Different Concentrations Of Putrescine Research Articles

Histological studies on induction of somatic embryogenesis in mangabeira

The Hancornia speciosa Gomes (Apocynaceae), is a fruit tree known as mangabeira and officially listed as a genetic resource with food potential in Brazil. The aim of this investigation was to conduct histological studies on inducing maturation of somatic embryos from explants of Hancornia speciosa Gomes. For callus induction, leaf and nodal segments of the Terra Caída accession were cultured in media with different concentrations of putrescine (0, 250, 500, 750, and 1000 µM) in MS medium with 10 mg/L of 2,4D, 5 mg/L of BAP, 1 g/L of activated carbon, and 30 g/L of sucrose, and gelled with 3 g/L of Phytagel®. At 90 days of culture in multiplication medium, the embryogenic calluses were identified and selected for the maturation phase of somatic embryos in media composed of MS salts combined with two concentrations of BAP (10 and 15 mg/L) and two concentrations of polyethylene glycol – PEG 2000 (0% and 2%) with 30 g/L of sucrose, 1 g/L of activated carbon, and 4 g/L of Phytagel®. At 90 days of culture in multiplication medium (medium II) and at 60 days of culture in maturation medium (medium IV), the callus samples were fixed in FAA. After that, the samples were infiltrated in 100% ethanol + liquid resin (1:1) for 2 hours and then in activated resin = infiltration solution for 24 hours in the refrigerator. After drying, the slides were fixed with glass varnish and then evaluated in an optical microscope (Zeiss/Jenamed2), and photomicrographs (Axiocam software) were taken of the prepared slides. The results obtained in the different histological analyses of the Terra Caída accession of Hancornia speciosa Gomes are important to show the response of the nodal and leaf segments in inducing embryogenic calluses and possible maturation of somatic embryos, providing information that collaborates in validation of future protocols of somatic embryogenesis for this species.

Exogenous Putrescine Changes Biochemical (Antioxidant Activity, Polyphenol, Flavonoid, and Total Phenol Compounds) and Essential Oil Constituents of Salvia officinalis L.

Polyamines are small polycationic molecules containing amines that are present in almost all cells of living organisms and act in a wide range of physiological processes, growth, and development, biological and protection of cells against free radicals. This research is based on principal component analysis (PCA) and calculation of selection criteria (SC) to investigate the effect of foliar spraying of polyamine putrescine on essential oil yield, essential oil compounds, antioxidant activity, and biochemical compounds (polyphenol, flavonoid, and total phenol compounds) of Salvia officinalis. The treatments used included four levels of putrescine, Put (Control: 0, Put1: 500, Put2: 1000, and Put3: 1500 mg L-1 ) with five replications. Based on our results, four factors had eigenvalues≥1 and showed a cumulative variance percentage of 92.57 % by applying different concentrations of putrescine. According to the results of this research, putrescine had significant effects on the amount of total phenolic compounds, flavonoids, and antioxidant activity. The best attention to improving the essential oil yield of sage was 1000 mg L-1 . The crucial essential oil compounds of different Put treated sage were: cis-thujone (35.34 %), camphor (15.60 %), trans-thujone (9.90 %), 1,8-cineole (9.46 %), α-humulene (3.85 %), viridiflorol (3.62 %), camphene (3.58 %), α-pinene (3.50 %), β-pinene (2.78 %), and limonene (1.23 %). The results showed that the amount of total phenol, the phenolic composition of catechin, and the antioxidant activity of sage plant extract increased significantly when putrescine was used at 1000 mg/liter. Results can use the current research to optimize the production management of medicinal plants and improve the quality of their products. In addition, the advantage of using putrescine is that it increases antioxidants and reduces oxidative damage, and can replace medicinal plants as suitable natural preservatives, thus improving food quality and safety.

