Ornamental plants
Behzad Kaviani; Naser Negahdar
Abstract
IntroductionPoinsettia (Euphorbia pulcherrima) from the family Euphorbiaceae is used as potted and cut flower and has great importance in floriculture industry. Appropriate application of nutrients and plant growth regulators has an important role in increasing the quantity and quality of crops. The ...
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IntroductionPoinsettia (Euphorbia pulcherrima) from the family Euphorbiaceae is used as potted and cut flower and has great importance in floriculture industry. Appropriate application of nutrients and plant growth regulators has an important role in increasing the quantity and quality of crops. The successful application of various nanoplatforms in medicine under in vitro conditions has generated some interest in agro-nanotechnology. This technology holds the promise of controlled release of agrochemicals and site-specific targeted delivery to improve efficient nutrient utilization and enhanced plant growth. Nanoencapsulation shows the benefit of more efficient use and safer handling of pesticides with less exposure to the environment. Thus, nanofertilizers can be substituted for conventional fertilizers. The role of iron in the activity of some enzymes such as catalase, peroxidase and cytochrome oxidase has been demonstrated. Iron is present as a cofactor in the structure of many enzymes. The results of some studies showed that in the absence of micro-nutrients elements, the activity of some antioxidant enzymes decreased, which resulted in increased sensitivity of plants to environmental stresses. The use of nano-iron fertilizer is an appropriate solution to remove this problem. Some growth retardants such as cycocel, paclobutrazol, bayleton and daminozide reduced the plant growth. Growth reduction in some ornamental plants enhances their overall quality and marketing. Cycocel is one of the most important growth retardants which inhibits gibberellin biosynthesis and activity in plant. Today, a range of artificially made growth-reducing compounds are used in the floriculture industry. The effect of plant growth retardants, depends on the time and method of application, concentration, species and varieties type, type of target organ and environmental and physiological conditions. Plant growth retardants reduce the division and elongation of stem cells. These compounds also reduce stem length and growth by having a negative effect on gibberellin structure. Therefore, the present study investigated the effect of different levels of nano-iron fertilizer and different concentrations of cycocel on growth and development of poinsettia (Euphorbia pulcherrima Willd.). Materials and Methods These experiments were carried out based on a randomized completely block design in three replications to evaluate the effect of various levels of nano iron chelated fertilizer and cycocel on growth parameters of Euphorbia pulcherrima. Cuttings with a height of 15 to 20 cm, each with 3 nodes, were prepared from the mother plant of poinsettia. Cuttings were placed in water within 24 hours for exudation of latex. Then, cuttings were planted in perlite for rooting. After rooting (60-65 days), cuttings were transferred into substrates including cocopeat, municipal compost and soil in ratio of 1:1:1. Poinsettia cuttings were grown in pots. Treatments include nano-iron fertilizer (0, 0.9, 1.8, 3.6 and 4.5 g.l–1) and cycocel (0, 500, 1000, 1500 and 3000 mg.l–1). Application of EDTA-based nano-iron chelate as foliar spray was performed on plants at the beginning of the experiment and 30 days later, as well as the use of cycocel 30 days after the start of the experiment as foliar spray. Stem height, internode length, node number, root length, root number, root volume, leaf number, leaf surface, leaf total chlorophyll content, iron content in leaf and the number and longevity of bracts were evaluated. Results and Discussion Results showed that the lowest plant height and the highest leaf number, root length, root volume, the number and longevity of bracts were obtained in treatments of 1.8 g.l–1 nano-iron chelate without or with the concentration of 1000 mg.l–1 cycocel. In some traits such as root volume and chlorophyll content, the minimum amount was calculated in the maximum of nano-iron chelate and cycocel concentrations. Suitable root characters were severely reduced through the use of 3000 mg.l–1 cycocel. Overall, the most suitable treatment, especially for reduction of stem height and enhancing some vegetative traits (such as leaf number) and flowering (such as bract longevity) was 1.8 g.l–1 nano-iron chelate along with 1000 mg.l–1 cycocel. Research has demonstrated that cycocel application reduces plant height in various species, including ornamental plants, as confirmed by this study. Furthermore, this study reveals a novel effect of cycocel: it alters the weight of both aerial and underground plant parts, alongside influencing leaf iron and chlorophyll content. Notably, plant growth retardants like cycocel are known to increase cytokinin content, which in turn can lead to elevated leaf chlorophyll levels.
