z. jabbarzadeh

 Lisianthus (Eustoma grandiflorum) from Gentianaceae family is from wild flowers of north and west America. Lisianthus, a relatively new floral crop to the international market, quickly ranked in the top ten cut flowers worldwide due to its rose-like and blue flowers. It is also widely used as a flowering potted and bedding plant. Lisianthus ‘Mariachi Blue’ is cultivated as a cut flower. Salicylates have very beneficial effects on plant growth and development. The effect of phenolic compounds in many biochemical and physiological processes including photosynthesis, ion adsorption, membrane permeability, enzyme activity, flowering, stimulation of plant resistance systems, heat production and plant development has been proven. The most famous member of this group is salicylic acid, which as a simple phenolic compound, is naturally produced by plants. Salicylic acid (SA) is considered to be plant signal molecule that plays a key role in plant growth, development, and defense responses. Polyamines (PAs) are ubiquitous and biogenic amines that have been implicated in cellular functions in living organisms. In plants they have been implicated in a wide range of biological processes including cell division, cell elongation, senescence, embryogenesis, root formation, floral initiation and development, fruit development and ripening, pollen tube growth and plant responses to biotic and abiotic stress. Sodium nitroprusside is a nitric oxide releasing agent. Nitric oxide is a gaseous free radical that can disperse very rapidly through cell membranes due to its gaseous nature and medium shelf life, without a carrier. Nitric oxide (NO) is an unstable environmentally-friendly gas radical that is used to protect the postharvest longevity of different horticultural crops. In addition to controlling harvested crop senescence, NO is involved in many plant processes, e.g., germination, growth and development, photosynthesis, pigment synthesis, defensive system, and many others. In the present study, we investigated the effects of foliar application of salicylic acid, spermidine and sodium nitroprusside on some morpho-physiological characteristics and vase life of lisianthus flowers ‘Mariachi Blue’.

 This study was conducted based on a completely randomized design with 10 treatments, 4 replications which each replication containing 2 pots. The treatments were included spermidine at concentrations of 0.5, 1 and 2 mM, salicylic acid at concentrations of 0.5, 1 and 1.5 mM, sodium nitroprusside at concentrations of 50, 100 and 200 μM and control (without any application of growth regulators) as foliar application at intervals of 15 days for 2 months. Plant characteristics including leaf area, stem length, fresh and dry weight of leaves and flower, number of buds, flowers’ length and diameter, photosynthetic pigments and vase life were assayed. To perform analysis of variance and compare the mean of the studied traits, SAS software version 9.1 was used. The means were compared using the Tukey multi-domain method at a probability level of 1%. Also, Excel (2016) software was used to draw the chart. 

 The results obtained from analysis of variance in this study showed that the effect of growth regulators used in the study was significant at the level of 1% probability on all morphological traits measured, photosynthetic pigments and vase life of lisianthus flowers. Mean comparison graphs showed that salicylic acid, spermidine and sodium nitroprusside had a positive effect on some morphological traits, photosynthetic pigments and vase life compared to control. It can be concluded that, salicylic acid caused to increase all parameters except the flowers’ fresh weight compared to control. Spermidine increase stem length, leaf fresh weight, flowers’ fresh and dry weight, length, and diameter, chlorophyll index, chlorophyll b, and carotenoid and vase life of flowers. Also, sodium nitroprusside had beneficial effects on all parameters in this research except leaf area, leaf dry weight, chlorophyll a and vase life of flowers. Salicylic acid plays an important role in regulating some physiological processes of plants such as growth and development, ion uptake and transport, stomatal conductivity, and membrane permeability, which is effective in plant photosynthesis and with increasing photosynthesis, plant growth rate increases. Polyamines such as spermidine are involved in a wide range of developmental stages including cell division, embryogenesis, root growth, and flowering. Sodium nitroprusside is involved in the most important plant processes such as photosynthesis, respiration, growth and cell division. Probably, these growth regulators, due to their effect on plant growth, flowering, as well as photosynthetic pigments, have caused the increment of plant biomass and vase life.