Effect of putrescine and proline on proflies of GABA, antioxidant activities in leaves of three Citrus species in response to low temperature stress

This study was carried out to assess antioxidant activities and defense role of putrescine and proline in leaves of three Citrus species under low temperature stress. Branches of three Citrus species (C. reticulata L., C. sinensis L. and C. paradisi L.), sprayed with putrescine 0, 5, 10 mM and proline 0, 15, 20 mM. 24 h after application, containers containing treated shoots exposed to temperatures 1, − 1 and − 3 °C for six hours. The amount of hydrogen peroxide, flavonoids, phenolic compounds and antioxidant capacity increased with temperature reduction to − 3 °C. HPLC analysis showed that low temperature (− 3 °C) induces the levels of Gamma Aminobutyric Acid (GABA) in leaves of all species. The comparison of the HPLC patterns of the three species showed that GABA levels in treated leaves increased than control. The application of different concentrations of putrescine and proline decreased production of hydrogen peroxide but improved antioxidative activities of leaves under low temperatures. Putrescine 10 mM and proline 20 mM showed the highest effects than the other levels. The highest value of hydrogen peroxide was observed in leaves of control (putrescine and proline 0 mM) under − 3 °C but its lowest level was seen in leaves treated with proline 20 mM and putrescine 10 mM in all three species of Citrus. The highest level of phenolic compounds, flavonoids and antioxidant capacity were observed in leaves treated with putrescine 10 mM and proline 20 mM at − 3 °C. Putrescine 10 mM and proline 20 mM showed the highest impact on reduction of the damages caused by low temperature stress.

Physio-chemical responses of exogenous calcium nanoparticle and putrescine polyamine in Saffron (Crocus sativus L.).

The aim of this study was to investigate the effect of calcium nanoparticles (CaNP) and putrescine polyamine on some physiological and biochemical properties of saffron (Crocus sativus L.) under the control condition. Saffron corm was treated by different concentrations of putrescine (0, 0.25, 0.5, 1, 2 mM) and CaNP (0, 0.25, 0.5, 1, 1.5 g/l). The treatment of corm with putrescine and CaNP separately caused a significant increase in morphological parameters. Changes in biochemical parameters were also significant. Compared to other concentrations, the highest concentration of putrescine (1 mM) and CaNP (1 g/l) treatment in the plant showed the greatest effect. The combined effect of putrescine and CaNP treatment on morphological parameters was significant. The results of HPLC analysis showed that CaNP treatment alone is more effective on crocin, picrocrocin, and safranal content than the combined effect of CaNP and putrescine. The present study reported the functional potential of CaNP and putrescine combination to increase growth and phytochemical properties in Crocus sativus.

Postharvest Dip Application of Putrescine and Salicylic Acid Delayed Postharvest Quality Deterioration and Extended the Storage Life of Lime (Citrus Aurantifolia Swingle) Fruit

ABSTRACT Potential of putrescine (PUT) and salicylic acid (SA) as postharvest dip treatments on maintaining quality and extending the shelf life of lime (Citrus aurantifolia Swingle) fruit cv. Local was investigated. Fruit harvested at commercially mature stage were dipped in different concentrations of PUT (0.5, 1.0, and 1.5 mmolL−1), SA (1.0, 2.0, and 3.0 mmolL−1), and control (0.0 mmolL-1) for 15 minutes and stored in cold room (13 ± 1°C, 90 ± 5% RH). Evaluation of peel color (L*, a*, b*), total chlorophyll content (TCC), TSS, TA, physiological weight loss (PWL), visual quality, and decay incidence were carried out at 0 day (before treatment) and at 14, 28, 42–56 days of storage. Out of two reagents examined, PUT showed promising effect compared to SA on maintaining quality and extending the postharvest life of lime cv. Local during cold storage (13 ± 1°C, 90 ± 5% RH). The lowest dose of PUT (0.5 mmolL−1) and the middle dose of SA (2 mmolL−1) effectively suppressed the degradation of peel color, retarded the rate of deterioration of TSS and TCC while reducing the rate of increase in PWL. The lowest concentrations of both PUT (0.5 mmolL−1) and SA (1.0 mmolL−1) exhibited higher efficacy in preventing the deterioration of TA. In conclusion, exogenous treatment of PUT at the dose of 0.5 mmolL−1or SA at the concentration of 2 mmolL−1for 15 min could be recommended as an effective tool for maintaining quality and extending the shelf life of lime cv. Local.

