Zinnia is a very attractive and beautiful ornamental plant due to the diversity of color and flowering period. The effect of cycocel and pot size was studied on growth and flowering of zinnia in a factorial experiment based on a randomized complete design with two factors: cycocel at 3 levels (0, 1000 and 2000 ppm) and pot size at 4 levels (10, 12, 14 and 16 cm) with 12 treatments and 3 replications. The interaction results showed that cycocel and pot size had a significant effect on all studied traits, that 2000 ppm cycocel in 12 cm pots produced the minimum height and that 16 cm pots treated with 1000 ppm cycocel or without cycocel treatment produced the maximum plant height. Maximum flowering period was related to 14 cm pots × 1000 ppm cycocel that had no significant difference with plants in 16 cm pot size in all three concentrations of cycocel. Minimum flowering period was related to 10 cm pot size at all three concentrations of cycocel. Zinnias planted in 10 cm pot size without cycocel treatment exhibited the minimum fresh weight and in 14 cm pot size without cycocel treatment exhibited the maximum root fresh weight. Overall, flowers in 14 and 16 cm pot sizes treated with 1000 ppm cycocel were found to be the best treatments.

Many experiments have been carried out to decrease the negative effect of drought stress and obtain suitable growth under water deficit conditions. Application of plant growth regulators (especially growth retardants) is one of the proposed methods. This study was conducted to investigate the effect of Cycocel application on growth of two olive cultivars (Shengeh and Roghani) under water stress condition. The design of experiment was completely randomized with six replications (Factorial arrangement). Treatments included irrigation intervals (2, 4, 6, 8 weeks) and Cycocel concentrations (0, 500,1000,2000,4000 mg per litter). Some indices such as height, chlorophyll, leaf area, root, and shoot weight (fresh and dry) were measured. Results indicated that interaction of C.C.C treatment and irrigation intervals on height of olive cultivars was not significant, probably due to the response of these cultivars to concentrations of C.C.C. Although drought stress decreased the number of leaves in both cultivars, the application of CCC (500 mg per litter) thwarted the adverse effects of drought stress. Cycocel increased chlorophyll content significantly (500 mg per litter in Roghani and Shengeh and 6 weeks irrigation interval). Cycocel application decreased leaf area, but in Shengeh cultivar increased leaf area in 6 week irrigation interval. Overall, the results indicated that the application of Cycocel with concentration of 500 mg per litter in 6 week irrigation intervals in both cultivars (Roghani and Shengeh) was the best treatment for controlling the adverse effects of drought. Also, results indicated that such changes were dependent on Cycocel concentration and drought level.

Growth retardants are natural or synthetic chemical substances which are directly applied to crops to alter some structural processes. It is expected that these alterations modify hormonal balance and growth leading to increased yield, improved crop quality or facilitated harvesting. Cycocel (CCC) or chlormequat chloride (2-chloro ethyl trimethyl ammonium chloride) as a synthetic growth retardant has been recommended for wheat since 1960s. Cycocel inhibits gibberellin biosynthesis via blocking ent-kaurene synthesis in the metabolic pathway of gibberellin production, resulting in reduced amounts of active gibberellins and consequent reduction in stem elongation. The stem shortening effect of cycocel in such cereals as wheat seems to be less important, due to release of many dwarf and semi dwarf wheat cultivars. However, using cycocel in cereal fields would be inevitable if its effect on grain yield is definite and this area needs further investigation. Importance of cycocel is greater under environmental stress conditions, and more research needs to be focused on cycocel-induced stress tolerance. In this paper, the current knowledge and possible applications of cycocel, which can be used to improve the growth and yield of cereals, have been reviewed and discussed. The role of cycocel to mitigate the harmful effects of drought and salt stresses in cereals is also examined. Furthermore, various biochemical and physiological processes leading to improved cereal crop production under the influence of cycocel are discussed.

