Senescence Of Cut Carnation Flowers Research Articles

Nano Silver and melatonin effectively delay the senescence of cut carnation flowers under simulated vibrational stress

ABSTRACT Carnation (Dianthus caryophyllus L.) holds great significance as a cut flower, and its vase life plays a crucial role in determining its quality and market appeal. However, the extended transportation distances from the production location to consumer markets can have an unfavourable impact on the vase life and overall quality of cut flowers. The first experiment demonstrated that exposing cut carnation flowers to simulated vibrational stress (SVS) led to a decline in vase life and overall quality. Notably, the application of Nano Silver (NS; 25 and 50 μM) and melatonin (MT; 100 and 200 μM) into the holding solution proved effective in counteracting these negative effects, and extended the vase life by promoting cut flower water relations. In the second experiment, the optimal concentrations of NS and MT into the holding solution (25 and 100 μM, respectively) effectively reduced chlorophyll degradation, electrolyte leakage, and lipid peroxidation by enhancing the activity of catalase and peroxidase enzymes. As a result, it appears that the application of NS and MT in the holding solution has successfully prolonged vase life by both improving water balance and boosting antioxidant activity, while mitigating the negative effects of SVS.

Hydrogen Nanobubble Water Delays Petal Senescence and Prolongs the Vase Life of Cut Carnation (Dianthus caryophyllus L.) Flowers.

The short vase life of cut flowers limits their commercial value. To ameliorate this practical problem, this study investigated the effect of hydrogen nanobubble water (HNW) on delaying senescence of cut carnation flowers (Dianthus caryophyllus L.). It was observed that HNW had properties of higher concentration and residence time for the dissolved hydrogen gas in comparison with conventional hydrogen-rich water (HRW). Meanwhile, application of 5% HNW significantly prolonged the vase life of cut carnation flowers compared with distilled water, other doses of HNW (including 1%, 10%, and 50%), and 10% HRW, which corresponded with the alleviation of fresh weight and water content loss, increased electrolyte leakage, oxidative damage, and cell death in petals. Further study showed that the increasing trend with respect to the activities of nucleases (including DNase and RNase) and protease during vase life period was inhibited by 5% HNW. The results indicated that HNW delayed petal senescence of cut carnation flowers through reducing reactive oxygen species accumulation and initial activities of senescence-associated enzymes. These findings may provide a basic framework for the application of HNW for postharvest preservation of agricultural products.

Comparison of petal senescence between cut and intact carnation flowers using potted plants

The phytohormone ethylene is known to play a crucial role in promoting petal senescence in cut carnation flowers. In most previous studies in carnation, petal senescence was analyzed in cut flowers, and knowledge of petal senescence in intact flowers is limited. In this study, we compared changes in sugar level, ethylene production and expression of senescence-associated genes during petal senescence in cut and intact flowers using potted carnations (Dianthus caryophyllus L. cv California Mahalo). Flower longevity was significantly shorter in cut flowers than in intact flowers. Both cut and intact flowers showed inward rolling of petals and an increase in ethylene production at the end of their floral life; however, the timing of increase in ethylene production was clearly accelerated in cut flowers. Glucose and fructose levels in the petals of cut flowers rapidly decreased from the full-opening stage, while these levels remained relatively high in intact flowers. The accelerated induction of genes for 1-aminocyclopropane-1-carboxylate (ACC) synthase (DcACS1) and ACC oxidase (DcACO1) in cut flowers corresponded with ethylene production. The transcript level of DcEIL1/2, a homolog of EIN3, which is a key component in ethylene signaling, rapidly decreased in senescing petals of cut flowers, while it remained relatively high until the end of floral life in intact flowers. We isolated a homolog of autophagy-related gene 8 (DcATG8a), which is an essential gene for autophagy, and a gene for hexokinase (DcHXK1), which is known as a glucose sensor, from carnation flowers. Increasing transcript level of DcATG8a in senescing petals corresponded with ethylene production in both intact and cut flowers. The transcript level of DcHXK1 gradually decreased over time in both cut and intact flowers, but to a lesser extent in intact flowers. These results suggest that petal senescence in cut flowers is hastened by accelerated ethylene production, which is likely due to a rapid decrease in sugar content. Our data on hexokinase may also suggest the involvement of a sugar sensor in the regulation of petal senescence.