Influence of foliar application with putrescine, salicylic, and ascorbic acid on the productivity and physical and chemical fruit properties of Picual olive trees

Background and objectiveOlive tree is very popular in the Mediterranean area because of its fruits and oil yields. Both of them are worldwide known by their beneficial health properties. Salicylic acid is naturally occurring as phenolic compound and endogenously synthesized as signaling molecule in plants and influences various physiological and biochemical functions in plants. Ascorbic acid is an antioxidant molecule and a key substrate for the detoxification of ROS. Putrescine participates in several processes of plant growth and development. Putrescine participates in several processes of plant growth and development. Therefore, the objective of this study is to determine the best concentrations of these substances to improve olive fruits yield and its chemical and physical properties.Materials and methodsThe field experiment was conducted during two seasons of 2017 and 2018 on adult olive trees of Picual cv. (8 years old) in a private orchard located in Ismailia Governorate, Egypt, to study the effect of foliar application with different concentrations of putrescine, salicylic, and ascorbic, in two dates of November and December. The effect of different concentrations and dates of spray under the conditions of the saline irrigation water (4.40 ds m−1) were evaluated on the fruit yield, fruit physical characteristics and fruit chemical properties of olive trees of Picual cv.ResultsIn this study, all treatments were able to improve all studied characters compared with the control treatment in both spraying dates of November and December in both seasons, respectively. Moreover, the best yield of olive fruits in this study was recorded with the application of putrescine at 15 ppm + salicylic at 200 ppm + ascorbic at 2000 ppm in the first and second seasons, respectively.ConclusionSpraying Picual olive trees with putrescine, salicylic, and ascorbic acid in this study under the conditions of the saline irrigation water (4.40 ds m−1) was able to improve fruit yield and fruit physical and chemical properties of olive trees of Picual cv. compared with the control treatment in both spraying dates

Effect of Different Concentrations of BAP and Putrescine on Potato Microtuberization (cv. Agria)

One of the most critical stages of produced virus free potato plants is rapid and efficient in vitro microtuberization. Plant growth regulators and their concentration is important factor on potato microtuberization. This study was conducted to develop a protocol for rapid microtuber formation for potato micropropagation by different concentrations of 6-Benzylaminopurine (BAP) (0, 1 and 2 mg.l-1) and five concentrations of Putrescine (0, 20, 40, 80 and 160 mg.l-1) with 8% sucrose and 8 g.l-1 agar. Present study was conducted as a factorial experiment based on completely randomized design with three replications in tissue culture laboratory to investigate the effect of different BAP and Putrescine concentrations. Lateral buds of cv. Agria from in vitro shoots were cultured as explants. Cultures were kept in germinator with constant darkness and temperature of 17±2°C. Variance analysis showed that none of the traits were affected by different concentrations of the Putrescine other than weight of the shoots. Also, the interaction effect of PUT×BAP on shoot weight was significant. However, the effect of different levels of BAP was significantly associated with the most trait of microtuberization. In this experiment, the best concentration of BAP for microtuberization was 1 mg.l-1. Also, the appropriate Putrescine level for increasing of microtuberization number and percentage was 80 mg.l-1 but the effect of Putrescine on microtuberization number and percentage was non-significant.

Effect of putrescine and type of light in callus of Gardenia Jasminoides L. content from some effective medical compounds