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.
Pomology
Mostafa Alizadeh; Mehrab Yadegari; Gholamhossein Davarynejad; Seyyed Hossein Nemati
Abstract
Introduction Pear (Pyrus communis L.) is one of the major fruit trees in the world which grown in temperate zones. In pear breeding program the bigger fruit size with better quality as well as market acceptability are usually in interest. In fruit trees, the size and yield of fruit are closely depended ...
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Introduction Pear (Pyrus communis L.) is one of the major fruit trees in the world which grown in temperate zones. In pear breeding program the bigger fruit size with better quality as well as market acceptability are usually in interest. In fruit trees, the size and yield of fruit are closely depended on cultivar and rootstocks. The variations of nutrient uptake, water use efficiency, photosynthesis performance, and resistance to biotic and abiotic stresses have been reported among different combinations of cultivars and rootstocks. Therefore there is a close relation between cultivar and rootstock with yield and quality of produced fruits. In recent years the semi dwarf clonal rootstocks of pear including OH×F, Pyro and FOX series have received more attention. However the performance of these rootstocks varies depending on scion cultivar, climatic condition, soil type, and planting system. Materials and Methods This experiment was conducted to assay the growth characters and fruit yield of Dargazi and Louise Bonne (Beyrouti) grafted onto PyroDwarf and OH×F69 rootstocks at the Orchard of Astan Quds Razavi, Mashhad, Iran (36°17' N, 59°36' E; altitude. 985 m) during 2018-2019 and 2019-2020. The experiment in both consecutive years was done as a factorial in the base of randomized complete blocks with four replications. The studied cultivars were grafted onto PyroDwarf and OH×F69 rootstocks in late spring 2016. The used water was pit water with 695 µSiemens/cm EC and pH 7.17. Evaluation of plant growth was carried out at the end of the season. The studied traits were included tree height, internode length, vertical and horizontal growth of shoots in the current season, trunk diameter above, below and in the grafting line, leaf area, shoots angel and the number of sucker per tree. These characters were assayed in three trees per each replication. The trunk diameter at the below and above the grafting line was calculated according to trunk circumference that was measured at 10 cm above and below the grafting point. Leaf area in each tree was assayed with area measuring device. Flowering characteristics (start blooming and end of bloom) were determined. Fruit ripening season was also recorded. Yield of trees was assayed by weighting of produced fruits in each tree with a digital scale. The combined analysis of obtain data was conducted by SPSS and differences among means of data were determined by Duncan's multiple ranges test at P≤0.05. The reported data was the mean of two studied years.Results and Discussion The obtained results showed the variation in growth and bearing properties of different combinations of Beyrouti and Dargazi cultivars with PyroDwarf and OH×F69 rootstocks throughout the studied years. The analysis variance showed the significant effect of year, cultivar and rootstock on growth characteristics of pear tree. Also the interaction effects of cultivar and rootstock were significant on tree growth response with exception of internode length. The most studied parameters showed a significant increasing during the two consecutive years. During the studied years the height and width of pear trees were increased up to 10.44 and 14.54%, respectively and the trunk diameter was increased by 10%. According to obtained results the growth of Dargazi cultivar was higher than the Beyrouti cultivar. The effect of OH×F69 rootstock on growth increasing of studied cultivars was prominent than PyroDwarf regards to tree height, shoot length and internode length. However the highest trunk diameter and leaf area density of both cultivars was found in PyroDwarf rootstock. Although the time of blooming and fruit ripening of each cultivar was not influenced by the rootstock but the bearing characters were varied between the Dargazi and Beyrouti cultivars. The highest yield of pear fruit was obtained in Dargazi cultivar and grafting onto PyroDwarf rootstock significantly enhanced the fruit yield in both cultivars.Conclusion The rootstocks have a key role on growth and yield of pear trees as well as their responses to abiotic stress. Rootstocks through influencing the physiological characteristics of grafted scions regulate the quantity and quality of produced fruits. The results of present study showed the variation in growth and bearing properties of different combinations of Beyrouti and Dargazi cultivars with PyroDwarf and OH×F69 rootstocks throughout the studied years. The PyroDwarf rootstock greatly reduced the tree growth and enhanced fruit yield of both Dargazi and Beyrouti cultivars. According to the obtained results the PyroDwarf rootstock is recommended for Dargazi cultivar to reach the highest pear fruit yield under similar environmental condition of present study.
