Int. J. Plant Biol., Volume 13, Issue 3 (September 2022) – 15 articles

Biochemical and mineral peculiarities of plants inhabiting desert and semi-desert areas may provide important information about the mechanism of their adaptability and reveal the prospects of their utilization. Rheum tataricum L., known for its high tolerance to drought, salinity, and nutritional deficiency, is the least studied species of wild rhubarb. Using biochemical and ICP-MS analysis, the antioxidant status and mineral composition of R. tataricum were determined. Extremely high levels of antioxidant activity (148–155 mg GAE g⁻¹ d.w.), polyphenols (24.6–25.1 mg GAE g⁻¹ d.w.) and carotenoids (1.94 mg-eq β-carotene g⁻¹ d.w.) were revealed in roots, proline in leaves (71.1 ± 6.2 mg kg⁻¹ d.w.) and malic acid in stems (3.40 ± 0.50 mg g⁻¹ d.w.). Compared to garden rhubarb, R. tataricum demonstrated significant root–leaves translocation of Li, Se, Si, and Mo, known to participate in plant antioxidant defense. Under high levels of Ca, Na, Mg, Fe, Cr and Si in soil, R. tataricum demonstrated the ability to significantly increase the accumulation of these elements in roots, showing a hyperaccumulation ability for Sr. The first broad picture of R. tataricum biochemical and mineral characteristics in semi-desert habitat and its nutritional value indicate the prospects of R. tataricum utilization in plant breeding, medicine, and nutrition. Full article

The Bangladesh Rice Research Institute (BRRI) has released more than 100 inbred rice varieties. Still, an old mega variety BRRI dhan28 dominates the farmers’ fields during the dry winter (Boro season: November–June) season. This variety is very susceptible to different diseases and insects, causing lower yield performance than its potential. To replace this variety, current on-farm research was planned to evaluate the newly developed four superior rice varieties: BRRI dhan58, BRRI dhan63, BRRI dhan67, and BRRI dhan74 during Boro season in 2017 and 2018. The objective was to create data and popularize new varieties among farmers all over the country. We conducted 15 on-farm trials with farmers’ active participation at Senbag, Fulgazi, and Mirsarai Upazila of Noakhali, Feni, and Chattogram districts, respectively, in Bangladesh. The results demonstrate that BRRI dhan74 produced the highest grain yield among the tested varieties, followed by BRRI dhan67, BRRI dhan63, and BRRI dhan58, while BRRI dhan28 produced the lowest. However, BRRI dhan67 obtained the highest preference scores from the farmers and extension personnel due to its medium and slender grains, shorter growth duration, resistance to lodging, less disease, and less insect invasion. Moreover, stability indices for yield revealed that BRRI dhan67 was the most stable, adaptive, and appropriate variety, followed by BRRI dhan74, across the locations. Farmers showed keen interest to grow BRRI dhan67 by themselves instead of BRRI dhan28 all over the study locations. The neighboring farmers also expressed their curiosity about cultivating BRRI dhan67 over BRRI dhan28 by collecting seeds from the participating farmers. Thus, BRRI dhan67 could be a perfect replacement for BRRI dhan28. However, conducting participatory varietal evaluation trials across the agroecological zones of the country is recommended to validate the results of this study. Full article

Root-synthesized cytokinins regulate the growth, development, and stress responses of aboveground tissues and follow the transport route via xylem tissue. Arabidopsis ATP-binding cassette (ABC) transporter G family member 14 (AtABCG14) is involved in the xylem loading of root-synthesized cytokinins. However, the phloem unloading of root-synthesized cytokinin and shoot distribution have remained elusive. The recent study by Zhao et al., (2021) proved that the AtABCG14 protein mediates the phloem unloading of cytokinins through the apoplastic pathway indicating the AtABCG14 is a master regulator of shoot cytokinin distribution. Full article