Basil (Ocimum basilicum) is an annual plant which belongs to the Lamiaceae family. It used as a drug, spice and fresh vegetable. Drought stress is one of the important limiting factors of plant growth. Water stress has significant effects on morphological and biochemical characteristics of purple Basil. As the soil water content decreases, the plant height, stem diameter, number and area of leaves, leaf area index (LAI), herb yield and leaf chlorophyll contents (a,b and total chlorophyll) decrease, as well. However, the amounts of anthocyanin and proline increase. Cycocel (CCC) which chemically called chlormequat chloride is an alkylating agent and a quaternary ammonium salt.. Cycocel is used as plant growth regulator. Application of Cycocel increases the number of siliques/ plant, seed yield and dry matter produced of oilseed rape. Cycocel application decreases the plant height and increases the yield level and protein percentage of seed in faba bean. This research was performed to investigate the effect of Cycocel on morphological characteristics, the percentage of nitrogen and potassium of basil plants under drought stress conditions
This research has been conducted in the research station of Shahid Bahonar University of Kerman with 56o 58' E longitude, 30o 15' N latitude, and 1753.8 altitudes. According to the regional information from 1952 to 2005, the average temperature was 17.1 o C, the average rainfall was 154.1 mm, the average annual relative humidity is 32%, and the climate of Kerman according to De Martonne method is semiarid. A split plot experiment based on RCBD with three replications was employed. Three levels of irrigation, including 50 (severe stress) (I3), 75 (mild stress) (I2) and 100 (full irrigation) (I1) percent of crop water requirement were assigned to the main plots while five levels of Cycocel application (zero (control), 500, 1000, 1500, 2000 milligrams per litre) were assigned to the sub-plots. Cultivation was carried out in March and harvested in late June. In this study the plant height, fresh and dry weight of root and shoot, root to shoot dry weight ratio, percentage of nitrogen and potassium, leaf relative water content and leaf area index were measured. For its statistical calculation, SAS (v. 9.1) software and for the comparison of the averages the Duncan’s test was used. The level of possibility used in the analysis was five percent.
The result of the analysis of variance of measured traits has shown in Table 1. Data analysis of variance (Table 1) shows different levels of irrigation, Cycocel and irrigation with Cycocel interaction were significant at the level of one percent on plant height. Effects of different irrigation treatments and Cycocel concentration on fresh and dry weight of shoot were significant at one and five percent, respectively. However, the effect of irrigation and Cycocel interaction on shoot dry weight was not significant. Root fresh and dry weight were influenced by irrigation levels (Table 1). The effect of irrigation and Cycocel interaction on root dry weight, percent of nitrogen and dry weight of root to shoot ratio was significantat one percent. The effect of irrigation on root to shoot dry weight ratio was not significant. Moreover, the effects of Cycocel treatments on root to shoot dry weight ratio were significant at the five percent level. The effect of irrigation, Cycocel on percent of nitrogen and potassium was significant and potassium decreased with the increasing of water stress.
The highest percentage of potassium (2.26%) belonged to the full irrigation and the concentration of 2000 milligrams per litre Cycocel and the lowest belonged to the interaction of severe stress and zero, 500 and 1000 milligrams per litre Cycocel. Irrigation and Cycocel had a significant influence on leaf relative water content at the level of one percent.
According to the results which obtained through this study, in basil plant, root fresh and dry weight, shoot fresh and dry weight, leaf area index, leaf relative water content and plant height reduced by increasing drought stress. Root-shoot dry weight ratio increased in response to increasing stress in all the plants which treated by Cycocel . Cycocel treatments reduced plant height, root fresh and dry weight, shoot dry weight and LAI. Leaf relative water content and shoot fresh weight increase with increasing the concentrations of Cycocel. The interaction of 2000 milligram Cycocel per litre with irrigation has the greatest effect on the traits.

In order to investigate the effect of growth regulators on a number of morphological characteristics of cotton cultivars, the present research was conducted as a factorial experiment in a randomized complete block design with 3 replications at Hashemabad Cotton Research Station, Gorgan in 2016 and 2017. Factors included growth regulators treatments with 6 levels (control, benzyl adenine, abscisic acid, salicylic acid, brassinosteroid, and cycocel) and three cotton cultivars of Golestan, Kashmar, and Shayan. Growth regulators affected most traits. Cycocel produced the highest number of bolls per plant (13.4) and abscisic acid reduced the number of bolls by 25% compared to the control. Salicylic acid increased, and abscisic acid and cycocel decreased the distance from the first sympodia to the ground. The highest number of fifth sympodia nodes, respectively, with an average of 7.17, 7.09 and 7.07, was allocated to foliar application with salicylic acid, brasinosteroid and cycocel, and the lowest with 6.07 and 6.13 belonged to abscisic acid and benzyl adenine. Overall, salicylic acid and benzyl adenine were able to increase the internodes length and abscisic acid and cycocel to reduce it. Therefore, with the aim of selecting cultivars with higher boll number, it is possible to use growth regulator of brasinosteroid or cycocel, and Golestan and Shayan cultivars, but to select a higher early maturity percentage, salicylic acid or cycocel, and Kashmar and Shayan cultivars can be used. In general, it is possible to recommend the cycocel growth regulator and Shayan cultivar.

