International Journal of Horticultural Science and Technology
Volume:11 Issue: 1, Winter 2024

Bacterial endophytes grow symbiotically inside of plants, and improve the growth of their hosts. We investigated the effects of inoculating Macroalgae bacterial endophytes, introduced formerly by our group, Bacillus aquimaris strain OD14, B. megaterium strain AM25, B. zhangzhouensis strain Tv91C, individually and in combination with each other on the reactive oxygen species (ROS) scavenging and antioxidant functions and growth characteristics in Mexican lime seedlings under salinity stress. To do so, Mexican lime (Citrus aurantifolia Swingle) seedlings were subjected to four salinity levels including 0, 2000, 4000 and 6000 µs/cm, in present/absent of the bacterial endophytes. The results indicated that salinity stress significantly reduced growth, chlorophyll and carotenoid content of the plants lacking endophytes. Combinatory applications with bacterial endophytes significantly improved the above-mentioned parameters under salinity stress. Lipid peroxidation level were significantly reduced in the plants that inoculated with bacterial endophytes. Salinity stress significantly increased activities of ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione reductase (GR), peroxidase (POD) and catalase (CAT), in salinity conditions. Overall, bacterial endophytes inoculation improved salinity tolerance and reduced the accumulation of ROS by increasing their scavenging via improving the redox state glutathione and promotion of antioxidant enzymes activity.

Adverse conditions during pre- and postharvest stages negatively affect the longevity and quality of horticultural crops, which should be considered in marketing management, especially for cut flowers. Methyl jasmonate, well known as a signaling molecule in plant defense responses, could be effective in improving the vase life of horticultural crops. The expression of Laccae gene, acting downstream of the ethylene signal transduction, induced by exogenous ethylene treatment. The PIP2 gene is one of the major groups of plasma membrane proteins that are link to aquaporin channels. This study investigated the effect of methyl jasmonate on postharvest quality and expression LAC and PIP2 genes of cut rose cv. ‘Red alert’. The results showed that methyl jasmonate improved cut roses vase life at all the examined concentrations, although it was most effective at 0.2 µl/l. Analysis of antioxidant enzymes indicated that the catalase activity at 0.2 µl/l and peroxidase activity under 0.2 and 0.3 µl/l methyl jasmonate concentrations were the highest, although both enzymes showed a decreasing trend during the vase life period. Proline levels significantly increased at 0.2 and 0.3 μl/L methyl jasmonate concentrations. Quantitative PCR analysis showed that all concentrations of methyl jasmonate significantly reduced the expression of PIP2 and LAC genes. The lowest expression level of PIP2 and LAC genes was under 0.2 and 0.3 µl/l methyl jasmonate, respectively. Based on our findings, the expression pattern of Laccase gene could be consider as a marker in evaluating postharvest characteristics of cut rose.

Citrus is among the low temperature (freezing) - susceptible plants. The performance of storage and breeding of horticultural crops is mainly dependent on the correlation among the traits. To determine the relationship between stress tolerance (LT50) and some important physiological traits and finding their direct and indirect effects, four commercial citrus cultivars of Japanese mandarin, Thomson orange, Ruby Star grapefruit and Lisbon lemon in three temperature levels (4, -4 and -8 °C) were studied at the Horticulture laboratory of Guilan University in 2021. Before treating and for adaptation of plant material to temperature decrease, the plants were moved to a temperate greenhouse and then to a +4 °C cool storage with 65±5 percent relative humidity. Illustrates the changes in LT50 as affected by changes in citrus lipid peroxidation, ion leakage and total flavonoid at +4 °C and –4 °C. According to the regression coefficient, a change of one unit in lipid peroxidation led to a 1.9238 and 5.9615 unit decrease in LT50 at +4 and –4 °C, for ion leakage led to 0.1661 and 0.3587 unit changes in LT50 at +4 and –4 °C and for total flavonoid led to a 0.0471 and 0.236 unit decrease in LT50 at +4 and –4 °C, respectively. According to the results of the present study which involved the selection of commercial citrus cultivars of Japanese mandarin, Thomson orange, Ruby Star grapefruit and Lisbon lemon in terms of stress tolerance and other traits, ...