Pomology
Mohammadreza Safari Motlagh; Behzad Kaviani; Jaleh Ashegh
Abstract
Introduction: In recent years, applying humic acid has been common in enhancing the quantitative and qualitative characteristics of crops. The use of biofertilizers instead of chemical fertilizers has an effective role in increasing the health of plants, animals, and humans, and reducing environmental ...
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Introduction: In recent years, applying humic acid has been common in enhancing the quantitative and qualitative characteristics of crops. The use of biofertilizers instead of chemical fertilizers has an effective role in increasing the health of plants, animals, and humans, and reducing environmental pollution. Chemical fertilizers are gradually being replaced by biofertilizers. Strawberry is a fruit with high nutritional value. Choosing the right nutritional conditions such as fertilizers and suitable cultivation beds to achieve high quantitative and qualitative yield in this plant is inevitable. In recent years, the use of humic acid has been common in enhancing the vegetative and generative characteristics of crops. Humic acid is a rich source of potassium, phosphorus and nitrogen. The method of application of humic acid has an effective role in improving the quantitative and qualitative characteristics of plants. Combining some cultivation beds such as perlite, composts, and fertilizers including agricultural waste (such as rice bran and tea wastes) into soil cultivation beds have had an effective role for improving the quantity and quality of plants. Materials and Methods: A pot experiment was conducted to evaluate the effects of foliar application of humic acid and different cultivation beds on morphology, flowering and fruiting of two strawberry (Fragaria × ananassa) cultivars ‘Local’ and ‘Selva’ in Islamic Azad University, Rasht Unit, on 2016. Different concentrations of humic acid (0, 300, 600, and 1000 mg l−1) were applied as foliar application in two steps (late March containing three leaves and late April containing five leaves) on strawberries cultivated in different beds (usual soil and usual soil with rice bran, or perlite, or tea wastes). The experiment was carried out as factorial based on a randomized complete block design (RCBD) with four replications. Some traits including plant height, root number, root length, leaf length, shoot number, shoot length, shoot diameter, leaf number, node number, flowering time, flower diameter, flower number, fruit number and fruit weight were measured. Results and Discussion: Analysis of variance showed that the interaction effect of humic acid × cultivation bed ×cultivar on plant height, shoot length, shoot number, leaf number, root length, root number, flower diameter (p≤0.01), fruit weight, and fruit number (p≤0.05) was significant. The interaction effect of these three factors on shoot or stolon diameter, leaf length, flowering time and flower number was not significant. Results of mean comparison showed that the highest shoot or stolon number (14.82) were obtained in ‘Selva’ cultivar treated with 1000 mg l−1 humic acidcultivatedin usual soil with tea wastes. The highest fruit weight (35.45 g) and fruit number (15.41 per plant) were obtained in ‘Selva’ cultivar treated with 1000 mg l−1 humic acidcultivatedin usual soil with perlite. The maximum leaf number (16.03 per plant) was obtained in the treatment of 300 mg l−1 humic acid and the cultivation bed of usual soil and rice bran in ‘Local’ cultivar. Minimum fruit number (3.58) and fruit weight (8.23 g) were obtained in ‘Local’ cultivar cultivated in usual soil bed without humic acid. The highest number of root (19.56) was obtained in the treatment of 600 mg l−1 humic acid and the cultivation bed of usual soil with perlite in ‘Local’ cultivar. The highest amount of flower diameter (7.85 mm) was calculated in the treatment of 1000 mg l−1 humic acid and the cultivation bed of usual soil with tea wastes on ‘Selva’ cultivar. These results suggest that humic acid foliar application might be benefit to enhance fruit characteristics of strawberry. Totally, humic acid application increased growth and yield of strawberry. Since the most important parameters for increasing the quality of strawberry fruit is fruit characteristics, it is recommended to use 1000 mg l−1 of humic acid cultivated in the usual soil mixture with tea wastes. Strawberries are widely cultivated worldwide due to their high nutritional value. Chemical fertilizers have been used as a way to increase crop yields, but have led to problems such as nitrate accumulation, pot life, and poor quality and environmental pollution. Therefore, organic fertilizers have been used. Humic acid can improve quantitative and qualitative production by having properties such as providing more available essential elements and increasing plant resistance to various biological and non-biological stresses. A positive association has been reported between the use of humic acid and the increases in growth, yield and product quality in strawberries and other plants. Proper cultivation bed plays an important role in the optimal growth and development of plants. Salinity increases osmotic stress, ion toxicity, oxidative stress and food imbalance. The use of compost fertilizer and foliar application of humic acid increased the growth, yield and quality of strawberry fruit.
