dung, LD slag and biochar in different combinations were prepared in laboratory scale and applied in crates. All the treatments were applied with 100%RDF except control. Growth parameters such as total leaf area, chlorophyll content, NDVI; and leaf photosynthetic attributes such as net photosynthetic rate, stomatal conductance and transpiration rate were affected by bio-augmentation. Our study reported an increase in total leaf area (18.2–21.3%), chlorophyll content (26.5–31.0%), net photosynthetic rate (93.2%), stomatal conductance (61.3%), transpiration rate (24.7%) in bioaugmented treatments with LD slag and biochar over 100%RDF. A yield increase of 25.6 and 27.1% was found in bioaugmented treatments with a combination of LD slag (2 t/ha) and biochar (1 t/ha) over 100%RDF during 2021 and 2022, respectively. No. of spikes, grains per spike and dry biomass weight were positively influenced by bioaugmentation. The bioaugmented treatments with a combination of LD slag and biochar gave significantly higher grain yield, followed by bioaugmented LD slag compared to bioaugmented biochar alone in the respective application rate of treatments.

Karakter Morfo-agronomi Tanaman Cabai Merah (Capsicum annum L.) Fase Awal Vegetatif pada Kondisi Stres Jenuh Air

Vegetable cultivation in tropical riparian wetland is currently suboptimal due to unpredictability of water dynamics. Chili pepper is a fruity vegetable that is often cultivated in tropical riparian wetland but is often constrained by conditions of excessive water saturation, such as shallow water tables, waterlogging and submergence in the transition period (dry to rainy season). The aim of this research was to study the morpho-agronomy of varieties of chili peppers under waterlogging stress during the early vegetative stage. A Plot Design was used in this experiment. The main plot consisted of (1) control (field capacity, regularly watering) and (2) waterlogging (simulated by adding water to the growing substrate until a thin layer of water was visible above the substrate surface during four days, followed by a seven-day recovery time during seven days). The subplot consisted of three chili pepper varieties, namely Laris, Romario, and Takanotsume (Japanese variety). Results of this study revealed that waterlogging stress significantly affected root length, number of leaves, total leaf area, chlorophyll content (SPAD), root fresh weight, shoot fresh weight, root dry weight, and shoot dry weight after stress and after recovery time. Meanwhile, chili pepper varieties were only significantly affected the total leaf area and chlorophyll content (SPAD). The total dry weight of Romario and Takanotsume before stress, after stress and after recovery did not significantly increase under waterlogging stress, whereas the total dry weight of Laris was precisely increased, indicating that vegetative growth is continuing. The Laris was categorized as one of chili pepper varieties that had medium tolerance to waterlogging stress at the early vegetative stage. 
 
 Keywords: Capsicum annum L., soil plant analyses development, total dry weight, waterlogging

Effect of Pruning on Morpho-physiological Characters and Yield of Pumpkin (Cucurbita moschata)

The present study was carried out at the Instructional cum Research Farm, Department of Horticulture, Biswanath College of Agriculture, Assam Agricultural University, Biswanath Chariali with an aim to study the morpho-physiological characters and yield as influenced by pruning in pumpkin. Pumpkin is an important commercial vegetable crop of Assam which is cultivated mainly during rabi season.The treatments were: T1(Trimming of growing tip of the primary vine at 8th node stage), T2(Trimming of growing tip of the primary vine at 10th node stage), T3(Trimming of growing tip of the primary vine at 12th node stage), T4(Trimming of growing tip of the secondary vine at 6th node stage), T5(Trimming of growing tip of the secondary vine at 8th node stage), T6(Removal of all tertiary vines), T7(Retention of two tertiary vines) and T8(control without pruning). The study revealed that among the treatments, T4 recorded the highest primary vine length and inter-nodal length of primary vine at 60, 90 DAS and at 1st harvest. Number of primary vine was found to be highest under T5 whileT3 recorded maximum number of secondary vines, inter-nodal length of secondary vines, the highest total leaf chlorophyll content, relative leaf water content, leaf area index and maximum fruit yield. Therefore, trimming of growing tip of the primary vine at 12th node stage can be suggested for pumpkin to get maximum yield.