 In the present study, the effect of salicylic acid, spermidine and sodium nitroprusside on some growth and flowering characteristics, photosynthetic pigment and vase life of Eustoma grandiflorum ‘Mariachi Blue’ was assayed. According to the results of the present study, it can be concluded that these growth regulators improved growth indices, flowering parameters, photosynthetic pigment and vase life of flowers. According to the results, the appropriate concentrations for salicylic acid were 1 mM, for spermidine, 1 mM and for sodium nitroprusside were also 50 and 100 μM.

 The genus Rosa from the family Rosaceae with over 150 species is one of the most important ornamental plants in the world. From a commercial point of view, cut roses play a key role in trade of cut flowers. Nitric oxide regulates key physiological processes that depend on the concentration of this compound such as hypocotyls growth, defensive responses, growth and development, photosynthesis, and phytoalexin generation in stressful conditions. Polyamines are key biomolecules that have a role to play in the regulation of many plants’ growth and development processes and their responses to different environmental stimuli. This study was performed to investigate the effect of foliar application of sodium nitroprusside (as a NO donor) and putrescine (as a polyamine) on ‘Avalanche’ rose in hydroponic conditions.

 This study was conducted in the research and production greenhouses of Urmia University and the research laboratory of the Department of Horticultural Sciences of the Faculty of Agriculture in 2019-2020 on rose (Rosa hybrida ‘Avalanche). This experiment was conducted as a factorial trial based on completely randomized design with two factors including sodium nitroprusside in four concentrations of 0, 50, 100 and 200 μM and putrescine in four concentrations of 0, 1, 2 and 4 mM with 3 replications as a foliar application under hydroponic conditions in greenhouses and in pots. The treatments were applied two weeks after transplantation, every 15 day-interval for 4 months. In order to investigate the effects of putrescine and sodium nitroprusside on some morphological and physiological characteristics of plants, two weeks after the end of treatments, sampling was performed to measure morphological and physiological characteristics. The measured indicators included: fresh and dry weight of flowering stem, chlorophyll a, b and total chlorophyll, carotenoids and also in the postharvest stage were guaiacol peroxidase and ascorbate peroxidase enzymes activity and bending of flowering stem. The SAS software version 9.2 was used to analyze the variance and compare the mean of the studied traits. Comparison of means was performed using the Tukey’s range test method at a probability level of 1 and 5%. Also, Excel (2016) software was used to draw the graph.

 According to the means comparison of measured parameters, sodium nitroprusside along with putrescine increase the flowering stem fresh and dry weight, photosynthetic pigments of leaves and antioxidant enzymes activities at the postharvest stages. Sodium nitroprusside at a concentration of 50 μM with 4 mM putrescine increased the fresh and dry weight of the flowering stem. Also, the concentration of 100 μM sodium nitroprusside with 4 mM putrescine significantly increased chlorophyll a, b, total chlorophyll and carotenoid content compared to control. It should be noted that preharvest application of sodium nitroprusside along with putrescine cause to improve postharvest characteristics of rose. In this research, application of 100 and 200 μM SNP alone or with different concentrations of putrescine increased guaiacol peroxidase and ascorbate peroxidase activity and reduced bending of flowering stem of rose ‘Avalanche’ at the postharvest stage. Probably polyamines (such as putrescine) and nitric oxide increase photosynthesis potential with increasing photosynthetic pigments and protecting cell membranes thus increase growth and flowering traits of plants such as increasing the flowering stem weight of rose in this research. At postharvest stage, senescence of flowers is an inevitable phenomenon that cause to produce free radicles in plants. Free radicles injure the plant membranes lipids and change the antioxidant enzymes activities. This despite the fact that nitric oxide and putrescine protect antioxidant enzymes against free radicles as a result can improve vase life of rose.   

 Based on the results of the present study, it can be concluded that putrescine, with SNP, improves growth characteristics as well as increases the postharvest traits and quality of cut flowers of rose.  According to the results, it is observed that among the different concentrations of putrescine, the concentration of 4 mM had the greatest effect on the growth and physiological parameters of rose while the concentration of 100 and 200 μM sodium nitroprusside had a greatest effect on physiological characteristics and postharvest traits of rose. In general, both SNP and putrescine had a positive and favorable effects on improving growth and postharvest indices, but the effective concentration varied depending on the type of parameter.