Mehdi Bagheri; Iman Roohollahi; Sasan Aliniaeifard
Abstract
Introduction: Management of rose plant structure plays an important role in flower production throughout the year and determines the amount of rose plant life span and influence plant development and quality of cut flowers (length, diameter and weight). In the past, roses were planted in a row, and their ...
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Introduction: Management of rose plant structure plays an important role in flower production throughout the year and determines the amount of rose plant life span and influence plant development and quality of cut flowers (length, diameter and weight). In the past, roses were planted in a row, and their structure was in the form of long vertical hedges, with annual pruning often involving, disbudding and pinching. Rose growers tend to bend non-producing shoots to increase light absorption and build more photosynthetic assimilates and increases the quality of the produced cut flowers. In this study was investigated for proper management of pruning of cut rose bud with an emphasis on degrees of shoot bending. Materials and Methods: The cutting's media were prepared from a combination of Cocopeat and Perlite at 50% equilibrium. The cuttings were planted in two-meter-long boxes 18 cm apart. From day 4, nutrient solution was injected into the substrates. Nutrient solution volume per plant was 550 ml per day, which was injected 11 times into the culture medium. In order to select the best plant structure architecture for producing the highest quality of the cut flowers, a factorial experiment was conducted based on a completely randomized design with two shoot pruning and bending treatments. During the bending process to increase the accuracy of the experiment, two bent shoots were counted for all cuttings, six days after bending treatment the dormant buds were activated in the primitive part of the stem and began to grow. Pruning of the buds was done in two levels of 50% pruning and without pruning. 45 days after bud removal, flower shoots were harvested, and samples were transferred to the laboratory for post-harvest evaluation. Chlorophyll and carbohydrate concentration, photosynthesis index, physiological, morphological and photosynthetic parameters were measured as well as vase life trait. Results and Discussion: Pruning of buds at 1% probability level was important on carbohydrate content and bending at 5% probability level on carbohydrate and vase life. Furthermore, the interaction between the two pruning treatment and bending at 1% probability level was significant on the carbohydrate content and vase life. In general, it could be concluded that by bending the shoots, the light penetrates into the plant structure, which ultimately increased photosynthesis and the amount of carbohydrates in flower buds. It could be concluded from the observations that bent shoots with appropriate angles could consume their carbohydrates for bud flower production. In other words, bending branches plays the role of factories which task is to deliver the photosynthetic production in the bending branches to the flower branches that are the most important consumer. The results showed that bending of branches (45 and 90 degree), with increasing light absorption and making more photosynthetic assimilates and changing their flow from bent branches to shoots, caused their proper growth and 30% increasing in the fresh and dry weight traits. The diameter of the bud and the length of the flower shoot increased post-harvest quality of the cut flower. Furthermore, the interaction of bud pruning and bending had a positive effect on carbohydrate content of flower shoots. On the other hand, the vase life were evaluated, which showed that the bending 45 degree had the highest vase life (22.5) and 120 degree had the lowest vase life. At treatment 120 degree (lowest postharvest survival), non-pruned treatments showed longer vase life (16 days) and lower pruned treatments after harvest (13.5 days). It also showed the highest fresh weight, dry weight, peduncle diameter and flower length are 45 degree. No significant difference was observed in the photosynthesis rate of a bent branch near the bed and vertical branches above the bed. By bending the branch at the right angle, it made the bent light branch more efficiently utilized and maintained its photosynthetic rate, although bending stress, at the high levels and in the manufacture of carbohydrates and other products. Photosynthesis for helping the plant eventually gained more carbohydrates from its vertical branches (flowering), and increasing carbohydrates will lead to a relative increase in quality, bud diameter and flower length and eventually vase life of the cut flower. Conclusion: The results of the bending treatment showed that the accuracy of the bending time and degree of 45° and 90° subsequently resulted in an increase in the quality of production.