β-Aminobutyric acid enhances salt tolerance of African marigold by increasing accumulation rate of salicylic acid, γ-Aminobutyric acid and proline

African marigold (Tagetes erecta L.) is one of most cultivated warm-season flowers which is used as cut flower, potted flower or margin flower. Nowadays, one of the most common issues of landscaping is sensitivity of ornamental plants to salinity of soil or irrigation water. In order to investigate the role of β-Aminobutyric acid (BABA) treatments in alleviation of adverse effects of salt stress on African marigold, a factorial experiment was conducted based on completely randomized design with 3 replications during 2022–2023. The experimental treatments included different concentrations of BABA (0, 4, 8 and 12 mM) and different levels of salinity (0, 50, 100 and 150 mM NaCl). Results demonstrated that the negative effects of salinity on marigold characteristics increased by increasing the salinity level, but BABA treatments effectively alleviated the adverse effects. Fresh and dry weight of shoots and root, leaf relative water content, total chlorophyll and carotenoid content, the activity rate of phenylalanine ammonia lyase, catalase and superoxide dismutase, and the accumulation rate of salicylic acid, γ-Aminobutyric acid (GABA) and proline were significantly increased by treatment of marigold plants with BABA 8 mM. Also, this treatment maintained plant phenol and protein content, and reduced H2O2 content, malondialdehyde content and electrolyte leakage under salinity conditions. Accumulation of salicylic acid, GABA and proline caused by BABA treatment could probably be one of most important mechanisms of enhancing salt tolerance rate of marigold plants in this study, therefore, it is recommended to use this treatment as innovative and efficient technique to overcome salinity effects on African marigold plants.

The effect of arbuscular mycorrhizal inoculation and plant growth-promoting rhizobacteria on maize (Zea mays L.) under boron toxicity stress

A greenhouse study was conducted to investigate the effect of arbuscular mycorrhiza fungus and plant growth-promoting rhizobacteria on maize (Zea mays L.) yield and boron (B) uptake under excessive B concentrations. Four levels of B (0, 10, 20 and 40 mg kg-1 soil) and four levels of microbial inoculation (non-inoculation, Rhizophagus intraradices, Micrococcus yunnanensis and co-inoculation) were applied. In general, elevated B decreased the maize relative yield, plant dry weight, plant height, total leaf area and chlorophyll content. The highest B uptake was recorded in the 20 mg kg-1 B treatments, whereas the lowest uptake was in B treatments of 0 and 40 mg B kg-1. Excessive B supply increased the proline content and electrolyte leakage of maize leaves. Microbial inoculation did not change the yield of B-stressed plants. In addition, mycorrhiza inoculation and co-inoculation increased the shoot and root B uptake. Maize plants growing at high B concentrations with or without microbial inoculation showed leaf edge burning and necrosis when compared with control treatments. Microbial inoculation improved the maize yield under B stress up to 20 mg B kg-1. Thus, inoculation with arbuscular mycorrhiza and plant growth promoting rhizobacteria can increase the maize tolerance under B toxicity. Nonetheless, the inoculation of bacterium and arbuscular mycorrhiza had a more alleviative effect when the plants were exposed to excess B.

Plant growth promoting rhizobacteria incorporated soilless substrates – A potential arena for high quality nursery production of ornamentals