In order to investigate the effect of cycocel and micronutrient consumption on yield, physiological traits, and antioxidant content of maize under low irrigation conditions at the end of the season, a split factorial experiment was carried out based on a randomized complete block design with four replications in Safiabad Agriculture Research Center in Dezful during two cropping years 2017-18 and 2018-19. The main treatment included water stress with three levels control (without water stress), water stress in female flower formation stage and water stress in grain swelling stage. Also, foliar application of cycocel at three levels of control (no use of cycocel), 442.5 ppm, and 885 ppm and three levels of micronutrient fertilizers, namely control (no fertilizer application), foliar application of 1000 g. ha-1, and foliar application of 1500 g. ha-1 were considered as the sub-factors. Results of the combined ANOVA showed that the interaction of the effects of year, stress, micronutrient, and cycocel on relative water content, proline and grain yield and also the interaction of the effects of stress, micronutrient, and cycocel on hydrogen peroxide, glutathione peroxidase, and soluble proteins were statistically significant (p≤0.01). The results also showed that the highest activity of superoxide dismutase enzyme was obtained under stress conditions at the grain swelling stage, which showed an increase by about 37% compared to the irrigation treatment under optimal conditions. Foliar application of 1500 g. ha-1 micronutrient and 885 ppm cycocel in non-stress conditions increased the average grain yield (11500 kg. ha-1) in the second year by about 85% compared to stressed condition at grain swelling stage and no application of micronutrient and cycocel. In general, to increase grain yield under optimal irrigation conditions and reduce the drop in stress conditions, growth regulators such as cycocel with a concentration of 885 ppm and micronutrient foliar application at 1500 g. ha-1 are recommended.

Wheat is a major staple food crop in the world. Although all abiotic stresses adversely affect the wheat growth and production, water scarcity imposes the most severe effects on this crop. Drought stress is also believed to affect the uptake, transport and accumulation of key inorganic nutrients in plants. Silicon occurs abundantly in soils, but in the field of plant growth the other inorganic elements for plant growth are more important than Silicon. However, Silicon plays an effective role in plants under stressful conditions. Silicon entails useful effects in plants under water-deficit treatments, with respect to drought-induced regulation of metabolic processes and water relations. Of several plant growth regulators, Cycocel (CCC) is believed to be very effective in masking the adverse effects of different abiotic and biotic stresses on crops as well as being an essential component of the signal-transduction pathways operating in plants exposed to environmental cues including drought stress. Exogenously applied CCC is believed to affect absorption and transport of nutrients, stomata regulation, growth and photosynthetic rate, chlorophyll synthesis and transpiration. The literature has little information on the role of Silicon and CCC applied in combination in alleviating drought-induced injurious effects on plants. Therefore, in the present study, we appraised the effects of exogenous Silicon and CCC applied individually or in combination on wheat growth and grain yield under water-deficit conditions.

This study was carried out in Tiran province, Isfahan, Iran during 2018-2019, as a split-split plot design in randomized complete block with three replications. The main plots considered irrigation regimes (full irrigation and 40% field capacity irrigated), sub-plots considered Silicon and cycocel application (control, 3.6 g l-1 Silicon, 210 mg l-1 Cycocel, and 3.6 g l-1 Silicon + 210 mg l-1 Cycocel) and sub-sub plots considered two wheat cultivar (Sirvan and Chamran). All measurements based on fresh plant samples were done before the grain-filling stage. Measurements included relative water content, soluble sugars and soluble proteins; activities of peroxidase, ascorbate peroxidase, catalase, superoxide dismutase, levels of hydrogen peroxide, malondialdehyde, concentrations of Ca, K and Mg and leaf water potential. At maturity, yield and yield components were measured. Statistical analysis of data was performed using the MINITAB statistical software.

