Ornamental plants
M. Karimi; F. Salimi; A. 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.
Medicinal Plants
L. Vojodi Mehrabani; Y. Anvari Gheshlagh; A. Motallebiazar
Abstract
Introduction
NaCl Salinity is one of the major environmental stressors affecting agricultural production everywhere. Salinity impacts the plants by the osmotic stress, nutritional imbalance with plants cells and by reducing the nutrients absorption and reactive oxygen species over-generation, ...
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Introduction
NaCl Salinity is one of the major environmental stressors affecting agricultural production everywhere. Salinity impacts the plants by the osmotic stress, nutritional imbalance with plants cells and by reducing the nutrients absorption and reactive oxygen species over-generation, as well as by ionic competition for the absorption, translocation, distribution and ion toxicity inside plants. Under salinity stress, plants develop various physiological and biochemical mechanisms to overcome this conditions, like ion homeostasis and compartmentalization, ion uptake, biosynthesis of osmoprotectants, activation of antioxidant enzymeic (superoxide dismutase, catalase, ascorbate peroxidase and glutathione peroxidase) and nonenzymic compounds (proline) to overcome salinity stress. Optimum nutrition under stressful saline conditions is important to overcome the problem and to produce optimum yield. Pelargonium graveolens is a plant commonly used in food and pharmaceutical industries. Iran has favorable micro-climates for the Pelargonium graveolens, production, and since this plants is in common use with diverse industries, this experiments was conducted to study the effects of foliar spray with Se and nano Fe on growth and physiological traits Pelargonium graveolens under NaCl salinity depression
Materials and Methods
Two separate experiments were concluded to evaluate the effects of foliar application of selenium and nano-Iron (0, 1.5 and 3 mgL-1) on pelargonium under saline (0, 50 and 100 mM) conditions as factorial based on Completely Randomized Design. In the first experiment, the effects of magnetized Iron and in the second experiment, the effect of selenium were assayed on pelargonium growth and physiological traits (plant dry weight, enzymic activity, elemental content, essential oil percent and oil constituents) under salinity stress.
Results and Discussion
The results obtained from the first experiment showed that, the aerial parts dry weight, Na, Fe and H2O2 content, catalase activity and oil percent of Pelargonium graveolens were independently affected by the salinity and (1.5 and 3 mgL-1) Fe foliar treatment. At the first experiment the highest amount of K/Na ratio, flavonoid content, K content, malondialdehyde, proline and superoxide dismutase activity were influenced by salinity stress. The top amount amount of plant dry weight, Fe content, K/Na, Na and superoxide dismutase activity were recorded at control plants. The top amounts of Na, proline, malondialdehyde, H2O2 content were recorded at 100 mM salinity stress. control and 50 mM NaCl increased oil percent in plants. Foliar spray with 1.5 and 3 mgL-1 Fe increased catalase, yield, phenolic content and oil percent in plants. At the second experiment; aerial parts dry weight, proline and flavonoid content were influenced by salinity stress. Catalase activity, malondialdehyde, superoxide dismutase activity and H2O2 content were influenced by sole effects of salinity and Se foliar application. Under non saline condition, plant dry weight, superoxide dismutase activity, K content were increased in plant. With increasing salinity to 100 mM NaCl, proline, malondialdehyde and H2O2 content were increased. Se, Na content and K/Na ratio in the second experiment was influenced by the interaction effects of salinity and foliar spray. At the second experiment, the top amount of K/Na ratio were recorded at NaCl0 × 1.5 and 3 mgL-1 Se spray. The top amounts of Na were recorded at NaCl0 × no foliar application. The superoxide dismutase activity, malondialdehyde and K+ were responded to the individual effects of salinity and Se treatment. The highest amounts of total phenolic content was attained by (1.5 and 3 mgL-1) nano Fe and Se treatment in both experiment. With salinity of 50 and 100 mM, the flavonoids contend was increased at both experiments. Foliar spray with 1.5 and 3 mgL-1 Nano Fe and Se increased catalase activity in plants. 1.5 and 3 mgL-1 Se and nano Fe foliar application reduced H2O2 content in plant at both experiment. GC/MS analysis revealed that β-citronellol (12.5-20.5%) was the major constituent with control treatment Citronelly formate (10.75-25.2%) were the dominant constituents of oil control plants. Β-Thujone (12.61%), trans-Rose oxide (2.85- 9 %) and the highest amounts of Aromadendrene (5.42 %) only recorded at control plants. Salinity stress and foliar spray had negative effects on α-Pinene biosynthesis and the highest amounts of α-Pinene was recorded in control plants. The top amounts of Geranyl formate (0.7-7.8 %) was recorded at NaCl50 × 1.5 mgL-1 Fe spray. Y- muurolene (0.4 – 4.06 %) biosynthesis increased at NaCl50 × 1.5 mgL-1 Se.
Conclusion
Salinity stress involves changes in metabolic processes and various physiological traits, controlled by salinity stress severity. In total, salinity had negative effects on the growth and physiological responses of plants, however, foliar treatment with Se and Fe improved some physiological traits of Pelargonium graveolens.