The experiment was carried out in the laboratory of tissue culture of Plant Production Techniques Department, at Musaib Technical College to study the effect of different concentrations of putrescine and the type of light on the content of the Gardenia from some effective medical compounds. The experiment included two factor the first consisted of two sources of light, namely light (fluorescent), LED light (18 red: 2 blue) and the second factor, the addition of Putrescine with three concentrations (0.5, 1 and 1.5) mg.l-1. Some effective medical substances (Coumaric, Ferulic, Caffeorylquanic, Sinapic acid and Tannic) acids was measured in Callus Of Gardenia using high-performance liquid chromatography (HPLC).The results were analyzed using the statistical program Genstat and the mean was measured according to the least significant difference of LSD at the probability level of 5%. The results showed superior treatment of LED lighting in the concentration of all measured active compounds, The highest concentration of compounds (Ferulic, Caffeorylquanic and Sinapic) acids was given with a concentration of 0.5 mg.l-1. The highest concentration of compounds (Coumaric and Tannic) acids. The interaction (LED + Putrescine at 0.5) gave the highest concentration of compounds (Ferulic, Caffeorylquanic and Sinapic) in Callus of Gardenia.

The Effect of Different Concentrations of Putrescine and Indole Butyric Acid (IBA) on Rooting of Semi-Hardwood Cuttings of GN15 Hybrid Rootstocks

The Effect of Different Concentrations of Putrescine and Indole Butyric Acid (IBA) on Rooting of Semi-Hardwood Cuttings of GN15 Hybrid Rootstocks

In vitro regeneration of double haploid line of African marigold (Tagetes erecta) derived from ovule culture using non-axillary explants

An efficient protocol has been developed for in vitro regeneration of double haploid line of African marigold variety Local Orange derived through ovule culture. Maximum survival (85%) of leaf explant was found in the treatment comprising of Bavistin (0.2%), Ridomil (0.2%) and 8-HQC (200 ppm). The surface sterilization treatment of explants with mercuric chloride (0.1%) for 3 minutes resulted in maximum survival (88.33%) and minimum contamination (18.33%). Three different portions of leaf explant (Tip, middle and basal) were used for regeneration. The treatment comprising MS medium supplemented with BAP (0.5 mg/l) and NAA (0.25 mg/l) resulted in maximum percent regeneration (86.25), lowest number of days taken for callus initiation (3.05), minimum number of days for shoot regeneration (13.25), maximum number of micro shoots per explant (3.50), minimum number of days to reach the stage of sub culturing (5.75) with basal portion of leaf explant. Among the different explants, basal portion of the leaf was found as the best explant for maximum regeneration. The basal portion of the leaf explant was further treated with best regeneration treatment, i. e. BAP (0.5 mg/l) and NAA (0.25 mg/l) along with different concentrations of putrescine and it was observed that maximum percent regeneration (89.83%), minimum number of days for shoot regeneration (13.50), maximum number of micro shoots per explant (6.25) and minimum number of days to reach the stage of subculturing (5.75) were found in the treatment combination of BAP (0.5 mg/l), NAA (0.25 mg/l) and Putrescine (50 mg/l).

Enhancement of microspore embryogenesis induction and plantlet regeneration of sweet pepper (Capsicum annuum L.) using putrescine and ascorbic acid.

Production of doubled haploid (DH) plants is an efficient tool in genetic and plant breeding programs; however, sweet pepper (Capsicum annuum L.) is recalcitrant to microspore embryogenesis and DH production. Trying to break the barrier of DH production, three independent experiments were conducted on microspore embryogenesis of sweet pepper. In the first experiment, the effect of cold (4°C) and heat (32°C) pretreatments were investigated on microspore embryogenesis of three genotypes of sweet pepper including "Inspiration F1," "Maratus F1," and "Magno F1" cultivars in a factorial design with three replications. Heat shock (32°C for 7days), applied to mannitol-starved anthers of "Inspiration F1," showed higher multinuclear microspore percent, number of multicellular structures, total embryos, cotyledonary embryos, and regenerants. In the second experiment, the effect of different concentrations of putrescine (0, 0.5, 1, 2, and 5mgl-1) was evaluated on microspore embryogenesis of the three aforementioned cultivars of sweet pepper. The highest mean number of multicellular structures, cotyledonary embryos, and regenerants were achieved by applying 0.5-1mgl-1 putrescine during the mannitol starvation and heat shock (32°C) treatments of isolated microspore culture of "Inspiration F1" cultivar. Significant decrease in microspore embryogenesis efficiency was observed when high levels of putrescine (2 and 5mgl-1) were used. Microspore embryogenesis was prevented completely at 5.0mgl-1 putrescine. In the third experiment, the effect of different concentrations of ascorbic acid (0, 20, 50, 100, and 200mgl-1) was investigated and the results showed that the application of ascorbic acid (20 and 50mgl-1) during mannitol starvation and heat shock treatment (32°C) caused remarkable improvement in the number of produced cotyledonary embryos and their regeneration ability compared to control treatment. However, the application of higher levels of ascorbic acid (100 and 200mgl-1) inhibited microspore cell divisions and embryogenesis. In conclusion, the results indicated that both putrescine and ascorbic acid have significant effect on microspore embryogenesis efficiency of sweet pepper when they are used in appropriate concentrations.