Moslem Salehi; Vahid Reza Saffari; Shima Hasanzadeh Fard
Abstract
Introduction: Bedding plants, especially petunia is important element for urban landscaping and attracted the attention of landscapers. This is due to some properties such as growth habit and color. The petunia (Petunia hybrida L.) belongs to Solanaceae family that has annual and perennial varieties. ...
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Introduction: Bedding plants, especially petunia is important element for urban landscaping and attracted the attention of landscapers. This is due to some properties such as growth habit and color. The petunia (Petunia hybrida L.) belongs to Solanaceae family that has annual and perennial varieties. This plant is originally from Argentina, Brazil and Uruguay. Some plant growth regulators such as gibberellic acid (GA3) and vitamins including thiamine and ascorbic acid affect plant growth and development and may extend flowering period. Vitamin C affects cell division and cell growth in plants and is effective on the feeding cycle activity in higher plants and it has an important role in electron transport system. The concentrations of 50 and 100 ppm of vitamin C and thiamine can increase the plant height, leaf number, leaf area, fresh and dry weight, and chemical compounds of the Syngonium plant. The application of 100 mg/l of GA3 significantly increased plant height and the number of leaves of gladiolus.
Material and methods: The experiment was arranged in a factorial based on a completely randomized design with five replications. In this research, growth characteristics (lateral branch number, flower number, flower diameter, stem diameter, root length, and lateral branch length) and biochemical characteristics (chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, and reducing sugar) were measured. After seeding and transplanting the seedling at 6 leaf stage, plants sprayed at 4 various growth stages with following treatments:
1- Control
2- Vitamin C(100 mg/l)
3- Thiamin (100 mg/l)
4- Gibberellic acid (100 mg/l)
5- Vitamin C and Thiamin (The concentration of both 100 mg/l)
6- Vitamin C and Gibberellic acid (The concentration of both 100 mg/l)
7- Thiamin and Gibberellic acid (The concentration of both 100 mg/l)
8- Vitamin C, Thiamin and Gibberellic acid (The concentration of three 100 mg/l)
Data obtained from the measured parameters analyzed using statistical package SAS and means were compared using LSD test at the level of statistical significance of P˂0.05.
Results and Discussion: The results indicated that GA3 affected all the measured characteristics except carotenoids in comparison with thiamine and ascorbic acid. Meanwhile, the combined application of GA3 and ascorbic acid affected stem growth, root growth and flower diameter. Simultaneous use of GA3 and thiamine was effective on pigments, reducing sugar, carotenoids and flower number. The simultaneous application of three chemicals resulted in a considerable increase in growth and development traits, such as stem and root growth, flower number and diameter, pigments and reducing sugar compared to control. Generally, gibberellic acid will increase vegetative growth with impress cellular processes, including stimulation cell division and cell elongation. It was reported that the uses of ascorbic acid and gibberellic acid in Thyme (Thymus vulgaris) increased plant height and root length. Ascorbic acid makes a set of functions such as cell division and enlargements, cell wall development and other developmental processes in plants. Ascorbic acid affects plasma membrane proton pump and according to the acidic theory stimulates weaking cell wall and consequently will increase cell wall development and cell enlargement. It was found that thiamine significantly increased flower number in chrysanthemum .
Conclusion: The results indicated that the synergistic effects of this material can be used to enhance the growth and development of petunia. On the other hand, in arid and semiarid areas of the country, that drought and salinity stresses somewhat inevitable, these materials, especially vitamins are effective in reducing stress and increase flowering period.