Nursery raising of ornamental flowering annuals using soilless substrates is becoming a lucrative industry worldwide. Pakistan, being an agricultural country, still doesn't have its own cheaper and sustainable soilless substrates for high quality nursery production. Therefore, a study was conducted at University of Agriculture, Faisalabad, Pakistan and Purdue University, West Lafayette, IN, USA, for development and evaluation of a cheaper, sustainable, and easily available soilless substrate using agricultural by-products along with its value addition by inoculating it with plant growth promoting rhizobacteria. For this purpose, coco-coir, rice hulls ash and composted sugarcane pressmud were combined in ratio of 1:1:1; v/v/v and were inoculated with Bacillus (MN-54), Enterobacter (MN-17) and Trichoderma species in 108 CFU mL−1 and 107 CFU mL−1 solutions. These inoculated treatments along with uninoculated treatment, a negative control (sand: silt; 1:1, v/v) were evaluated for their physico-chemical and nursery raising aspects for ‘Inca’ marigold and ‘Giant Dahlia Flowered’ zinnia. The study revealed that Enterobacter MN-17 (107 CFU mL−1) inoculated substrate had highest water holding capacity (72.9 %), total porosity (81.04 %) and organic matter contents (92.9 %). Whereas, Trichoderma spp. (108 CFU mL−1) inoculated substrate had better electrical conductivity (1.59 dS m−1) and pH (5.64) and resulted in highest final germination percentage (93.6 %), with greatest seedling vigor index (2195), seedling shoot length (10.2 cm), root length (12.5 cm) and leaf total chlorophyll contents (57.4 SPAD) in marigold. However, in zinnia, Enterobacter MN-17 (107 CFU mL−1) inoculated substrate resulted in highest germination percentage (98.3 %), greatest seedling vigor index (3302), seedling root length (15.8 cm) and leaf total chlorophyll contents (55.8 SPAD), whereas same strain with 108 CFU mL−1 took shortest time for mean germination (3.8 days). In conclusion, substrate enriched with Enterobacter MN-17 (107 CFU mL−1) or Trichoderma spp. (108 CFU mL−1) may be used to produce high quality ornamental flowering annuals nursery.

The Impact of Organic Fertilizers and Stimulants on Vegetative Growth of Pomegranate Seedling Leaves (cv. Salimi)

The experiment was conducted in 2022 at the Department of Horticulture and Landscape Engineering, College of Agriculture, Tikrit University, to determine the impact of organic fertilizer and stimulants on the vegetative growth of pomegranate seedlings in their first year of permanent cultivation. The study treated seedlings with auxins IBA and NAA at 100 and 200 mg L-1, glucose sugar at 5000 mg L-1, and Commercial stimulation Taravert Evo at 6 and 12 ml seedling-1. The experiment used a Randomized Complete Block Design (R.C.B.D) with two factorial elements. The experimental unit comprised one seedling, and Duncan’s multiple test at 5% was used to compare the averages. The treatment with organic fertilizer at 40% increased vegetative growth characteristics like leaf area, total leaf area, seedling height and diameter, and leaf chlorophyll content, while the stimuli increased them. It caused substantial changes in vegetative development (leaf area, total leaf area, and plant height). Stimuli treatment significantly altered vegetative development (leaf area, total leaf area, plant height, and chlorophyll content). The analyzed parameters’ interactions significantly affected vegetative features as leaf area, total leaf area, seedling diameter, and leaf chlorophyll content.

Assessment of air pollution tolerance potential of selected dicot tree species for urban forestry.

Air pollution is one of the killers of our age especially for the urban areas. Urban forestry which involves planting more trees has been considered as one of the prominent strategies to mitigate air pollution. Identification of trees tolerant to air pollution is important for plantation drives being organized across the country. The present study aimed to compare the air pollution tolerance potential of 46 tree species growing in Guru Nanak Dev University (GNDU) campus, Amritsar, using two indices, viz., Air Pollution Tolerance Index (APTI) and Anticipated Performance Index (API). APTI is based on four biochemical parameters, viz., relative water content, leaf extract pH, total chlorophyll, and ascorbic acid contents of leaf samples, whereas API takes into consideration morphological and socioeconomic values of plant species along with their APTI. Based on APTI values calculated for 46 tree species, only 2 tree species, viz., Psidium guajava (46.26) and Cassia fistula (41.83), were found to be tolerant to air pollution, while 25 species showed intermediate tolerance. API scores revealed one tree species, namely, P. guajava, as an excellent performer, 8 species as very good performers, and 28 species as moderate to good performers against air pollution. In conclusion, tree species like Alstonia scholaris, C. fistula, Ficus tsjakela, Grevillea robusta, Kigelia africana, Mangifera indica, Melia azedarach, P. guajava, Pongamia pinnata, Pterospermum acerifolium, Putranjiva roxburghii, Syzygium cumini, Terminalia arjuna, and Toona ciliata can be considered as most desirable for plantations in areas around GNDU campus.