Gerbera is one of the most important cut flowers in the world and belongs to the Asteraceae family. Due to its diverse and adaptable species for growth with a wide range of climatic conditions, this flower has become a profitable cut flower for growers. Polyamines in plant tissues act as a potent factor in preventing the production of ethylene. Polyamines and ethylene have antagonistic effects (anti-aging and aging effects), so that the balance of these two hormonal groups in plants is very important for plant tissues. The balance between the two opposing regulators leads to a delay or acceleration in the aging process. Mycorrhizal fungi can be useful in hydroponic greenhouse systems, which increase the amount of CO2 in greenhouses by increasing photosynthesis in plants, as well as CO2 emissions in the control environment, which both optimally manage the environment and increase the yield and quality of plant products. Due to the economic importance of cut flowers, it seems necessary to provide treatments (such as the use of putrescine and mycorrhiza) to increase the quality and longevity of this plant. This study was conducted in the research and production greenhouses of Urmia University and the research laboratory of the Department of Horticultural Sciences of the Faculty of Agriculture in 2019-2020. This study was performed as a factorial experiment in a completely randomized design with three replications, each replication consistedd of three pots and each pot contained a plant. The factors of this experiment were Mycorrhizal fungi inoculation (with and without inoculation) during the transplanting process to the culture medium near the roots, and putrescine at four concentrations of 0 (control), 1, 2, and 4 mM, were applied two weeks after transplantation, every 15 day-interval for three months. In order to investigate the effects of putrescine and mycorrhizal fungi on some morphological and physiological characteristics of plants, two weeks after the end of treatments, leaf sampling was performed to measure physiological characteristics. Effects of putrescine and mycorrhizal fungi were assayed in some morphological characteristics including leaf number, leaf length and leaf area, fresh and dry weight of leaves and some physiological parameters including chlorophyll index, chlorophyll content (a, b and total) and soluble sugar as well as vase life and petal’s anthocyanin during postharvest time. The SAS software version 9.1 was used to analyze the variance and compare the mean of the studied traits. Comparison of means was performed using the Tukey’s range test method at a probability level of 1 and 5%. Excel (2016) software was also used to draw the graph. According to the comparison of means, putrescine, along with mycorrhizal fungi, increased the number of leaves, leaf area, and the fresh and dry weight of the leaves as well as chlorophyll index, chlorophyll a, b and total and carotenoid content of leaves. In this study, inoculation with mycorrhiza reduced leaf length but increased leaf area resulted in that mycorrhiza could increase leaf blade because of increasing cytokinin in plant. Putrescine with mycorrhizal fungi, increased leaf growth, photosynthesis of plant and carbohydrates production. In the literatures, it is reported that, the vase life of cut flowers is a very important point in choosing them as great cut flowers. The results showed, putrescine and mycorrhiza had increased the vase life of gerbera flowers, therefore increased the quality of this plant. Putrescine and mycorrhiza also increased the amounts of anthocyanins in the petals, and by the sixth day, the highest levels of anthocyanins were observed in the petals. Probably, the reason for increasing the anthocyanins on the sixth day is the presence of carbohydrates stored in the flower, which due to the reduced respiration and carbohydrate consumption in this process. Based on the results of the present study, it can be concluded that putrescine, with mycorrhizae, improved growth characteristics as well as increasing the postharvest life and the quality of cut flowers of gerbera. It is also observed that among the different concentrations of putrescine, the concentration of 2 mM had the greatest effect on the growth and physiological parameters as well as vase life of gerbera.

