گیاهان زینتی
سال:1393 | دوره:4 | شماره:4 |تعداد مقالات:8

In vitro bud induction and shoot regeneration of Lantana camara L. was investigated using axillary nodal explants. Multiple shoot buds were induced on Murashige and Skoog (MS) media supplemented with 0, 2, 4 and 8 mg/l of 6-benzylaminopurine (BAP) or thidiazuron (TDZ) for proliferation and 0, 0.25 and 0.5 mg/l indole-3 butyric acid (IBA) for rooting. After 4 weeks, a maximum number of shoot buds was achieved on MS media containing 8 mg/l BAP and most buds were resulted in 8 mg/l TDZ. The results showed that the maximum length of shoots, internode length and weight were observed in MS media without any growth regulators. Suitable concentrations of cytokinins significantly increased RNA, DNA and protein synthesis and shoot induction. Difference in concentrations of BAP can be under the influence of genetic factors and experimental condition. Very low concentrations of TDZ stimulated the proliferation of lateral shoots in woody plants. Receptor molecules of TDZ had high affinity with this growth regulator. In this research, the highest number of roots was induced in MS media with 0.25 mg/l IBA. IBA is one of the strong PGRs in culture medium for stimulating and increasing the number of roots. IBA increases internal IAA, which is necessary for normal growth of root meristems and final development of roots. One of the effects of auxins is elongation of cells, but root cells need lower auxin for growth because auxin induces ethylene which is a root growth inhibitory.

In order to improve the vase life of alstroemeria cut flowers (Alstroemeria aurantiaca), an experiment was performed based on completely randomized design with 10 treatments including cycloheximide (50, 100 and 200 mg l-1), benzyladenine (50, 100 and 200 mg l-1), coconut juice (5, 10 and 20 %) and control (distilled water) in three replications. In this study, characteristics such as vase life, dry matter, increasing o Brix, the percentage of flower opening, chlorophyll a and b and ionic leakage were evaluated. The results showed that coconut juice at a concentration of 5% has the maximum vase life (17.39 days), although it has no significant difference with different levels of benzyladenine and 10 and 20% coconut juice treatments.10% coconut juice with 2.58 and 0.88 has the highest o Brix and flower opening index, respectively. Treatments of 50 mg l-1 benzyladenine, 5 and 10% coconut juice had the maximum impact on the amount of dry matter. The most successful treatments for reducing ionic leakage are two treatments of 5% coconut juice and 100 mg l-1 benzyladenine. All treatments cause maintenance of chlorophyll a and b compared to the control, and two treatments of 50 mg l-1 cycloheximide and 5% coconut juice had the highest content of chlorophyll a and b, respectively among treatments. According to the obtained results, using 5% coconut juice in the vase solution can effectively improve the vase life of alstroemeria cut flowers.

Leaf area information is required in various horticultural and physiological studies and it will be more useful if done via non-destructive methods. The objective of this study was to establish equations to estimate leaf area (LA) using length (L), width (W), fresh weight (FW), dry weight (DW), length ´ length (L2), width ´ width (W2), length ´ width (L´W), length+width (L+W), fresh weight ´ fresh weight (FW2) and dry weight ´ dry weight (DW2) of coneflower (Echinacea purpurea L.) leaves as a medicinal and landscape plant. An open field experiment was carried out to study relationship between leaf dimension and weight with leaf area of this plant. Observed leaf area was obtained by an automatic measuring device and leaf dimensions were measured by a ruler. A linear model employing L ´ W as an independent variables [LA=0.575 (L ´ W) - 0.934] resulted in the most accurate estimation (R2=0.874, RMSE=2.33) of coneflower leaf area. Validation of the regression model showed that the correlation between measured and simulated values by using this equation was quite acceptable.