Environmental pollution biomonitoring around a cement factory based on the Air Pollution Tolerance Index of some tree species.

The present study examined the ability of Quercus castaneifolia C.A.M., Parrotia persica C.A.M., and Carpinus betulus L. for environmental pollution biomonitoring based on the Air Pollution Tolerance Index (APTI). Four leaf traits, total leaf chlorophyll content, leaf extract pH, ascorbic acid content, and relative water content of leaf, were used to compute the APTI values. The study was conducted at five sites in the Hyrcanian forests at different distances from a cement factory close to the Neka city, northern Iran. Based on the results, a 22.5, 30.1, and 25.8% decrease was thus recorded in total chlorophyll content for Q. castaneifolia, P. persica, and C. betulus, respectively, compared to the reference site. However, ascorbic acid content shows an increment of 179.8, 116.8, and 97.3% for P. persica, C. betulus, and Q. castaneifolia, respectively, in the polluted sites as compared to the reference site. The relative water content of P. persica was significantly higher than of Q. castaneifolia and C. betulus in all studied sites. APTI was significantly different among the species, and P. persica was highly tolerant to air pollution, with the highest values of APTI ranging from 11.8 to 16.9. The APTI values of Q. castaneifolia ranged from 9.5 to 11.3 and showed an intermediate tolerance to air pollution. Also, the most sensitive species to air pollution was C. betulus, with a range of 6.6-7.9 in APTI values. Based on APTI values, it can be suggested that P. persica can be used as a biomonitor, while C. betulus can be used as a bioindicator for atmospheric dust deposition and heavy metal pollution.

The impact of two bacterial species and five aqueous plant extracts on yield and yield components of rice (Oryza sativa L.) and surof (Echinochloa crus-galli L.)

Chemical exudates from some plants to the environment have been reported as causative agents of adverse effect on growth of neighboring plants and thus affecting normal growth in their natural environment. The mode of action of Chemical exudates on plants is involves a large number of biochemical reactions. This research aimed to investigate the effect of foliar application of different levels of two bacterial species and five aqueous plant extracts on the yield and yield components of Oryza sativa L. and Echinochloa crus-galli L. This research was conducted as a factorial based on randomized complete block design (RCBD) with three factors with three replications during the 2017–2018 crop year. The main factor included aqueous extracts of Sorghum (Sorghum bicolor L. Moench), Broccoli (Brassica oleracea var. Italica), Nettle (Urtica dioica), Eucalyptus (Eucalyptus globulus Labill), Elderberry (Sambucus nigra L.), and Streptomyces sp-albos containing thaxtomin, Xanthomonas campestris, and control (without aqueous plant extracts and surfactant). The sub-factor includes foliar application treatment with different levels of zero (control), 5, 10, and 15% of extracts, and the third experimental factor included Oryza sativa L. and E. crus-galli L. The results indicated the plant height, leaf area index (LAI), grain yield, biological yield, chlorophyll a, chlorophyll b, total chlorophyll, and grain protein content decreased, and the grain starch content increased with increasing the extract concentration; the highest effect was obtained at 15% of extracts. The lowest value of leaf area index (3.13) were found in higher concentration of X. campestris followed by Elderberry extract (5%, 10% and 15%) and Nettle (10%) extracts. It was also found that using extract reduced yield characteristics and components of Oryza sativa L., E. crus-galli L., and Elderberry extract showed the highest negative effect. According to the results, Oryza sativa L. had higher plant height, LAI, grain yield, biological yield, harvest index, chlorophyll, grain protein content, and grain starch content than E. crus-galli L. In all extractions, control treatment had the highest number of panicles plant−1 in both plants (rice and E. crus-galli L., 260.1 and 117.1 mg g−1 FW). The results suggested that various extracts, especially Nettle, and 15% of Elderberry can control E. crus-galli L. at the germination stage under field conditions.