Gerbera jamesonii is a permanent, herbaceous and chilling-sensitive plant species from the family Asteraceae that is native to hot regions. The species has high color diversity and it is among the top ten cut flowers in the world. Fulvic acids are a family of organic acids, natural compounds, and components of the humus (which is a fraction of soil organic matter). They are similar to humic acids, with differences being the carbon and oxygen contents, acidity degree of polymerization, molecular weight and color. Fulvic acid remains in solution after removal of humic acid from humin by acidification. Fulvic acids are of relatively low molecular mass and less biologically active than humic acids. Among micronutrients, Iron (Fe) is a cofactor for approximately 140 enzymes that catalyze unique biochemical reactions and is an essential element for growth of plants. Lack of iron causes young leaves yellow and photosynthesis activity reduce significantly and consequently biomass reduce. Iron plays many essential roles in plant growth and development, including chlorophyll synthesis, thylakoid synthesis, chloroplast development, contribution in RNA synthesis and improvement the performance of photosystems. Nano-fertilizers can be substituted for conventional fertilizers. Studies showed that the effect of nano-particles on plants can be beneficial (seedling growth and development).

In order to investigate the effect of different concentrations of fulvic acid and iron nano chelate on flowering of gerbera as well as flower vase life of gerbera cv. Dune, an experiment was conducted as a factorial based on a completely randomized design with three replications during the years 2016-2017. The medium was included peat moss 65%, perlite 30% and cocopeat 5%. The seedlings of tissue cultured plants were planted into pots (size-20) (volume 7 L, height 19 cm, diameter 24 cm) in hydroponic greenhouse conditions. Day/night temperature regime was set at 20-25/13-16°C and light intensity at 400-500 μmol m-2 s-1. The plants were fed three times a week. The treatments were: fulvic acid at four concentrations of 0 , 50, 100 and 250 mg L-1 as drench and iron nano chelate at 4 concentrations of 0, 1, 2 and 4 gr L-1 as foliar application  (15 days intervals for 4 months),. Two weeks after the last treatment, morphological parameters were measured. They were included flower fresh and dry weight, flowering stem length, flower longevity and vase life and the number of days to the appearance of flower buds. Also, the recorded physiological parameters included chlorophyll a, b and total chlorophyll, chlorophyll index and carotenoid.

The results of this study showed that, flower dry weight was increased with increasing the concentration of iron nano chelate. The highest flower dry weight )6.43g( was obtained from plants treated with 4 g L-1 iron nano chelate and the lowest one )5.57 g( from control plants, but flower fresh weight was not affected by these treatments. The highest length of flowering stem was observed in treatment of 2 g L-1 iron nano chelate. The lowest time to flowering was obtained from 50 mg L-1 fulvic acid without application of iron nano chelate. The results of means comparisons showed that fulvic acid and iron nano chelate caused to increase flower longevity significantly. The highest flower longevity (19 days) was obtained from 250 mg L-1 fulvic acid and 1 g L-1 iron nano chelate and the lowest mean (12.66 days) was related to control plants. Also, most of treatments caused to increase vase life compared to control. The highest vase life (14.66 days) was observed in 1 g L-1 iron nano chelate without fulvic acid while the lowest mean (6.66 days) was observed in control. Chlorophyll content (chlorophyll a, b and total chlorophyll) and carotenoid content of gerbera increased with increasing concentrations of fulvic acid and iron nano chelate in compared with the control. 

According to the results obtained from this research, application of fulvic acid and iron nano chelate have a positive effect on most flowering and biochemical indices. Application of low concentrations of fulvic acid (50 mg L-1) supplemented with iron nano chelate caused to early flowering. Fulvic acid didn’t have any effect on flowering stem length and its application reduced the flower dry weight. While combined application of fulvic acid and iron nano chelate caused to increase flower longevity. Also iron nano chelate caused to increase flowering stem length, vase life and flower dry weight. In most of the biochemical indices, combined treatment of 100 mg L-1 of fulvic acid and 2g L-1 of iron nano chelate had better or favorable result on measured indices compared to the control treatment although the highest concentration of treatments did not have a negative effect and sometimes in some indicators also have more impact. Among these treatments, the concentrations of 100 and 250 mg L-1 fulvic acid and 2 and 4 g L-1 iron nano chelate can be effective for gerbera plant.