Exogenous putrescine changes redox regulations and essential oil constituents in field-grown Thymus vulgaris L. under well-watered and drought stress conditions

Drought stress affects a vast range of morphological, physiological and biochemical characteristics in plants; however, exogenous application of osmotically active materials such as polyamines has been regarded as a good alternative to counter the adverse effects of various environmental stresses on plant functions. The present study investigates the response of Thymus vulgaris L. plants to different concentrations of putrescine (0, 20 and 40 mg L−1) under well-watered and drought stress conditions in a factorial experiment based on randomized complete block design with three replications during 2-year field trial. Drought stress significantly impaired the plant growth and biomass accumulation, and altered leaf water status, photosynthetic pigment contents, hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels, free proline and soluble protein contents, ROS scavenging enzymes such as superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), and ascorbate peroxidase (APX), essential oil content and chemical profiles of the essential oil compared to the respective control values. However, exogenously applied putrescine (particularly at 20 mg L−1) improved leaf water content, accumulated dry matter, reduced cell injury indices and up-regulated antioxidant enzyme activities. Moreover, stressed plants treated with the highest concentration of putrescine increased their essential oil content by 23.07% compared to non-stressed plants without putrescine application. A total of 14 compounds predominantly consisted of monoterpenes such as Thymol, Carvacrol, γ-Terpinene and p-Cymene were identified in the essential oil of the plants in both years. Percentage of the major essential oil constituents substantially enhanced under drought stress, whereas exogenous application of putrescine further improved the content of these specific volatile compounds under well-watered and stressed plants compared to the respective control. A significant negative correlation was observed between essential oil percentage and H2O2 (r0.01 = −0.928) and MDA (r0.01 = −0.947) contents in plants under drought stress. The results of this study indicated that foliar application of putrescine in proper level may act as elicitor to trigger physiological processes and induce valuable metabolites biosynthesis, which may compensate the negative impacts of drought stress on plant biomass and essential oil quality and quantity.

Putrescine induces somatic embryo development and proteomic changes in embryogenic callus of sugarcane

Somatic embryogenesis, an important biotechnological technique, has great potential for application in sugarcane breeding and micropropagation. Polyamines have been associated with the regulation of several physiological processes, including the acquisition of embryogenic competence and somatic embryogenesis. In this study, we used a proteomic approach to evaluate the effects of exogenous polyamine on sugarcane somatic embryo development to better understand this process. Embryogenic cultures were treated with different concentrations of putrescine, spermidine, and spermine. Proteomic analyses combined the shotgun method and the nanoESI-HDMSE technology. Among polyamines, 500μM putrescine gave rise to the highest number of somatic embryos; however, no differences in the amount of fresh matter were observed between polyamines and control. Differences in protein abundance profiles resulting from the effect of 500μM putrescine on sugarcane somatic embryo maturation were observed. Proteomic analyses of putrescine and control treatment showed differences in the abundances of proteins related to somatic embryogenesis, such as arabinogalactan proteins, peroxidases, heat shock proteins, glutathione s-transferases, late embryogenesis abundant proteins, and 14-3-3 proteins. These results show that putrescine and the identified proteins play important roles in protecting the cells against an in vitro stress environment, contributing to the formation of somatic embryos during the maturation treatment. Biological significanceDespite all studies with somatic embryogenesis, the molecular mechanisms controlling the process have not been completely understood. In this study, we highlighted the effects of the polyamine putrescine on somatic embryogenesis of sugarcane and the differentially abundant proteins related to somatic embryo development. We identified six groups of important stress related proteins that are involved in the adaptation of cells to the stress environment of in vitro culture and may also be part of the mechanisms associated to the somatic embryogenesis process. Therefore, our research is trying to understand the complexity of how one single somatic cell becomes a whole plant.