This study investigated the effects of genotype, location, and planting season on the proximate composition and metabolizable energy of advanced maize hybrids. Twenty-five hybrid maize and a local variety as control were harvested from five locations 100 days after planting for two seasons. The maize samples were sorted, cleaned, and pulverized using a laboratory mill and were analyzed for nutritional composition and metabolizable energy (ME) using standard laboratory methods. Moisture content, ash, fat, and protein had mean ± SD of 8.97 ± 0.40%, 1.48 ± 0.05%, 4.31 ± 0.19, and 8.88 ± 0.18%, respectively. ME had a mean ± SD of 379.77 ± 2.17 kJ, and total carbohydrates had values ranging from 74.68 and 77.20%, with an average of 76.68%. Results showed that most of the variations expressed in the proximate compositions of the maize hybrids were not significantly (p > 0.05) dependent on the genotypes. In contrast, locations significantly affected the maize hybrids’ proximate composition and metabolizable energy (p < 0.001). In addition, there was no significant effect (p > 0.05) of location by genotype interaction on the proximate composition and ME of the maize samples. The planting season also exhibited a significant (p < 0.001) difference for all the proximate parameters. Fourteen out of the twenty-five maize hybrids were similar to the local variety in terms of proximate composition and metabolizable energy. Therefore, they could be recommended for advancement in the breeding stages for release for household and industrial uses. Full article

The present investigation was undertaken to standardize the media and the anti-browning regime in order to minimize the phenolic browning of an in vitro culture of Persian walnut cv. Sulaiman. The experiments involved two types of explants, forced and unforced shoot tips, two types of media, Driver and Kuniyuki Walnut (DKW) medium andMurashige and Skooģs (MS) medium, and three types of anti-browning agents, namely, Polyvinylpyrrolidone, ascorbic acid and activated charcoal at 150, 350 and 550 mg/L each. The investigation was replicated thrice under a completely randomized design. Forced shoot tips of cv. Sulaiman on DKW medium showed the best performance in terms of least browning (13.6 ± 10.5%) and highest survival percentage of explants (74.5 ± 2.4%) when treated with ascorbic acid at 550 mg/L. However, unforced shoot tips in MS medium did not perform well and manifested maximum browning (52.9 ± 5.2%). Based on the results, we conclude that incorporation of ascorbic acid in the DKW medium significantly reduced the media and explant browning, thus, it could set the basis of successful in vitro-propagation of walnuts. Full article

The chemical composition of the essential oils of two plants (Tagetes minuta L. and Lavandula coronopifolia L.) harvested from the Day region (in the north of Djibouti) is the subject of this study. The extraction of essential oils was carried out by hydrodistillation, and the average yield was obtained at a rate of approximately 0.25% for Tagetes minuta L. and 0.42% for Lavandula coronopifolia L. The analyses of these essential oils by gas chromatography coupled with mass spectrometry identified 13 compounds in the essential oil of Tagetes minuta L., including dihydrotagetone (20.8%), artemisia (17.9%), (Z)-tagetenone (12.4%), (-)-spathulenol (11.0%) and estragole (9.5%), were obtained as majority compounds, with a percentage of 71.6%. The essential oil of Lavandula coronopifolia L. is characterized by the presence of 42 compounds, including cis-caryophyllene (18.9%), dehydronerolidol (12.8%), isolongifolanone (11.2%), caryophyllene oxide (8.2%), 10-epi-β-eudesmol (7.7%) and humulene (5.1%), were obtained as the majority chemical constituents, with a percentage of 63.9%. The antimicrobial activities of the essential oils at concentrations of 5% were measured against 12 bacterial strains (Gram positive: Staphylococcus aureus (ATCC 29213), Enterococcus faecalis (ATCC 29212), Streptococcus agalactiae (ATCC 27956), Staphylococcus epidermidis and Corynebacterium sp.; Gram Negative: Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 700603), Acinetobacter baumannii (ATCC 19606), Shigella sonnei (ATCC 9290), Salmonella enterica sv. Typhimurium (ATCC 13311) and Enterobacter cloacae), and the results of in vitro experiments showed inhibitory effects against most strains tested except Staphylococcus aureus, Enterococcus faecalis and Streptococcus agalactiae. Additionally, both oils were tested for their ability to selectively kill 13 human cancer cells (K562, A549, HCT116, PC3, U87-MG, MIA-Paca2, HEK293, NCI-N87, RT4, U2OS, A2780, MRC-5 and JIMT-T1), and the results obtained, according to the values of IC₅₀, show the significant activity of two essential oils, particularly on the HCT116 and A2780 lines, which present values between 0.25 µg/mL and 0.45 µg/mL, respectively. Full article

