Ornamental plants
Mahnaz Karimi; Fatemeh Salimi; Ali Pakdin Parizi
Abstract
Introduction Plant size control is one of the most important factors in the production of ornamental plants. Plant size can be limited by a variety of methods, including genetic control, environmental conditions, and the use of plant growth retardants. Lily (Lilium sp.) is one of the most important cut ...
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Introduction Plant size control is one of the most important factors in the production of ornamental plants. Plant size can be limited by a variety of methods, including genetic control, environmental conditions, and the use of plant growth retardants. Lily (Lilium sp.) is one of the most important cut flowers with different species and cultivars. Some lilies can grow up to one meter in height. Usually the appropriate height of the stem for pot use is 40-30 cm, which is achieved by using growth regulators. This study aimed to investigate the role of uniconazole and cycocel to control height, quantitative and qualitative characteristics of Lilium.Materials and Methods This study was carried out in a factorial experiment based on completely randomized design. Uniconazole (0, 5 and 10 mg L-1) and cycocel (0, 1000 and 1500 mg L-1) were the first factor and application methods of the above compounds (immersion application and foliar application) was the second factor. Disease-free bulbs (with a circumference of 15 cm) Lily (Longifiorum × Asistic cv. Eyeliner) was purchased from Saei Gol Company in Tehran. To apply the immersion treatment, the bulbs were immersed in a solution of cycocel (CCC) and uniconazole (UN) for 7 minutes before planting. Then they were planted in plastic pots. In foliar spraying treatments, the bulbs were first planted in pots and when the stem height reached 10 cm, they were sprayed with CCC and UN. Water was used for control treatment. Leaf number, plant height, total chlorophyll, total phenol, flower diameter, enzyme activity (PPO, GPX or CAT) and time of budding were measured. Analysis of variance was performed using SAS software and mean comparisons were analyzed by the least significant difference test.Results and Discussion The effect of growth retardant, the application method and their interaction was significant on stem height. The shortest plants were observed in foliage application of 10 mg L-1 UN which was not significantly different from the concentration of 10 mg L-1 UN in immersion method. The mechanism of growth retardants is to inhibit the biosynthesis of gibberellins. Therefore, they act as anti-gibberellins to reduce plant height. Uniconazole inhibits the biosynthesis of gibberellins by blocking kaurene oxidase, a P450 enzyme. The largest diameter of lily flowers was observed in immersion application of 1500 mg L-1 CCC however, there was no significant difference between flower diameter of mentioned treatment with immersion method of 1000 mg L-1 CCC and foliar application of 10 mg L-1 UN. Growth retardants increase endogenous cytokinin levels, resulting in increased cell division and improved flower growth and flower diameter. The effect of growth retardant on number of leaves was significant. The highest numbers of leaves were observed in 1000 and 1500 mg L-1 CCC. The effect of growth retardant, the application method and their interaction was significant on chlorophyll and phenol contents. The highest chlorophyll content was observed in immersion application of 10 mg L-1 UN. Growth retardants appear to increase chlorophyll content due to increased cytokines. The results of this study showed an increase in total phenol in plants treated with uniconazole 10 mg L-1. Growth retardants have been reported to increase phenol content by increasing plant resistance to environmental stresses. Catalase enzyme activity was significantly affected by growth retardant. The highest activity of CAT enzyme was related to CCC at 1500 mg L-1. The effect of growth retardant and their interaction was significant on GPX enzyme activity. The highest enzyme activity was obtained in plants sprayed with 1000 mg L-1 CCC. Growth retardants have been reported to increase enzyme activity, causing plant resistance to environmental stresses and delaying lipid peroxidation and membrane degradation.Conclusion Considering that one of the most important goals in the present study was the production of dwarf lilium, it can be said that uniconazole 10 mg L-1 (foliar application and immersion) had a significant effect in controlling stem height compared to other treatments. The effect of this treatment on other traits such as flower diameter, total chlorophyll and total phenol was also significant. The time of budding, leaf number and activity of CAT and GPX enzymes was better in cycocel treatment with a concentration of 1500 mg L-1. Therefore, the use of uniconazole can be recommended for the production of dwarf plants, considering that it works better in two important traits, including controlling stem height and increasing flower diameter. It is also suggested that since the cycocel treatment was effective in increasing enzymatic activity, the effect of this treatment on plant resistance to environmental stresses should be investigated.
Fatemeh Ghorbanalizade; Mahnaz Karimi; Kamran Ghasemi; Mehrnaz Hatami
Abstract
Introduction: Water hyacinth (Eichornia crassipes) is one of the world’s most prevalent invasive aquatic plants. Due to the environmental and economic concerns associated with the water hyacinth spread, control of this plant seems will be necessary. Composting is promising techniques for controlling ...