Drought stress caused a considerable reduction in yield and yield components and relative water content of both cultivars. Application of Silicon and cycocel effectively improved these parameters in water-deficit treatments. Moreover, water-limited conditions markedly promoted the activities of key antioxidant enzymes including peroxidase, ascorbate peroxidase, catalase and superoxide dismutase, while enhancing the accumulation of soluble sugars, potassium, magnesium and calcium in leaf tissues. Application of Silicon and cycocel further enhanced the activities of the key antioxidant enzymes and accumulation of osmolytes, and decreased the levels of H2O2 and malondialdehyde in drought stressed plants. Synergistic effects of Silicon + cycocel application on yield and physiological parameters were apparent compared with Silicon or cycocel applied separately. Water-stress alleviation and yield improvement in the wheat cultivars by Silicon and cycocel application was attributable to partly improved osmotic adjustment and antioxidant activity as well as to more favorable water status under stress conditions.

Foliar application of Silicon, CCC and especially the combination Silicon + CCC, markedly improved grain yield and yield components of the two wheat cultivars under water-deficit. In Silicon, CCC and Silicon + CCC treatments, grain yield was 15.63%, 16.60% and 24.32% higher respectively, than with no foliar application under water stress in cv. Chamran, and 10.25%, 16.02% and 19.25% higher in cv. Sirvan. The results of the study highlight the role of Silicon and CCC application in regulating water-stress response of wheat, suggesting that Silicon and CCC are involved in physiological activities. These results showed positive effects of Silicon and CCC in terms of increased antioxidant activity as well as relative water content and leaf water potential. In addition, Silicon and CCC stimulated the active accumulation of some osmolytes in leaves of water-stressed wheat plants, which suggests enhanced osmoregulation ability. The synergistic effects of Silicon + CCC application on yield and physiological parameters were greater than of Silicon or CCC applied separately. Therefore, proper application of Silicon and CCC might result in increased production of wheat, particularly in dryland areas.

In order to investigate the effect of cycocel on different growth aspects of two olive cultivars (Mary and Mission), a greenhouse experiment was conducted taking into account three factors of: cycocel at three levels (0, 500 and 1000 mg L-1), drought stress of three levels (irrigated at 5, 10 and 15 days intervals) and two olive cultivars (Mary and Mission) in a factorial experiment based on randomized complete block design of three replicates during four months. The results showed that both cycocel treatments decreased leaf area, increased leaf thickness, chlorophyll content and soluble sugars, but no significant difference in leaf temperature was observed compared with the control. High cycocel treatments (1000 mg L-1) increased proline and relative water content (RWC) compared with the other treatments. Also, results showed that increased periods of drought reduced leaf area, RWC, but increased leaf thickness, leaf temperature, chlorophyll content, proline and soluble sugars in both cultivars. In above-mentioned parameters, 'Mission' showed higher resistance to drought stress than 'Mary'. Results suggested that cycocel treatment can neutralize some negative effects of drought stress in 'Mary' and 'Mission' of olive trees.

In order to study the effects of nitrogen fertilizer and growth regulator of cycocel on nitrogen use efficiency, some physiological traits and grain yield of rice (Oryza sativa L.), a factorial experiment was conducted based on randomized complete block design with three replications at the farm of Someasaraye from Gilan Provence during 2014-15. Treatments were included nitrogen rates in four levels (without nitrogen application as control (N0) and application 100 (N1), 150 (N2) and 200 (N3) kg N ha-1 as urea) and four cycocel levels (without cycocel as control (C0), application of 0.8 (C1), 1.6 (C2), 2.4 (C3) L ha-1). The results showed that foliar application of 2.4 L ha-1  cycocel and 200 kg N ha-1 increased grain filling rate, grain filling period, effective grain filling period, the number of grains per ear and 1000 grains weight. The highest dry matter remobilization from shoots and stem (114.6 and 57.91 g.m-2  respectively) and the highest dry matter from shoots and stem reserves contribution to grain yield (47.91% and 27.04%, respectively) were obtained  without  nitrogen application and foliar application of 2.4 L ha-1 cycocel. The highest grain yield was obtained in application of 200 kg N ha-1 and the lowest it belongs to no nitrogen application. The highest nitrogen use efficiency was obtained in application of 100 kg N ha-1 and the lowest it belongs to 200 kg N ha-1. The highest nitrogen use efficiency was obtained in application of 2.4 L ha-1 cycocel and the lowest it belongs to no cycocel application. Foliar application of 0.8, 1.6 and 2.4 L ha-1 cycocel increased 12.47%, 21.68% and 32.05% from grain yield respectively in compared with control. It seems that foliar application 2.4 L ha-1 cycocel and application of 200 kg N ha-1 can be as a proper tool for increasing grain yield of rice.

Poinsettia (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.).

 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 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.