Lemongrass (Cymbopogon citratus) essential oil (EO) is a major source of bioactive compounds (BC) with anticancer activity such as α-citral, limonene, geraniol, geranyl acetate, and β-caryophyllene. Comparative studies about cytokinin effects on BC profiles in lemongrass are missing. Here, we evaluated four cytokinins (2iP, tZ, BAP, and KIN) in two different osmotic media, MS-N (3% sucrose, 3 g L⁻¹ Gelrite™) and MS-S (5% sucrose, 5 g L⁻¹ Gelrite™). It results in a higher multiplication rate in BAP containing medium compared to tZ, KIN, and 2iP (p ≤ 0.05). While shoots grown on MS-N/BAP, tZ, and KIN exhibited a highly branching morphology, MS-N/2iP produced a less branching architecture. BC profile analysis of established plants in pots revealed that their maxima production depends on the in vitro shoot growth conditions: i.e., highest content (80%) of α-citral in plants that were cultured in MS-S/BAP (p ≤ 0.05), limonene (41%) in MS-N/2iP, or geranyl acetate (25.79%) in MS-S/2iP. These results indicate that it is possible to increase or address the production of BC in lemongrass by manipulating the cytokinin type and osmotic pressure in culture media. The culture protocol described here is currently successfully applied for somatic embryogenesis induction and genetic transformation in lemongrass. Full article

Microorganisms represent a viable option for the control of phytopathogens. From the surface of healthy mangoes, different bacteria were isolated. For all isolated bacterial strains, we determined their antimicrobial activity against a fungal strain that caused anthracnose in mangoes and against Alternaria alternata, both in the culture medium and directly on mangoes. The bacterial strains with the highest antifungal activity were identified by sequencing the 16s rRNA gene. Two species of Serratia were identified: marcescens and nematodiphila. Finally, the chitinolytic, glucanolytic, and cellulolytic activity and prodigiosin production of bacteria with antifungal activity was determined. Five fungal strains were isolated from mangoes with anthracnose. Only one strain was responsible for anthracnose in mangoes. This fungal strain was identified as Colletotrichum siamense. Against C. siamense and A. alternata in vitro and in mango selected strains of Serratia showed antifungal activity. Finally, the Serratia strains produced chitinases, glucanases, cellulases and prodigiosin, and the two S. marcescens strains did not produce hemolysins. The three Serratia strains isolated in this study can potentially be used in the biological control of anthracnose caused by C. siamense and A. alternata on mango. Full article

Kaffir lime is leaf-oriented minor citrus that required extra attention to study. This study aimed to (i) comparatively analyze the young and mature leaf morpho-ecophysiological characters; and (ii) perform a correlation analysis for revealing the relationship among the physiological characters. Plants were ten one-year-old kaffir lime trees cultured under full sun condition. Leaf size was measured by using a specific allometric model. The Li-6400XT portable photosynthesis system was used to observe the leaf ecophysiological characters. The statistical analysis revealed significant differences in leaf size and physiology as the effect of leaf age. A significant size enlargement in mature leaves was noticed, especially in terms of leaf length, area, and weight, of about 77%, 177%, and 196%, respectively. Young leaves experienced a significant improvement in photosynthetic rate and actual water use efficiency for about 39% and 53%, respectively. Additionally, a strong, significant, and positive correlation between leaf chlorophyll, carotenoid content, and photosynthetic rate was found in the present study. Further studies using a multi-omics approach may enrich the science between kaffir lime leaf maturation as the basis of agricultural modification practice. Full article

The use of plant growth-promoting rhizobacteria (PGPR) with biochar is apprised to be a promising bio-fertilizer for improving the soil fertility and plant growth and development. The current study aimed to identify a potential plant growth-promoting rhizobacterium alongside biochar to improve sesame seedling productivity. Our results revealed that among the nine isolates, SIR01, SIR03, and SIR07 significantly improved the growth and biomass of sesame and Waito-C rice seedlings. The increase in growth of Waito-C rice seedlings through isolate SIR01, SIR03, and SIR07, suggests their ability to produce phytohormones such as GA4, GA9, GA24, and GA34. Furthermore, the application of isolate SIR03 and biochar together revealed a synergistic increase in sesame seedling growth and biomass (fresh and dry weight) compared with their individual applications. This may be explained by enhancement of photosynthetic rate, chlorophyll fluorescence, stomatal conductance, and transpiration rate by the combined SIR03 and biochar treatment. This suggests that co-inoculation with SIR03 alongside the application of biochar can be considered an eco-friendly, low-cost bio-fertilizer to potentially improve sesame seedling growth and development. Full article