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Introduction: Water hyacinth (Eichornia crassipes) is one of the world’s most prevalent invasive aquatic plants. Due to the environmental and economic concerns associated with the water hyacinth spread, control of this plant seems will be necessary. Composting is promising techniques for controlling water hyacinth. Humic acid is the fraction of naturally occurring organic materials, which derive from the decomposition of plant and animal residues. Humic acid plays important roles in plants through stimulation of root growth and increase of water and nutrient uptake by plants. In this study, we evaluated the effect of water hyacinth compost and humic acid on the vegetative and reproductive characteristics of gerbera flowers
Materials and Methods: The present study was conducted as a factorial experiment in a completely randomized design with three replications. The first factor was water hyacinth compost (0, 25, 50, 75 and 100% v/v) and the second factor was humic acid (0, 250 and 500 mg L-1). The peat moss + perlite (2:1 v/v) was considered as a control treatment. To prepare water hyacinth compost, the water hyacinth was collected from a river in Sari, Mazandaran, Iran. Water hyacinth leaves were exposed to direct sunlight for eight hours to wither then chopped to fine pieces and eventually was spread on the surface. The thickness of leaves is five-centimeter. One centimeter thickness of animal manure was added on top of the water hyacinth leaves and then a layer of ash and lime respectively added. This step was repeated until the height of the layer reached to one meter, finally the top layer was covered with dry leaves of native trees and black polyethylene sheets. The mass was mixed up every 15 days to get a better result (uniform decomposition). Finally, after three months, the compost was prepared. Gerbera (cv. Artist) seedlings with uniform size (15 cm) were planted in plastic pots at different levels of compost. Humic acid was used once every ten days. The average day and night temperature in the greenhouse during the experiment was 17±2 and 23±2ºC, respectively, and the average greenhouse humidity was 65 to 75%. Flowering time, number of flowers, number of leaves, stem length, flower stem diameter, flower disk diameter, fresh and dry weight of shoots and roots, phenol content, total chlorophyll and carotenoids, concentrations of nitrogen, phosphorus, potassium and calcium in the leaves, ion leakage of petals and vase life were evaluated.
Result and Discussion: According to the results of the effect of compost, humic acid and their interaction on most of the studied characteristics were significant. The highest number of flowers with 117% increase compared to the control treatment was related to 50% compost + 500 mg L-1 humic acid. In this treatment, the time of flower emergence occurred 40 days earlier than the control. The highest chlorophyll content with 155.52% increase compared to control was observed in 25% compost + 500% humic acid. Mineral elements in the leaf of the Gerbera plant were significantly affected by growth media and humic acid. The highest nitrogen content was found in 50% compost + 500 mg L-1 humic acid (a 50% increase compared to control). The highest potassium content was observed in 50% compost + 250 mg L-1 humic acid. The highest concentrations of calcium were found in the leaves of plants grown in 50% compost + 500 mg L-1 humic acid. The highest vase life with a 71.67% increase compared to the control treatment was related to plants that were grown in 25% or 50% compost+ 500 mg L-1 humic acid. The lowest ion leakage was recorded in 50% compost + 500% humic acid with 56.79% decrease compared to the control. In the present study, most of the growth media and humic acid significantly affected most of the Gerbera plant parameters. The best results were obtained from 25% and 50% compost +250, 500 mg L-1 humic acid. Due to proper drainage, increased water retention, a pseudo hormonal compound such as auxin and increased absorption of elements, compost improve the chemical and physical structure of growing media. Also, high leaf nitrogen content was observed in most compost-containing substrates. This element plays a key role in vegetative growth. The concentration of nitrogen and phosphorus in compost is usually 5 to 11 times higher than soil which is gradually delivered to the plant and increases the growth and flowering of the plant. Humic acid plays important roles in plants through stimulation of root growth and increase of water and nutrient uptake by plants. In our study the application of humic acid at 250 and 500 mg L-1 significantly increased concentration of nitrogen, phosphorus, calcium and potassium as compared with control. It has also been reported that humic acid provides growth regulators to regulate and control hormone levels in plants and stimulates the production of plant enzymes and hormones, which ultimately increases the vegetative and reproductive growth of the plant.
Conclusion: The results of this study showed that water hyacinth compost with humic acid due to improving the root environment and increasing the absorption of nutrients, increased quantitative, qualitative and vase life characteristics of Gerbera in comparison with control (peat + perlite). 50% compost was introduced as the best treatment in combination with concentrations of 250 and 500 mg L-1 of humic acid.