Effects of salicylic acid and putrescine on storability, quality attributes and antioxidant activity of plum cv. ‘Santa Rosa’

Plum fruit has a short shelf life with a rapid deterioration in quality after harvest. The primary goal of this study is to investigate and compare the effect of putrescine and salicylic acid on quality properties and antioxidant activity of plum during storage. The plum fruits (cv. 'Santa Rosa') were harvested at the mature ripe stage, and dipped in different concentrations of putrescine (1, 2, 3 and 4mmol/L) and salicylic acid (1, 2, 3 and 4mmol/L), as well as distilled water (control) for 5min. The fruits were then packed in boxes with polyethylene covers and stored at 4°C with 95% relative humidity for 25days. A factorial trial based on completely randomized block design with 4 replications was carried out. The weight loss, fruit firmness, total soluble solids, titratable acidity, pH, maturity index, ascorbic acid, total phenolics and antioxidant activity at 0, 5, 10, 15, 20 and 25days after harvest were recorded. During the storage period, the weight loss, total soluble solids, pH and maturity index increased significantly while the fruit firmness, titratable acidity, ascorbic acid, total phenolics and antioxidant activity decreased significantly (P < 0.05) for all treatments. Statistically significant differences were observed between different treatments (putrescine, salicylic acid and control) in all measured parameters. The data showed that the weight loss and softening of the plum fruits were decreased significantly by the use of putrescine and salicylic acid. Also, exogenous treatments of putrescine and salicylic acid are found to be effective in maintaining titratable acidity, ascorbic acid, total phenolics and antioxidant activity in plum fruits during storage at 4°C. It was concluded that postharvest treatment of plum fruit with putrescine and salicylic acid were effective on delaying the ripening processes and can be used commercially to extend the shelf life of plum fruit with acceptable fruit quality.

Influence of Putrescine on Enzymes of Ammonium Assimilation in Maize Seedling

The effect of different concentrations of putrescine on biochemical changes in root and shoot of six days old maize seedlings in terms of enzymes of ammonium assimilation were examined. The results revealed that glutamate dehydrogenase (GDH) activity was enhanced at lower concentration of putrescine but at higher concentration, the activity of this enzyme was declined. Glutamine synthetase (GS) activity decreased with increase in concentration of putrescine and it was highest at 1000 μm concentration. Howe ver, glutamate synthase (GOGAT) activity increased with increase in concentration of putrescine upto 100 μm in root and upto 50 μm in shoot and further increase in concentration resulted in decline of enzymatic activity. Protein and total nitrogen content increased upto 10 μm concentration of putrescine and it decreased further with increase in concentration both in root and shoot of maize seedling.

EFFECT OF POSTHARVEST PUTRESCINE APPLICATION AND CHITOSAN COATING ON MAINTAINING QUALITY OF TABLE GRAPE CV. “SHAHROUDI” DURING LONG-TERM STORAGE

