Journal of Ornamental Plants
Volume:13 Issue: 4, Autumn 2023

In recent years, as a result of environmental stress, a large number of pine trees in parks and forestry in Tehran and Alborz provinces have dried up, that has conditions provided for contamination by secondary pests such as pine bark beetles (Orthotomicus erosus). In one hundred pine growing locations, three trees were randomly selected in each location, and in these locations, the average percentage of trees canopy dryness (three trees), the percentage of soil area under the trees canopy and the number of irrigations during in growing season (spring and summer) were measured; and thus the soils were sampled from the root activity zone at two depths of 0-30 and 30-60 cm. The percentage of coarse particles (> 2 mm) was measured in the soil samples after being dried in the vicinity of air, pounded and passed through a 2 mm sieve. In each soil sample, soil texture (percentage of sand, silt and clay particles), soil pH, electrical conductivity (ECe), equivalent calcium carbonate (CCE), organic matter and available concentration of sodium, potassium and phosphorus elements were measured. At a depth of 30-60 cm (subsurface soil), a soil sample was taken with a cylinder in order to measure the bulk density and soil porosity. Regression analysis was carried out using three methods Enter, stepwise by backward and forward with 15 series of variables as input variables to estimate or predict the percentage of pine drying (dryness of tree canopy). In total, the forward stepwise regression model, with R2=0.757 and RMSE=15.02% error, the most suitable model is the most appropriate model for assessing the percentage of tree drying, with two variables, the percentage of subsurface sand of the soil (30-60 cm) and coarse material (> 2 mm) of soil surface depth (0-30 cm), a more suitable model was recognized.

In order to control the sunlight in the open air and greenhouses in Iran, shade nets are essential. Using shade nets can reduce the air temperature in the covered area. The selection of shade nets with the right color has been shown to have an important role in the growth of ornamental plants under similar conditions. In order to accomplish this objective, an experiment was conducted to examine the impact of shade netting in the shades of blue, white, and green (at a shade level of 50%) on the growth of Dieffenbachia amoena ornamental foliage plants. The basic design of the experiment consisted of randomized complete blocks. During the five-month economic growing period under greenhouse conditions, plant height, diameter, and chlorophyll index were measured every two weeks. At the end of growth, the leaf fresh and dry weight, stem fresh and dry weight, plant growth index, and leaf nutrients were measured. The results indicated that Dieffenbachia grown under blue shade nets had higher height, growth index, root dry weight, and iron than those grown under white and green shade nets. Since most Iranian greenhouses produce this ornamental plant under green shade nets, and consi-dering that these two colored shade nets have similar prices, it is recommended that Dieffenbachia be produced under blue shade nets.

Biochar is a sort of organic fertilizer derived from the pyrolysis of plant residuals and crop waste and is recommended for improving soil fertility and modifying saline soils. In this regard, the effect of biochar on moderating the effects of salinity stress on growth and some physiological traits Catharanthus roseus L. was explored in a factorial experiment based on a randomized complete block design with two treatments including salinity stress (0, 1000, 2000, and 3000 mg/kg NaCl) and biochar (0, 2, and 4%) in 3 replications, 36 plots, and 6 plants per plot. The study was conducted in pots in the spring of 2021. The results showed that salinity negatively influenced all studied morphological traits and relative water content (RWC) whereas biochar, especially at the rate of 2%, helped their preservation and improvement. With increasing the salinity level, the proline content and total soluble solids (TSS) increased versus the control. The highest level of proline (346.48 mmol/kg FW) and TSS (1.42°Brix) were recorded for NaCl3000 mg/kg × biochar0%. A decline was recorded in malondialdehyde (MDA) with the application of 2% biochar at all four NaCl levels, but biochar at the rate of 4% failed to alleviate salinity effects at the highest level of NaCl (3000 mg/kg) and this treatment exhibited the highest MDA level. The highest activities of peroxidase (POD) (1.56 IU/g FW/min) and ascorbate peroxidase (APX) (9.40 IU/g FW/min) were observed in the treatment of NaCl1000 mg/kg × biochar2%. With increasing the NaCl level (2000 and 3000 mg/kg), POD and APX activities decreased, which was accompanied by an increased accumulation of MDA. Based on the results, it can be concluded that by applying 2% biochar at the salinity level of 1000 or 2000 mg/kg, periwinkle plants with acceptable morphophysiological traits can be produced.