The synthesis of novel oxime ethers and their effects on the senescence of cut carnation flowers

The high levels of ethylene in plants are involved in a range of harmful effects, such as the senescence of plants and the rotting of fruits. A series of novel oxime ethers were synthesized to counteract the ethylene effects. Their structures were characterized by IR, MS, and 1H NMR, and their effects on the senescence of cut carnation flowers were investigated. The results show that all of the target compounds extended the vase life of cut carnation, especially for compound 3i, which prolonged the vase life of cut carnation flowers to about 11 days, nearly 75% longer vase life compared to the control groups. Most of them were more effective than AgNO3 and aminooxyacetic acid.

Role of Salicylic Acid in Decreases of Membrane Senescence in Cut Carnation Flowers

Cut flowers of carnation were treated with Salicylic acid (0,1.5, 3 mM) and sucrose (0, 3%).The effects of Salicylic acid on the ACC-oxidase activity, bacteria populations in vase flower preservative solution, anthocyanin leakage, Membrane stability, malondialdehyde and ACCoxidase activity of cut flowers of carnations (Dianthus caryophyllus L. cv.White) were investigated. The experimental results showed that SA treatment cause descrease MDA content and ACC-oxidase activity, reduced the membrane permeability and peroxidation of lipids.also, Results showed that The best treatment involved 1.5 mM SA+ sucrose 3% . The vase solution containing 1.5 mM Salicylic acid + sucrose 3% significantly descreased MDA content, ACCoxidase activity and bacteria populations in vase flower preservative solution and increased the vase life and membrane stability of carnation cut flower compared to the control. Results suggested that Salicylic acid increases membrane stability by descrease MDA content and ACC-oxidaseactivity, bacteria populations in vase flower preservative solution of the carnation cut flowers.

CHANGES IN WATER DISTRIBUTION DURING SENESCENCE IN CUT CARNATION FLOWERS

Neutron radiographic methods are suitable for obtaining images of water distribution in intact plants. When a neutron beam irradiates a plant sample, the number of neutrons penetrating the sample decreases with the number of hydrogen atoms in the sample. Generally, plants contain more than 80% water, so a neutron image of a plant is approximately equivalent to its water distribution. In this study, the senescence of cut carnation flowers was observed using thermal neutron (TN) radiography and very cold neutron (VCN) radiography. A CCD-cooled camera intermittently photographed neutron images during neutron irradiation. To evaluate the advancement of senescence, carbon dioxide production from a flower placed in a gas-tight container was measured using a CO2 gas sensor. The gas-tight container had aluminum windows to allow better penetration of the neutron beam, and the sample was placed behind that window. Exogenous ethylene was added in order to force senescence. A highly parallel TN beam provided high-resolution neutron images, and detailed images of the carnation ovary were obtained. VCN neutron images provided high-contrast images of water content due to the low energy of the neutron beam. From the neutron images obtained, petal wilting and dehydration, and shrinkage of the whole flower were observed. The decrease in water rate was calculated from the part of the sample in which the petal density was high. The change in the water rate corresponded with the change in respiration rate (climacteric).

Preservative solutions containing boric acid delay senescence of carnation flowers

We investigated the effect of a preservative solution containing boric acid on the senescence of cut carnation flowers (Dianthus caryophyllus L. cv. Master). A 24-h pulse treatment with the preservative solution containing 50, 75 or 100 mM boric acid or continuous treatment with 1 mM boric acid resulted in strong inhibition of the climacteric ethylene production. Both the pulse and continuous treatments significantly increased flower longevity. Free and conjugated 1-aminocyclopropane-1-carboxylic acid (ACC) and ACC oxidase activity increased in carnation petals during senescence, although significantly less in boric acid-treated carnations than in control flowers. The levels of putrescine increased as senescence progressed in both control and boric acid-treated carnations and an increase in spermidine levels was higher in treated carnations. Abscisic acid levels in petals also increased during senescence, but much less in boric acid-treated carnations. It is concluded that boric acid prevents the early rise in ethylene production and considerably improves carnation vase life.