The role of postharvest application of putrescine (PUT) alone or in combination with chitosan (CH) on maintaining quality of fresh table grapes (Vitis vinifera) cultivar “Shahroudi” was investigated. The clusters were dipped in an aqueous solution containing different concentrations of PUT (0, 1 and 2 mM). Following PUT treatments, some fruits were coated with 1% w/v CH. After treatment, fruits were stored at 0 ± 1C and 90 ± 5% relative humidity for 60 days and 5 additional days in evaluation room. The general appearance of rachis and berries and some physiological characters were estimated. The combination of 1 mM PUT and 1% CH reduced the weight loss, decay incidence, browning, and berry shattering and cracking. Postharvest PUT-treated berries (1 and 2 mM) exhibited higher total phenolic content, catechin, total quercetin and antioxidant activity and the lower quercetin 3-galactoside as compared with other treatments. PRACTICAL APPLICATIONS Table grape is a nonclimacteric fruit with a low physiological activity, but is subject to serious physiological disorders, water loss and fungal deterioration during postharvest handling. Stem browning and gray mold infection caused by the fungus Botrytis cinerea are the two main factors which reduce table grape postharvest quality. Recently, biologically active natural products have started to become an effective alternative to synthetic fungicides in maintaining fruit quality during storage. Chitosan coating has been reported to enhance disease resistance against many fungal diseases, when applied as either a preharvest or postharvest treatment. Polyamines (PAs) are also biological compounds with low molecular weight that are ubiquitous in living organisms. PAs have been reported as anti-senescence agents, the main effects in fruits being retarded color changes, increased fruit firmness, delayed ethylene and respiration rate emissions, induced mechanical resistance.

Effects of exogenous application of polyamines on wheat anther cultures

Androgenesis of wheat genotypes was evaluated by pretreating anthers or embryo-like structures (ELS) with polyamines. Anthers of the genotype DH were pretreated with different concentrations of putrescine, spermidine, and spermine for 1, 3, and 6 h, and those of drought-tolerant International Center for Agricultural Research in the Dry Areas (ICARDA) wheat accessions were treated for 1 and 3 h. ELS of two genotypes were also treated for 30 and 60 min with the same polyamines and evaluated for green plant regeneration. The pretreatment of anthers with polyamines enhanced the development of ELS in all genotypes. The formation of ELS varied significantly with genotype. Pretreated anthers showed that four treatments improved significantly green plant regeneration with the genotype ICR 17. However, two treatments (1 mM putrescine or spermine for 1 h) significantly improved green plant regeneration per 100 ELS of only two ICARDA genotypes. ELS treated with polyamines for 30 min were greener and formed more adventitious roots. The chloroplasts of these greener ELS examined with a transmission electron microscope had agranal to grana thylakoids, while those of the control had plastids with mostly starch globules. Although exogenous application of polyamines to anthers improved the production of ELS and green plants, the effects of putrescine, spermidine, and spermine was dependent on genotype and the duration of pretreatment of anthers with the polyamines.

Pre-storage putrescine application suppresses ethylene biosynthesis and retards fruit softening during low temperature storage in ‘Angelino’ plum

To investigate the role of putrescine (PUT) in ethylene biosynthesis and fruit softening of plum ( Prunus salicina Lindl. cv. Angelino), fruit on trees were sprayed 1 week before anticipated commercial harvest, or after harvest fruit were dipped in an aqueous solution containing different concentrations of PUT (0.0, 0.1, 1.0 and 2.0 mM), and ‘Tween 20’ (0.01%) as a surfactant. Following PUT treatments fruit were stored at 0 ± 1 °C and 90 ± 5% RH for 0, 3 and 6 weeks. Ethylene production, activities of 1-aminocyclopropane-1-carboxylic acid synthase (ACS) and 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) enzymes, and 1-aminocyclopropane-1-carboxylic acid (ACC) content, fruit firmness and activities of fruit softening enzymes including exo-polygalacturonase ( exo-PG), endo-polygalacturonase ( endo-PG), pectin esterase (PE) and endo-1,4-β- d-glucanase were estimated after 0, 3 and 6 weeks storage. Pre- and postharvest PUT application reduced ethylene production after 3 and 6 weeks of storage as compared to untreated fruit. Preharvest spray application of higher PUT concentrations substantially reduced ethylene production compared to lower PUT concentrations and postharvest PUT treatments. Activities of ACS enzymes and ACC contents during storage decreased with increased concentration of PUT applied irrespective of the methods of its application, both in skin and pulp tissues. Preharvest PUT-sprayed fruit exhibited lower ACO activities than postharvest PUT-treated skin and pulp tissues. The preharvest spray application of higher concentrations of PUT (2.0 and 1.0) significantly reduced the activities of fruit softening enzymes ( exo-PG, endo-PG, PE and EGase) in skin and pulp tissues during storage. In conclusion, pre-storage application of PUT retarded plum fruit softening during low temperature storage through suppressed ethylene biosynthesis and reduced activities of fruit softening enzymes such as PE, EGase, exo and endo-PG in skin and pulp tissues.