Fatemeh Baniasadi; Vahid Reza Saffari
Abstract
Introduction: Catharanthus roseus (L.) belongs to Apocynaceae family is an important medicinal plant and also cultivated as an ornamental plant almost throughout the tropical and subtropical areas all over the world. Recently, the uses of natural substances are considered very helpful to improve plant ...
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Introduction: Catharanthus roseus (L.) belongs to Apocynaceae family is an important medicinal plant and also cultivated as an ornamental plant almost throughout the tropical and subtropical areas all over the world. Recently, the uses of natural substances are considered very helpful to improve plant growth and development. Application of plant growth regulators (PGRs) and vitamins are reported in many horticultural crops. Ascorbic acid is the most abundant antioxidant in plant which protects plant cells. This substance affects cell differentiation and growth. Now a day it is considered as a plant growth regulator. Thiamine or vitamin B1 is water soluble and one of the B complex vitamins. This study was conducted to investigate the effect of the ascorbic acid, thiamine, BA and GA on growth and biochemical parameters of periwinkle.
Materials and Methods: The experiment was perform as a completely randomized design with 5 replications at research greenhouse of Shahid Bahonar University of Kerman in 2014.The treatments used include spraying water (control), ascorbic acid 100 mg.l-1, gibberellic acid 100 mg.l-1, thiamine 100 mg.l-1, BA 200 mg. l-1 and combinations of two, three and four of them to determine the response of plants to these substances alone or in combination of them. When the seedlings become on 6-leavs stage, the first foliar spray was carried out. In other two steps was repeated with interval of 10 days. In this study, longevity of the flower, flower diameter, the number of lateral branches, branches length, fresh and dry weight, chlorophyll content and reduced sugars were measured. Chlorophyll content and reduced sugars were measured according to method of Somogy (1952) and Lichtenthder (1987), respectively.
Results and Discussion: The results showed that the effect of thiamine on the number of flowers was more pronounced than other substances. The lowest number of flowers per plant was found in plants treated with gibberellic acid. All growth promoter substances increased flower diameter. Combined application of BAwith gibberellic acid had more influence on this parameter than other treatments, and increase flower diameter about 25%. Ascorbic acid plays an important role in cell division, plasma membrane, proton pumps and enlargement cell. According to the theory of acidic growth, ascorbic acid weakens cell wall and increases cell enlargement. Among the applied treatments combination of banzyladenine, thiamine and ascorbic acid increased the number of lateral branches to 100%. Results showed that GA in all concentrations and combinations used in this experiment increased lateral branches length. Several reports in plants such as croton, hibiscus and pot marigold indicated that BA can increase the number of branches per plant. Therefore, BA is used to enhance branching and to reduce the total height of the plants. The highest fresh and dry weight were observed in plants treated with the combinations of BA, thiamine and ascorbic acid. Thiamine increased chlorophyll a content more than other substances. There was no significant difference between thiamine or thiamine combined with ascorbic acid treatment on chlorophyll b content. Thiamine in combinations with all the other treatments significantly improved carotenoids content compared to control. Chlorophyll plays a key role in plants for the absorption and utilization of light energy which used in photosynthesis. Therefore, effects of PGRs on chlorophyll biosynthesis or degradation influence directly on photosynthesis. Thiamine was reported that in some plants assist resynthesize of chlorophyll in plant without chlorophyll and increased growth and yield eventually. All the treatments significantly increased reducing sugar. Although all of the substances improved the amount of reducing sugar, the role of thiamine was more dramatic compared to other treatments. The greatest amount of reducing sugar 85.3 mg. g-1 fresh weight was observed in the combination of BA, thiamine and ascorbic acid. Thiamine is an essential part of the biosynthesis of pyrophosphate thiamine coenzyme which has an important role in carbohydrate metabolism. Application of vitamin c it was reported the increased soluble sugar in Chinese hibiscus.
Conclusion: Periwinkle is a bedding plant that the number of flowers and lateral branches is very important. BA with thiamine and ascorbic acid combination has the best effects on these traits and improved growth condition of it. On the other hand, application of gibberellic acid, either simple or combined with other materials, due to the excessive increase in plant height, led to the bending of the plant.