Effects of hypoxia on respiration and the onset of senescence in cut carnation flowers (Dianthus caryophyllus L.)

Abstract Oxygen concentrations ranging between 1.62 and 5.01 kPa O2 reduced the rate of CO2 evolution in cut carnation flowers (Dianthus caryophyllus L.) and, more importantly, delayed the onset of senescence. The suppressive effects of low O2 on respiration could not be ascribed to the restriction of mitochondrial terminal oxidases. An O2 concentration of 2.02 kPa totally suppressed the onset of the climacteric rise in CO2 evolution and increased the vase life of flowers twofold over that of flowers treated with STS, indicating that the retarding effects of hypoxia on the onset of senescence transcend its inhibitory effects on the action of C2H4. Hypoxia diminished the effects of exogenously applied C2H4 on the rate of CO2 evolution and appeared to retard the rate at which the usual morphological symptoms associated with petal senescence occurred. Rapid wilting, concomitant with the climacteric, was a facet of C2H4 action and coincided with a decrease in water uptake. The latter could not be ascribed to the obstruction of vascular bundles but rather to the inability of petals to absorb water. It is suggested that the sudden increase in water loss may be the result of an C2H4-induced increase in hydraulic conductivity of the petals.

Effects of spermine on ethylene biosynthesis in cut carnation ( Dianthus caryophyllus L) flowers during senescence

To investigate the relationship between polyamine and ethylene during senescence of cut carnation (Dianthus caryophyllus L.) flowers, we studied the effects of spermine on ethylene biosynthesis. Spermine delayed the senescence of cut carnation flowers and reduced ethylene production, endogenous 1-aminocy-clopropane-l-carboxylic acid (ACQ content, and the activities and transcript amounts of ACC synthase and ACC oxidase in petals. Methylglyoxal bis-(guanylhydrazone) (MGBG), an inhibitor of polyamine biosynthesis, elevated ethylene production, increased activities and amounts of transcripts for ACC synthase and ACC oxidase, and shifted the climacteric pattern of ethylene production ahead by 1 day. However, endogenous ACC content was not increased in the petals of MGBG-treated flowers because of the high activity of ACC oxidase. Spermine also inhibited MGBG-induced ethylene production by decreasing the activities and amounts of transcripts for ACC synthase and ACC oxidase. The accumulation of transcripts for ACC synthase and ACC oxidase in MGBG-treated and in climacteric control petals was correlated with the increase of these enzyme activities. By comparing ethylene production with the changes of endogenous polyamine levels from control and MGBG- or spermine-treated petals during the entire incubation period, it was suggested that endogenous polyamines possibly suppress ethylene production.

Toward a Comprehensive Model for Lipid Peroxidation in Plant Tissue Disorders

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Effects of novel oxime ether derivatives of aminooxyacetic acid on ethylene formation in leaves of oilseed rape and barley and on carnation flower senescence

New derivatives of aminooxyacetic acid were tested for their ability to inhibit ethylene formation in higher plants. Treatments with {[(isopropylidene)-aminojoxy}-acetic acid-2-(methoxy)-2-oxoethyl ester, {[(isopropylidene)-aminojoxy}-acetic acid-2-(hexyloxy)-2-oxoethyl ester or {[(cyclohexylidene)-amino]oxy}-acetic acid-2-(isopropyloxy)-2-oxoethyl ester reduced ethylene evolution by leaf discs of oilseed rape and drought-stressed barley leaves. The new compounds delayed senescence of cut carnation flowers. The endogenous levels of 1-aminocyclopropane-1-carboxylic acid (ACC) and its N-malonyl conjugate were also reduced in the leaf discs of oilseed rape. This suggests that a step in the biosynthesis of ethylene, prior to the formation of ACC, is inhibited by these new compounds. A lag phase in response suggests that these compounds have to be activated most likely by the production of metabolites with a free aminooxy group.

Inhibitory Effect of Coronamic Acid Derivatives on Senescence in Cut Carnation Flowers

(+)-(1R,2S)-Allocoronamic acid, (−)-(1S,2R)-allocoronamic acid, and their racemate showed an inhibitory effect on senesence in cut carnation flowers. This antisenescent activity was based on the inhibition of endogenous ethylene formation catalyzed by an ethylene-forming enzyme.

