Journal of Ornamental Plants
Volume:13 Issue: 3, Summer 2023

Orchids are universally popular due to the wide range of colors, sizes, shapes, and scents in their flowers. The demand for orchids as cut flowers and pot plants is increasing in the flower market. Seed germination of orchids is comparatively low in the wild as they typically require fungal symbionts during their germination. Micropropagation of orchids is a major approach to orchid conservation and commercial production. Cephalanthera rubra (L.) Rich., one of Iran’s endangered orchid species, has been cloned using leaf as explant, Murashige and Skoog (MS) as culture medium, and α-naphthalene acetic acid (NAA) and 2,4-dichlorophenoxyacetic acid (2,4-D) (both at the concentrations of 0, 0.1, 0.2, 0.3 and 0.4 mg L–1) as well 6-benzyladenine (BA) (at 0, 1, 2, 3 and 4 mg L–1) as plant growth regulators (PGRs). In order to initiate an axenic culture, the disinfection of leaf explants was performed with sodium hypochlorite and mercury chloride. The highest number of shoots (4.33) was obtained in medium enriched with 4 mg L–1 BA. Maximum stem length (4.73 cm), leaf number (5.33) and node number (2.86) was obtained in medium supplemented with 3 mg L–1 BA. The largest number of root (5) and the highest length of root (4.83 cm) was produced on medium augmented with 0.3 mg L–1 NAA. Rooted plantlets were transferred to pots filled with peat and perlite in 1:1 proportion and acclimatized to ambient greenhouse conditions with an average of 90% survival rate. This is the first report on the micropropagation of C. rubra (L.) Rich.

Rose is an important cut flower crop throughout the world in the floriculture industry. One of the most important problems of cut roses is their short post-harvest vase life, which imposes huge losses for cut plant production and trade in the market. This study aimed to investigate the effects of γ-aminobutyric acid (GABA) and calcium chloride (CaCl2) on vase life and the ACC synthase activity of cut rose cv. ‘Jumilia’ flowers. A factorial experiment based on a completely randomized design (CRD) with 12 treatments and 3 replications was carried out in a soilless culture greenhouse. The treatments included GABA in four concentrations (0, 20, 40, and 60 mM) and CaCl2 in three concentrations (0, 0.75, and 1.5% as foliar application). The combined application of GABA and CaCl2 significantly prolonged the vase life of the cut rose flowers compared to the control. The results showed that the highest and lowest vase life were obtained from the flowers treated with 20, 40, or 60 mM GABA and 0.75 % CaCl2 and the untreated flowers, by 19.1, 18.86, 18.74, and 13.85 days, respectively. The pre-harvest application of GABA and CaCl2 inhibited the ACC synthase activity. The highest and lowest ACC synthase activity were observed in plants treated with 40 mM GABA and 1.5 and 0.75% CaCl2 and the untreated flowers by 3.57, 3.96, and 8.18 nmol g-1 FW, respectively. The combined application of GABA and CaCl2 increased the Ca content by 100.95% compared to the control plants. The highest and lowest total chlorophyll contents in the leaves were related to the plants treated with 60 mM GABA and 0.75 and 1.5% CaCl2 and the untreated flowers by 8.4, 8.24, and 6.22 mg g-1 FW, respectively. The foliar application of GABA and CaCl2 significantly (P < 0.01) increased the polyamines (PAs) contents, such as putrescine (Put), spermidine (Spd), and spermine (Spm), in the petals of the treated rose flowers. So, the use of foliar application GABA 60 mM and CaCl2 1.5% is recommended due to the 38% increase in the vase life of cut rose flower.

The effects of naphthaleneacetic acid (NAA) (0, 15, 20 and 25 mg/l) were explored on the rooting of Cycas revoluta bulbs in a study based on a randomized complete block design with four replications. Based on the results, the NAA treatments significantly influenced root length, leaf fresh and dry weight, and chlorophyll. But, they did not affect root number, root fresh and dry weight, significantly. The longest roots were 9.43 and 9.63 cm produced by the bulbs treated with 25 and 20 mg/l NAA, respectively. The 25 and 20 mg/l  NAA were related to the highest root number of 3.57 and 3.23, respectively, the 25 mg/l  NAA was related to the highest mean root fresh weight of 4.9 g, the 25 mg/l  NAA was related to the highest root dry weight of 2.5 g, the 20 and 25 mg/l NAA were related to the highest leaf fresh weight of 6.04 and 6.54 g, respectively, the 25 and 20 mg/l NAA were related to the highest leaf dry weight of 4.07 and 3.11 g, respectively, and the 20 and 5 mg/l NAA were related to the highest chlorophyll content of 6.28 and 6.22 mg g-1 F.W., respectively. A significant relationship was observed between leaf dry weight and chlorophyll content at the P < 0.01 level (+0.78). But, there was no significant relationship between root dry weight and mean root length (+0.29). The relationship between chlorophyll content and mean root length was not significant either (+0.13). According to the results, increasing the hormone rate may even affect the plants adversely, injuring them. In general, it can be inferred from the results that NAA at the rate of 20 mg/l influenced the studied traits, thereby entailing the highest gene expression in C. revoluta.