LEAF PIGMENT AND TOTAL CARBOHYDRATE CONTENT AT EARLY STAGES OF HERITIERA FOMES BUCH. SEEDLINGS GROWN AT THREE SALINE ZONES OF THE SUNDARBANS, BANGLADESH

The experiment was conducted to find the leaf pigments and carbohydrate content in Heritiera fomes at different growth stages exposed to different salinity levels in the Sundarbans areas, Bangladesh. Three leaf pigments, viz., chlorophyll a, chlorophyll b, and carotenoid, total chlorophyll, and total carbohydrate content of Heritiera fomes Buch. Ham seedlings were determined in the leaves grown in the oligohaline, mesohaline, and polyhalite zones at early (6 and 9 months) and survival ages (30 months) following standard methods. Leaves from seedlings at the age of 30 months (survival aged) show relatively high leaf pigments than that of the 6 and 9-month-old seedlings grown in the three saline zones. Total chlorophyll content in leaves was found low in the oligohaline zone at the early and survival ages, but higher in the polyhalite zone at the early ages, and higher in the mesohaline zone at the survival age. Chlorophyll b was relatively higher than chlorophyll a. Leaves of 30 months seedlings showed relatively higher chlorophyll a than chlorophyll b at the polyhalite zone, but higher chlorophyll b was noted at the mesohaline zone. The highest content of total carbohydrates was observed in the shoots of 6, 9, and 30 months ages H. fomes seedlings in the polyhalite zone, while the lowest was in the mesohaline zone. At the same age periods in the mesohaline zone, the roots of the H. fomes seedlings showed relatively higher carbohydrate content and lower at the 30 months seedlings in the all saline zones. Chlorophyll a was found to be more sensitive than chlorophyll b and carotenoid at different salinity levels tested. Higher carbohydrate content was discovered as an additional mechanism to prevent salt toxicity at early ages of high saline conditions (polyline zone).

Effect of Fruit Peel Biochar on Growth and Yield of Tomato (Solanum lycopersicon Mill.) and Country Bean (Lablab purpureus) in Acidic Soil of Sylhet, Bangladesh

The potential of biochar as a soil conditioner has been approved by scientists worldwide due to its large surface area, high water retention capacity, slow nutrient releasing nature and liming ability; and it might also help to get desirable crop yield in problem soil like acidic soil. Hence, an experimental field trial was operated at the research field of the Department of Agroforestry and Environmental Science, Sylhet Agricultural University, Sylhet to evaluate the performance of banana peel biochar (BB) and orange peel biochar (OB) in the growth and yield of tomato (Solanum lycopersicon Mill.) and country bean (Lablab purpureus) under acidic soil conditions. In case of tomato, plant height (PH), number of leaves plant-1 (NLP), leaf length (LL), and stem diameter (SD) in treatments having different levels of biochar were significantly higher than the control. The maximum PH (72.20 cm), NLP (21), LL (35.66 cm), SD (9.05 cm), and total leaf chlorophyll content (TLCC) (50.56 µmol m-2) of tomato were found in T7 (3% OB w/w + CF) followed by T4 (3% BB w/w + CF) whereas in country bean, the PH (373 cm), NLP (34), branch number (BN) (3), and TLCC (36.65 µmol m-2) were also recorded in T7 followed by T4. The root length (RL) (43.5 cm) and fresh root weight (FRW) (14 g) of country bean were the maximum at T7, followed by T5 (1% OB w/w + CF). According to the results, positive effects of BB and OB application were observed on all the yield parameters of country bean and tomato. The number of pod plant-1 (NPP) (384), individual pod weight (IPW) (5.78 g), total pod weight plant-1 (TPWP) (2220 g), and pod length (PL) (10.57 cm) of country bean were also found to be highest in T7, followed by the T4. Similarly, the highest NFP (37), IFW (55 g), and TFWP (1980 g) of tomato were noted in T7, followed by T4. After the cultivation of country bean and tomato, a significant increase in the soil pH was noticed at T3 (2% BB w/w + CF), T4, T6 (2% OB w/w + CF) and T7 in respect of the control. Therefore, the findings of the study suggest that both BB and OB could have a positive impact on growth and yield components of tomato and country bean by altering soil pH of acidic soil.

Effect of Co-application of Different Biochars and Inorganic Fertilizers on the Growth and Yield of Okra (Abelmoschus esculentus L.)