Effect of exogenous putrescine on post-harvest life of strawberry ( Fragaria ananassa Duch.) fruit, cultivar Selva

Effect of different concentrations of putrescine on post-harvest life of strawberry ( Fragaria ananassa Duch.) fruit, cultivar Selva at 5 °C was studied. Fruits were immerged in 0.3, 0.5, 1 and 2 mM putrescine as well as distilled water (control) for 5 min, then transferred into the fridge (5 °C) together with untreated fruits (dry treatment). The rate of weight loss, ethylene production, flesh firmness, soluble solids content, titratable acidity and pH of fruits were determined 5, 9 and 13 days after the beginning of storage. Flesh firmness, appearance, color change and taste of fruits were also determined in the same intervals using a taste panel. Storage life of the strawberry fruits was significantly increased by the use of putrescine, so that the untreated and control fruits had 6 and 8 days storage life, respectively, while the immerged fruits in 1 and 2 mM putrescine were still suitable to be exposed in the market 12 and 14 days after the beginning of storage, respectively. No significant weight losses were observed in treated fruits compared to controls and dry treatment at all determination times. Ethylene production was decreased significantly by the use of putrescine. Untreated fruits (dry treatment) had the highest rate of ethylene production and the lowest rate was occurred in 2 mM putrescine treatment at all determination times (5, 9 and 13 days after the beginning of storage). The use of putrescine also prevented the softening of fruit flesh during the storage and kept their firmness, so that, the 2 mM putrescine treatment caused the highest fruit firmness at all determination times. Distilled water treatment (control) had the lowest fruit firmness 5 and 9 days after storage, while this occurred for the dry treatment 13 days after storage. Soluble solids content, pH and titratable acidity of the fruits were not significantly affected by the use of putrescine, but the highest and lowest rate of titratable acidity were related to the 2 mM putrescine and dry treatment, respectively, at the three determination times. Overall, the quality of fruits was improved by the use of 2 mM putrescine in terms of properties evaluated by the taste panel.

EXOGENOUS APPLICATION OF PUTRESCINE AFFECTS MANGO FRUIT QUALITY AND SHELF LIFE

Short shelf life of mango fruit limits its export to distant markets. The effects of pre and postharvest applications of putrescine on fruit ripening, quality and shelf life of 'Kensington Pride' mango were investigated. An aqueous solution of different concentrations of putrescine (0, 0.5, 1.0, or 2.0 mmol.L-1) containing the surfactant 'Tween-20' (0.01%) were applied as preharvest spray onto trees 7 days prior to harvest and postharvest fruit dip treatments for 6 minutes. One lot of the treated and control fruit was allowed to ripen at room temperature (21 plus / minus 1 deg C) while the second batch was stored at 13 deg C (85% RH) for 20 days. Fruit ripening at ambient temperature revealed that putrescine treatments significantly reduced ethylene production and response was more pronounced in the postharvest dip application than the preharvest spray. Ethylene production decreased as the concentration of applied putrescine increased. Pre and postharvest application of putrescine increased fruit firmness and decreased sugars, compared with control. Both pre and postharvest application also retarded fruit colour development. After 20 days storage, preharvest-treated fruit exhibited higher firmness, TSS and lower fruit rot whilst acidity, total and non-reducing sugars were reduced in fruit treated with both methods, compared with control. In conclusion, preharvest putrescine spray was more effective than postharvest dip. Putrescine treatment (1 mmol.L-1) was effective in delaying fruit ripening at ambient temperatures, whilst 2 mmol.L-1 extended the shelf life and improved fruit quality of 'Kensington Pride' mango.