The amount of internal anthocyanin in carnation cut flowers may be one of the factors affecting the vase life of colored carnations. Two experiments were conducted to examine the effect of changing the internal anthocyanin concentration in petals and the using of external sucrose on vase life of four cultivars of carnation cut flowers in this study. Four carnation cultivars were used including: white (White Liberty), yellow (Yellow Liberty), pink (Tabor), and red (Grand Slam). In the first experiment, the changes in internal anthocyanin of petals and its effect on vase life of the four cultivars were investigated. Different concentrations of external sucrose (0, 2 and 4%) on post-harvest traits of four mentioned cultivars were evaluated in the second experiment. The results of the first experiment showed that the possibility effectiveness of internal anthocyanin on vase life of carnation. Vase life of the cultivars without internal anthocyanin (white and yellow) was twice (14 days) as long as that of the red and pink cultivars containing anthocyanin (7 days). Results of the second experiment indicated that external sucrose improved the vase life traits. Moreover, the lowest vase life was observed in red cultivar (13.7 days) without the using of external sucrose and the highest vase life was found in the pink cultivar (18 days) treated with 4% external sucrose. In general, increasing in internal anthocyanin in the absence of external sucrose reduced vase life. Using of external sucrose increased the vase life of cultivars containing more anthocyanin.

Marigold (Calendula officinalis L.) is also known as one of the common edible flowers. In this study, the improvement of nutritional value and shelf life of marigolds under the covers of packaging and gaseous composition was investigated. Marigold flowers in plastic packages made of polyethylene, polyamide, and the combination of these two covers with gas composition (1: 5% O2 + 5% CO2; 2: 5% O2 + 10% CO2; 3: 5% O2 + 20% CO2) or without gas combination were placed along with the control (without packaging). These packages were transferred to the cold store at 4°C, and sampling was done to evaluate the desired traits on days 0, 5, 10, and 15. The results showed that with the increased storage time in all edible marigold flowers, the amount of weight loss, ion leakage, and decay increased, and the relative water content (RWC), total phenol, flavonoids, and carotenoids decreased. At the same time, using polyethylene and polyamide packaging treatment, along with gaseous composition, improved the visual and nutritional quality of flowers. Among all the treatments, the combination treatment of 5% O2 + 10% CO2 and polyethylene + polyamide coating had better effects in maintaining the quality and increasing the shelf life of the edible marigold flowers. As a result, considering the nutritional and medicinal value of the marigold flowers, this treatment can be used as an effective and safe method to increase the shelf life and maintain the appearance quality and biochemical compounds of this plant.

Thuja is one of the ornamental plants belonging to the conifers and Cupressales order. Coniferous trees are always important as creators of urban green spaces in terms of environmental values due to practical reasons and fast growth. In recent years, thuja wilt disease has caused irreparable damage to urban greenery, and its symptoms appear in the form of weakness and drying of the branches, which eventually causes the death of the tree. This research was conducted in order to investigate the causes of root and collar drying of thuja (Thuja plicata) in the west of Guilan province, during 2021-2022. In this study, samples were taken from the western regions of Guilan province. 40 samples were taken from the infected parts of the root and collar. After culturing the infected parts on the culture media, five fungal isolates were isolated in this study, the pathogenicity of this fungus was confirmed on potted thuja seedlings. Out of five isolates, two isolates showed wilting and rotting of the root and drying of the tips of the leaves with the same intensity of pathogenicity. These two isolates were similar in terms of their shape, and only one isolate was subjected to further laboratory work. Different cultures and molecular methods were used to identify this fungus. Based on the identification key and the molecular method, the disease-causing fungus F. oxysporum was identified.