The mulberry tree (Morus alba) is a perennial and fast-growing tree distributed worldwide under different climatic conditions. Most of the world’s silk production (>90%) is facilitated by the feeding of silkworm larvae on the leaves of mulberry (Morus alba L.) varieties. Therefore, exploration of the protocol for improving the propagation efficiency and increasing the reproductive capacity of M. alba varieties could be of great significance. This study aimed to determine the effect of four concentrations (0, 100, 200 and 400 mg L⁻¹) each of naphthaleneacetic acid (NAA), indole-3-butyric acid (IBA), and zinc sulfate (0, 100 and 200 mg L⁻¹), supplied separately or combined, on the rooting and growth of mulberry cuttings. M. alba cuttings were immersed for 5 s in each solution using the quick-dip method and subsequently, the cuttings were dried and planted in plastic pots and maintained in a greenhouse for 60 days. The number of leaves (NL), longest root size (LRS), longest stem size (LSS), number of rooted cuttings (NRC), number of stems per tree (NSP), rooting percentage (RP), wet root weight (WRW), dry root weight (DRW), wet stem weight (WSW), dry stem weight (DSW), wet leaf weight (WLW) and dry leaf weight (DLW) were evaluated. The results obtained showed an increase in all growth parameters of the mulberry cuttings. Treatments of hormones (IBA and NAA) and Zn sulfate were effective on LSS, LRS and WSW. The highest values of LSS were obtained for the treatments T5, T6, T14, T15, T16 and T18. Moreover, T5, T12 and T10 showed the highest values of LRS. The highest value of WSW was observed for T18, T5, T14, T15 and T16. The highest values of WLW and DLW were observed in T20 and T14. Dry stem weight (DSW) was high in T18 and T14. The application of NAA (at 200 mg L⁻¹), IBA (200 and 400 mg L⁻¹) and Zn sulfate (200 and 400 mg L⁻¹), either alone or in double combination, can be a suitable and reliable method for mulberry propagation. Full article

Intensive agricultural management practices (i.e., the burning of pruning residues, the absence of organic amendments) lead to a reduction in organic matter and nutrients in the soil resulting in agroecosystem vulnerability. Implementing a cover crop would provide soil organic matter while increasing nutrition levels in the soil. A mixture of cover crop trial in sandy loam soils under Mediterranean climatic conditions was conducted in a rainfed olive grove in Western Crete. In this study, the dry biomass, macro- and micronutrition, and carbon status of the seeded cover crops (legume and grass) were compared to natural plants in an olive grove. Seeded cover crops were conducted in two sustainable management systems (cover crops solely, and a combination of compost, pruning residues, and cover crops); natural plants were in a conventional system involving soil tillage. In combination with conservation tillage practices, the addition of carbon inputs may improve soil fertility. Results indicate that the dry biomass production and C content of cover crops under sustainable management systems was significantly higher than that of the control. The higher dry biomass production and C content found in cover crops compared to the natural vegetation indicates not only that this type of management provides enhanced carbon storage, but can also potentially lead to a future increase in soil organic matter through decomposition. Higher dry biomass is important in the context of carbon sequestration, and cover crops facilitated carbon storage in this study. In addition, this study suggests that sustainable agricultural management practices would provide significant benefits in terms of nutrient retention and CO₂ fixation, thus improving ecosystems in Mediterranean countries. Full article