Table grape is a non-climacteric fruit; however, it has a short shelf-life. Thus, some treatments that can prolong shelf-life and maintain the quality of table grape fruits are required. This study was carried out as a factorial based on a completely randomized design with two factors: the first factor was the storage period and the second factor was the combination of warm water treatments and gum arabic (GA). Fruits were stored at 5 °C and 80 % relative humidity in permanent darkness. On days 0, 20, 40, and 60, seven berries from each replicate were randomly sampled and analyzed for physicochemical and qualitative parameters. Although storage time had a negative effect on the measured traits of ‘Bidaneh Ghermez’ table grape fruits, this effect was lessened by the application of warm water treatments and GA coating, especially 45 °C+GA 5%. Compared to the uncoated controls, fruits that received 45 °C+GA 5%, showed more levels of vitamin C (30.43–160.00%), TSS/TA (total soluble solids/titratable acidity) (19.76–21.57%), anthocyanin (37.40–57.75%), antioxidant activity (7.35–36.40%), total phenol (12.01–24.49%), and sensory attributes (66.66–248.50%), but lower levels of weight loss (53.27–45.48%), H2O2 (hydrogen peroxide) (9.90–26.55%), and MDA (malondialdehyde) (8.84–27.92%) during storage. Therefore, the application of warm water treatments and GA coating, particularly 45 °C+GA 5%, in the shelf-life extension of fruits has revealed remarkable promising potential. The advantages of warm water and GA include their low cost.

Cumin (Cuminum cyminum L.) is a spicy, annual, outcross plant with medicinal properties from Apiaceae family, which is adapted to cultivation in arid and semi-arid regions of the world. To evaluate genetic parameters such as GCA and genetic distance based on molecular marker and important traits for parent selection among diverse genotypes, ISSR marker and polycross assay were conducted in College of Aburaihan, University of Tehran. Forty-nine half-sib families obtained from the polycross test were evaluated during two years under normal and drought stress conditions, and traits including 1000-seed weight, mechanized harvest height, and seed yield were evaluated. The statistical analysis showed the possibility of choosing elite parents due to the high genetic diversity among half-sib families. Estimation of narrow heritability more than 50 percent for studied traits revealed the contribution of both additive and non-additive effects in genetic control of evaluated traits. According to the general combining ability, drought tolerance indices, and genetic distance of 49 genotypes, the top 10 candidates were selected for the production of drought-tolerant synthetic seeds. In molecular point of view, the banding patterns obtained from ISSR markers showed significant genetic diversity among all genotypes and the proper distance of ten selected parents. The findings of this experiment provide a starting point for breeding program of cumin, which will continue by random mating of ten selected genotypes under controlled conditions to produce high-yield drought-tolerant synthetic variety.

Photosynthetic parameters and stem strength of Gerbera jamesonii ‘Bayadere’ plants were studied after foliar application of calcium chloride (0, 0.5, 1, and 1.5 g l-1) under natural light (NL), red light LEDs (R), blue light LEDs (B) and red + blue light LEDs (RB). Chlorophylls content was increased under LED lights and foliar application of calcium chloride. The maximal quantum yield of PSII efficiency (Fv/Fm) and performance index (PI) reached the lowest value under NL conditions. Photosynthesis rate, stomatal conductance, and transpiration rate (E) showed the highest values using RB lighting. Plants grown under the RB light and sprayed with calcium chloride exhibited the lowest leaf nitrate compared to NL conditions which resulted in the highest leaf nitrate content. The higher the nitrate content, the lower the stem strength is expected. However, calcium content of leaves showed the opposite trend. Sprays of 1.5 g l-1 calcium chloride under RB lighting significantly increased flower stem strength and reduced stem bending compared to non-treated plants. In summary, RB lighting along with foliar application of calcium chloride enhanced growth and flower stem firmness of studied cut gerbera.

Seed germination is a crucial stage in the life cycle of plants, as it determines their growth and reproduction success. Thus, to estimate the cardinal temperatures and the thermal time requirement for seed germination, as well as evaluate the effect of different temperature levels on the germination characteristics of tomatoes (Lycopersicon esculentum cv. Early CH), an experiment was conducted using a completely randomized design with four replications and seven determinate temperature levels (5, 10, 15, 20, 25, 30, and 35 degrees Celsius). To describe the relationship between germination rate and temperature and calculate the cardinal temperatures for tomato (cv. EARLY CH) seed germination, four types of regression models were used: segmented, dent-like, original beta, and modified beta. The highest germination percentage (81-86%) and vigor index (4.04-5.47 cm) were similarly obtained in the 20-30°C range. The highest germination rate (5/7 seeds per day) was observed at 25°C, and the lowest mean germination time (4.5-4.84 days) occurred in the 20-25°C range. Germination characteristics were significantly different when the temperature increased above 30°C. Based on the parameters for measuring regression models, the best model for estimating the cardinal temperature of this cultivar was segmented. In general, the study's results showed that the cardinal temperatures for seed germination were estimated using a superior regression model for minimum (0.5-3°C), optimal (25-26°C), and maximum (35.4-40°C) temperatures. Additionally, our thermal time model accurately predicted the seed germination process (R2=0.90), and the thermal time amount for 50% germination of this cultivar was estimated at 1848.29-degree hours.