In recent years, the symptoms of viral diseases such as dwarfism, mosaic, discoloration, necrosis, and circular spots have been prevalent in ornamental plants in parks, gardens, and streets in North Khorasan Province. Tomato spotted wilt virus (TSWV), the type species of the genus Orthotospovirus, the family Tospoviridae, and the order Bunyavirales, is a tripartite negative/ambisense ssRNA virus. This virus is a major cause of the infection of ornamental plants in the world. In this study, to evaluate the percentage of infection to TSWV, in the early autumn of 2020, 350 samples of ornamental plants were collected based on the suspicious viral symptoms from parks, gardens, and streets of North Khorasan province (Bojnord and Shirvan cities) and were transported to the laboratory in cold conditions. In the laboratory, DAS-ELISA serological test was performed to evaluate the presence of virus in the suspected samples. Then, the infected samples identified by ELISA test were inoculated to the test plants of Chenopodium album L. (lamb's quarters), Vigna unguiculata L. (cowpea) and Datura stramonium L. (jimsonweed). After the appearance of symptoms, in order to verify the infection, they were tested again using DAS-ELISA. The molecular identification of the infected samples was done by Qiagene RNA extraction kit. Using specific primers in RT-PCR reaction, a fragment was amplified in the band of 276 bp. The results of DAS-ELISA and RT-PCR tests proved the presence of the virus on ornamental plants in North Khorasan province. In the mechanical inoculation of the virus, three above-mentioned plants showed the symptoms of the disease.

One of the most significant decorative and medicinal plants, the dog rose (Rosa canina L.), serves as the rootstock for the majority of ornamental roses, including hybrid roses. The quick growth with desirable traits and the creation of wholesome, disease-free plants are the major outcomes of in vitro rose propagation. So, in order to provide micropropagation instructions for this plant utilizing nodal explants, this research was carried out. Many factors including the type, concentration, and phase of culture medium, sampling season, type, and concentration of hormones were investigated in several experiments. Explant disinfection was significantly affected by the timing of immersion in different sodium hypochlorite concentrations as well as the explant sampling season. The explants harvested in the winter and treated with 1% sodium hypochlorite showed the lowest rate of infection and the best percentage of survival. The percent of explant establishment was affected by the culture medium used as well as the IBA and BAP concentrations employed; the highest percentage of explant establishment was found in the MS culture medium with 0.3 mg L-1 BAP and or 0.4 mg L-1 IBA. The solid MS culture medium with 0.5 mg L-1 BAP had a stronger impact on proliferation. The results of the root formation test proved that the highest percentage of rooting is obtained in the half-strength MS culture medium with 2 mg L-1 IBA. After adapting to the environment with more than 80% survival, the produced plants were finally moved to the greenhouse. Using these findings, Rosa canina can be quickly commercially propagated for use in breeding and conservation efforts.

Rose, the queen of ornamental plants, is used as a new food source that is rich in nutrients and biologically active compounds in modern cuisine. Despite the popularity of rose flowers in cooking, many rose cultivars and species have not yet been subjected to research on their edibility. So, the present study aimed to determine the nutrients, minerals, and antioxidant compounds of six rose cultivars (‘Hella’, ‘Crimson Siluetta’, ‘Rainbows End’, ‘Dolce Vita’, ‘Samurai’, and ‘Avalanche’) in an experiment based on completely randomized design with three replications. The cultivars were procured at the full-blooming stage at an authentic producer in Tehran province and were transferred to the laboratory in proper packages. The petals were used to determine the nutritional and antioxidant properties. The results showed that ‘Crimson Siluetta’ was the richest in dry matter (22.75%), total phenols (20.20 mg GAE/100 g FW), antioxidant capacity (85.83% DPPH), P (33.48 mg/100 g FW), and Mn (2.76 mg/100 g FW). The best cultivars in vitamin C and anthocyanin were ‘Crimson Siluetta’ and ‘Samurai’, which did not differ significantly from one another. The richest cultivars in total flavonoids, carotenoids, N, and protein were ‘Rainbows End’ and ‘Dolce Vita’. Also, ‘Dolce Vita’ had the highest vitamin A (0.39 µg/100 g FW) and S content (356 mg/100 g FW). The highest fibre, Fe, Zn, Cu, Ca, Mg, Ni, and B were recorded by ‘Hella’, the best cultivar in K, along with ‘Samurai’. All six cultivars were good sources of minerals, nutrients, and antioxidant compounds. Among them, ‘Hella’ was richer in fibre and minerals, ‘Crimson Siluetta’ was richer in antioxidant compounds, and ‘Dolce Vita’ and ‘Rainbows End’ were more affluent in vitamin A and carotenoids, so they are recommended in human food regime as they are good for their health.