To manage necessary amount of food for the growing world population, it is very important to maintain fertility of usual arable land as well as to bring problem soils including sandy soil under coverage of regular crop cultivation. In this context, biochar is a very promising option as soil conditioner and therefore, a plant growth trial in pot was operated at the net house of the Department of Agroforestry and Environmental Science, Sylhet Agricultural University, Sylhet to evaluate the influence of tea waste and sugarcane bagasse biochar on the morphology, yield and yield contributing traits of okra (Abelmoschus esculentus) in sandy soil. The experimental set-up was arranged following randomized complete block design with three replications under eight treatments. The treatments were: T0 (CK, Control, no amendment), T1 (CF, Chemical fertilizers), T2 (2.5 % TWB (tea waste biochar) + CF), T3 (5% TWB + CF), T4 (10% TWB + CF), T5 (2.5% SBB (sugarcane Bagasse biochar) + CF), T6 (5% SBB + CF); and T7 (10% SBB + CF). The results revealed that the different morphological characteristics like plant height (PH), number of leaf plant-1 (NLP), leaf length (LL), plant fresh weight (PFW), and stem diameter (SD) showed no significant difference among the treatments. The highest PH (107.33 cm) and RL (70.67 cm) were found in T0 (CK) whereas the maximum LL (27.33 cm), SD (10.38 mm), and fresh root weight (FRW) (19.67g) were noted in T3. The maximum number of leaves plant-1 (NLP) (20) and PFW (110.67 gm) of okra were observed in T2 and T6, respectively. In case of total leaf chlorophyll content (TLCC), the maximum value was determined in T4 (47 µmol m-2), but the treatments were not significantly different from each other. The number of pod plant-1 (NPP) (23.7), pod length (PL) (18 cm), individual pod weight (IPW) (18 g), number of seed pod-1 (NSP) (45) and pod weight per plant-1 (PWP)(425 g) of okra were found to be highest in T7, followed by T4 and T6. The yield and yield contributing characters of okra showed significantly higher value for biochar treatments (T2 - T7) over to the control (T0) and sole chemical fertilizer treatment (T1). After the cultivation of okra, the highest pH value (7.2) was found in T7, followed by T6. The results of this study might contribute to enlarge the prospects of biochar application in the production of okra and other crops in both normal and less fertile soils.

Dynamics of Herbicidal Potential: Effects of Two Bacterial Species and Five Aqueous Plant Extracts on Yield and Yield Components of Rice (Oryza sativa L.) and Surof (Echinochloa crus-galli L.)

This research aimed of investigate the effects of foliar applications using different levels of herbicidal potential from two bacterial species and five aqueous plant extracts on the yield and yield components of Oryza sativa L. and Echinochloa crus-galli L. The study followed a split factorial design based on randomized complete block design (RCBD) with three factors and three replications during the 2017-2018 crop year. The primary treatments consisted of aqueous extracts from Sorghum, Broccoli, Nettle, Eucalyptus and Elderberry, as well as Streptomyces sp-albos containing thaxtomin, Xanthomonas campestris, and control s (without aqueous plant extracts and surfactant). The secondary factor involved foliar application treatments with varying levels of concentration, including zero (control), 5, 10, and 15 per thousand extracts and the third experimental factor included Oryza sativa L. and Echinochloa crus-galli L. The findings revealed that as the extract concentration increased, plant height, leaf area index (LAI), grain yield, biological yield, chlorophyll a, chlorophyll b, and total chlorophyll contents decreased. Conversely, grain starch content increased with higher extract concentrations, with the most pronounced effects observed at 15 per thousand extract concentration. It was also observed that the use of extracts led to reduced yield characteristics and components in both Oryza sativa L. and Echinochloa crus-galli L. Among the extracts, Elderberry extract exhibited the most significant negative impact. Comparatively, Oryza sativa L. demonstrated higher plant height, LAI, grain yield, biological yield, harvest index, chlorophyll content, grain protein content, and grain starch content when compared to Echinochloa crus-galli L. The results suggested that various extracts, particularly Nettle, along with 15 per thousand concentrations of Elderberry and Nettle extracts, hold potential for controlling Echinochloa crus-galli L. during the germination stage under field conditions.