In this study, we investigated important morphological traits of select populations of fiber Iranian hemp. The results of the analysis of variance showed significant diversity among the populations. Four of the eight genotypes showed large biomass suitable for use in the fiber industry. Kerman, Sirjan, Dezful, and Arak genotypes had the highest final height and the most prominent stem diameter. These populations also showed late flowering periods along with a short inflorescence length. Our classification study revealed that of the four high-fibrous candidates, three were classified in one group (Kerman, Sirjan, and Dezful), and the fourth one (Arak) was organized in the second group. The relationships among the traits showed a significant positive correlation between some characteristics, such as the final height, the footstalk diameter, and the number of days it takes for the first flower to appear. We also showed that there is a strong correlation between morphological traits and the geographical data of the genotypes. Our findings indicated that high elevation along with the low average annual temperature is suitable for the growth of medicinal cannabis, while warmer weather leads to taller plants with thicker stems andlate blooming periods, which are more relevant to be used in the fiber industry.

Olive shoots have a hard-rooting nature that causes significant problems associated with olive micro-propagation under in vitro conditions. Several factors may contribute to alleviating this problem, including zinc and its derivatives. The current research involved the application of zinc oxide nanoparticles and zinc sulfate on olive explants 'Caillette', 'Beldi', and 'Dezfoli' cultivars. FT-IR spectroscopy, UV-Vis spectroscopy, FESEM, EDS, and DLS techniques characterized the zinc oxide nanoparticles. Then, micro cuttings containing two buds were cultured on a half-strength MS medium containing 1.5 mg/L of BAP hormone and 1 mg/L of GA3 hormone. The treatments led to olive shoots, 3 cm in length, that were transferred to a half-strength MS medium containing 3 mg/L of IBA. The olive shoots were treated with two types of zinc compounds, including zinc sulfate (0.0, 2.43, and 4.86 mg/L) and zinc oxide nanoparticles (0.0, 2.43, 4.86, and 7.29 mg/L). The results showed that zinc oxide nanoparticles induced callus growth in response to all concentrations but prevented root growth. Alternatively, zinc sulfate at all concentrations induced root and callus growth, although to a smaller extent than nanoparticles. The 'Caillette' cultivar had the highest rooting percentage and heaviest fresh and dry root weight. The 'Beldi' cultivar had the lowest of these values. Several factors potentially contributed to these results, such as hormonal (auxin biosynthesis), biochemical (enzyme and other proteins), and molecular factors (bZIP TFs), which changed by zinc application. A complementary bioinformatics study was conducted as well.

In this study, we investigated the potential roles of the GolS and RfS gene families in grapevine drought tolerance. Through comprehensive bioinformatics analysis, we identified a set of putative genes associated with drought response in grapes. The analysis revealed the conservation of key functional domains and conserved motifs within the gene sequences, suggesting their potential involvement in stress adaptation. Additionally, we performed expression analysis of the identified genes under drought stress conditions, and the results indicated significant up-regulation of several genes, suggesting their potential importance in the grapevine's response to water scarcity. Furthermore, we explored the co-expression network of these genes and identified potential interactions and regulatory relationships, providing insights into the complex regulatory mechanisms underlying drought response in grapes. Our findings have implications for the genetic improvement of grape varieties, particularly in enhancing drought tolerance. By understanding the genetic basis of drought response, we can develop targeted strategies for crop improvement and breed grape varieties with enhanced resilience to water scarcity. In conclusion, this study sheds light on the potential roles of the GolS and RfS gene families in grapevine drought tolerance. The findings underscore the importance of these genes in the adaptation of grapes to water stress conditions. The knowledge gained from this study can be applied to guide future research and breeding efforts aimed at developing drought-tolerant grape varieties, ultimately contributing to the sustainability of grape production and the agricultural industry.