The paper presents the results on resistance of Aesculus hippocastanum Linnaeus, 1753 trees to Cameraria ohridella Deschka & Dimić, 1986 (Lepidoptera, Gracillariidae) impact under conditions of a modern urban environment on the example of Dnipro city as the largest industrial city in Ukraine. Field experiments were conducted in all park areas of the city, which allowed covering the full gradient of the existing urban environment and considered the different degrees of the tree settlement by the invasive insect species. The research of the impact of C. ohridella caterpillars’ vital activity on the photosynthetic apparatus state was carried out by applying a chlorophyll fluorescence induction technique. Diagnosis of photosynthetic dysfunction of fresh Ae. hippocastanum leaves was conducted using a portable “Floratest” fluorometer manufactured in Ukraine. Interpretation of the obtained Kautsky curves showed that significant changes in their critical parameters associated with the degree of leaf damage by C. ohridella caterpillars were not detected. The influence of tree growth site conditions on the following 4 main indicators of chlorophyll fluorescence induction was established: the initial value of fluorescence induction after irradiation; the value of “plateau” fluorescence induction; the maximum value of fluorescence induction; the stationary value of fluorescence induction after light adaptation of the plant leaf. It was found that the efficiency coefficients of photochemical processes in Ae. hippocastanum trees growing in low terrain levels differed significantly, which can probably be interpreted as their response to the specific characteristics of the urban environment. Full article

Bacillus velezensis has a broad application in the agricultural and industrial sectors for its biocontrol properties and its potential active secondary metabolites. The defined phenotypic characteristics of a strain vary according to its ecosystem. We report the complete genomic analysis of B. velezensis KS04AU compared to four strains of B. velezensis (SRCM102752, ONU-553, FZB42, and JS25R) and two closely related Bacillus amyloliquefaciens (LL3 and IT-45). A total of 4771 protein coding genes comprises the KS04AU genome, in comparison with 3334 genes core genes found in the six other strains and the remaining 1437 shell genes. Average nucleotide identity of the target strain to the six other strains showed 99.65% to B. velezensis ONU-553, sharing 60 orthologous genes. Secondary metabolite gene cluster analysis of all strains showed that KS04AU has a mersacidin cluster gene, which is absent in the genome of the other strains. PHASTER analysis also showed KS04AU harboring two phages (Aeribacllus AP45 NC_048651 and Paenibacillus_Tripp NC_028930), which were also unique in comparison with the other strains. Analysis on anti-microbial resistance genes showed no difference in the genome of KS04AU to any of the other genomes, with the exception of B. amyloliquefaciens IT-45 which had one unique small multidrug-resistance antibiotic efflux-pump gene (qacJ). The CRISPR-Cas systems in the strains were also compared showing one CRISPR gene found only in KS04AU. Hydrolytic activity, antagonistic activity against phytopathogens (Fusarium oxysporum, Fusarium graminearum, Alternaria alternata and Pseudomonas syringae) and biocontrol against tomato foot and root rot experiments were carried out. B. velezensis KS04AU inhibits the growth of all phytopathogens tested, produces hydrolytic activity, and reduces Fusarium oxysporum f.sp. radicis-lycopersici (Forl) ZUM2407 lesions up to 46.02 ± 0.12%. The obtained results confirm B. velezensis KS04AU as a potential biocontrol strain for plant protection. Full article

Currently, crop physiological responses to waterlogging are considered only in a few crop models and in a limited way. Here, we examine the process bases of seven contemporary models developed to model crop growth in waterlogged conditions. The representation of plant recovery in these models is over-simplified, while plant adaptation or phenotypic plasticity due to waterlogging is often not considered. Aeration stress conceptualisation varies from the use of simple multipliers in equations describing transpiration and biomass to complex linkages of aeration-deficit factors with root growth, transpiration and nitrogen fixation. We recommend further studies investigating more holistic impacts and multiple stresses caused by plant behaviours driven by soils and climate. A sensitivity analysis using one model (a developer version of APSIM) with default parameters showed that waterlogging has the greatest impact on photosynthesis, followed by phenology and leaf expansion, suggesting a need for improved equations linking waterlogging to carbon assimilation. Future studies should compare the ability of multiple models to simulate real and in situ effects of waterlogging stress on crop growth using consistent experimental data for initialisation, calibration and validation. We conclude that future experimental and modelling studies must focus on improving the extent to which soil porosity, texture, organic carbon and nitrogen and plant-available water affect waterlogging stress, physiological plasticity and the ensuing temporal impacts on phenology, growth and yield. Full article