The natural tragacanth gum, the sap of Astragalus gummifer, has been successfully used as a gelling agent in tissue culture media for in vitro shoot development and proliferation of miniature rose and carnation. Shoot development of nodal segments excised from greenhouse grown plants, was investigated on MS medium solidified with either 2.5, 3.0, 3.5 and 4.0% tragacanth or 0.8% agar as control. The media solidified with tragacanth were more transparent than the media solidified with agar. Viscosity of the tragacanth-gelled media was less than the agar-gelled media, and therefore, putting the explants on the media sometimes resulted in submersion of them into the media and some cases of development of hyperhydric shoots were observed. To increase the firmness of the media, the combinations of agar (0.2 and 0.3%) and tragacanth (2 and 3%) were used. The viscosity of the combinatory media was as good as the medium containing only 0.8% agar (control). Moreover, the explants productivity and growth obtained in these combinations were better than those recorded on the control medium. Being a plant product, biodegradable and environmental friendly, and 10 times cheaper than agar, tragacanth gum would definitely be useful for reducing costs, particularly in the plant tissue culture industry.

In order to improve the postharvest quality and the export ability of cut rose (Rosa hybrida L.) cvs. Happy Hour and Bordeaux, the effect of 1-methylcyclopropene (1-MCP) as an ethylene inhibitor, was investigated. 1-MCP was used at 0.3, 0.4, 0.5 and 0.6 g m-3 for 18 h at 8oC to simulate the transport of flowers.1-MCP treatment significantly prolonged the vase life and minimized the weight loss of both cultivars compared to the control, however the response of Happy Hour cultivar was higher than the Bordeaux cultivar.1-MCP treatment enhanced the relative water content (RWC) of flowers. The treatment of 1-MCP significantly retarded the degradation of chlorophyll and carbohydrate contents during vase life evaluation in both cultivars. The ethylene production was significantly decreased by applying 1-MCP treatment. The membrane stability index (MSI) was maintained while malondialdehyde (MDA) was decreased in response to 1-MCP treatment. The best treatments in this concern were 1-MCP at 0.4 and 0.5 g m-3 for Happy Hour and Bordeaux cultivars, respectively.1-MCP treatment was recommended to inhibit the negative effects of ethylene on rose cultivars tested.

In order to study the effect of foliar applications of micronutrients on yield, extraction oil production and chemical composition of pot marigold (Calendula officinalis), two experiments were conducted in the randomized complete block design with three replications in Shahrekord, Iran during two growing seasons 2014 and 2015. The objectives of this study were to determine the effects of foliar Fe2+, Cu2+, Zn2+, and Mn2+applications (0, 200 and 400 ppm) on flavonoid, phenols, carotenoids, extraction percentage, dry weight of the flower and the number of flowers of pot marigold. Results showed that foliar applications of Fe2+, Cu2+, Zn2+, and Mn2+ had significant effects on fresh and dry flower yield, number of flowers, extraction oil percentage and flavonoids, phenols, carotenoids of pot marigold plants, so that the highest dry weight of flowers (11.9 g per plant), number of flowers per plant (33.5), extraction oil percentage (1) and flavonoids (31.2 mg/ 100 g F.W.), phenols (56.2 mg/ 100 g F.W.) and carotenoids (0.8 mg/ 100 g F.W.) content were obtained from the application of a combination of Fe2+, Cu2+, Zn2+, and Mn2+ at 400 ppm concentration as compared to control in the second year. It seems that in climatic and edaphic conditions of Shahrekord, the best treatments for obtaining the highest extraction percentage and morphological characters of Calendula is 400 ppm of Fe, Zn, Cu and Mn.

Euonymus spp. (L.) are some of the most important ornamental plants. Fungal plant pathogens of ornamental plants are the most important factors causing damage. In this research two pathogenic fungal species were isolated from naturally infected Euonymus species and identified. In order to isolation of fungi from disease tissues, the obtained samples were cultured on potato dextrose agar medium. Isolates were cultured due to sporulation on water agar medium. Morphological characters of isolates were studied in order to identify the taxonomy. According to the results, isolates were belonged to Phoma sp. and Colletotricum gloeosporioides. Pathogenicity test of isolates was done in desiccators, and revealed the pathogenicity levels of these fungi and their ability to cause leaf blight on Euonymus spp. This reaction occurred as complete random design (CRD) with eight treatment and three replications. Based on the variance analysis, there was not any significant difference in the disease rating of studying fungi. But based on the sizes and types of the spots appeared on the Euonymus spp. and Horsfall-Barratt system, plants were more affected by the Phoma sp. compared with C. gloeosporioides., and its disease rating was higher and plants showed less tolerance.