Effect of gibberellic acid on carnation flower senescence: evidence that the delay of carnation flower senescence by gibberellic acid depends on the stage of flower development

Gibberellic acid at concentrations of 10−5 M and 10−4 M delayed the senescence of cut carnation flowers, when applied continuously via the stem, to flowers between the closed brush and fully open stages of development. Older flowers with reflexed petals were unresponsive. Treatment with paclobutrazol, an inhibitor of GA biosynthesis, prevented tight buds from opening fully, reduced the longevity of partially open flowers, but was ineffective when applied continuously to fully open flowers. Gibberellic acid-treated flowers did not show simultaneous petal inrolling, a known indicator of senescence, and the time to complete petal drying was extended. Gibberellic acid modified the climacteric ethylene rise in a manner consistent with the extension of longevity. These results provide evidence for a correlative role of gibberellins in flower development.

Effects of vase-water bacteria on the senescence of cut carnation flowers

Abstract Cut flowering carnation stems (Dianthus caryophyllus L. cvs. Scania and White Sim) were held in water for 7 days at 20°C, after which a low hydraulic conductance and a high number of bacteria were found in the basal 5-cm stem segment. This suggested that bacteria may play a role in determining flower longevity. When taking special precautions, it was possible to keep flowering stems sterile until flower senescence. Petal wilting in the sterile stems occurred at thesame time as in non-sterile controls. Inclusion of antibacterial chemicals in the water also prevented accumulation of bacteria in the solution and in flower stems, but had no effect on flower longevity. Inclusion of bacteria, originating from the vase water of carnation flowers, in vase water at a number that is normally reached after 7 days (107 cfu ml−1) did not significantly hasten flower senescence. It is concluded that the bacterial population developing in the stems of cut carnation flowers during vase life leads to vascular occlusion but this apparently has little effect on flower longevity.

Effect of Gynoecium Excision on Auxin-mediated Promotion of Petal Senescence in Cut Carnation Flowers

Summary Uptake of moderate concentrations of auxin results in promotion of ethylene synthesis and petal senescence in cut carnation flowers. Within a particular concentration range of auxin, removal of gynoecium at harvest results in suppression of auxin-promoted ethylene synthesis and petal senescence. Since excision of only the styles causes partial suppression of the auxin effect, the ovary is probably the major site of auxin action resulting in petal senescence.

Molecular Species Specificity of Phospholipid Breakdown in Microsomal Membranes of Senescing Carnation Flowers

During senescence of cut carnation flowers, there is extensive breakdown of microsomal phospholipid. This is attributable, at least in part, to lipolytic activity associated directly with the microsomal membranes. Evidence indicating that one or more of the lipid-degrading enzymes in these membranes preferentially degrade phospholipid molecular species containing two diunsaturated acyl chains or at least one polyunsaturated acyl chain has been obtained by using radiolabeled phosphatidylcholine substrates. 16:0(*)/16:0(*), 16:0/18:2(*), and 18:1(*)/18:1(*) phosphatidylcholine were degraded only minimally over a 3 hour period by microsomes isolated from senescing flowers. By contrast, [U-(14)C]phosphatidylcholine, which comprises various molecular species including those containing polyunsaturated acyl chains, and 18:0/20:4(*) phosphatidylcholine were extensively degraded. Under identical conditions, but in the absence of added radiolabeled substrate, endogenous 18:2/18:2, 18:1/18:3, and 18:2/18:3 phosphatidylcholine were selectively depleted from the membranes. During natural senescence of the flowers, there was a sharp decline in microsomal 16:0/18:1 and 18:1/18:2 phosphatidylcholine, whereas molecular species containing two diunsaturated acyl chains or at least one polyunsaturated acyl chain remained unchanged or decreased only slightly. The data have been interpreted as indicating that provision of particular molecular species susceptible to lipase attack is a prerequisite to phospholipid catabolism in senescing membranes.

Senescence in cut carnation flowers: Temporal and physiological relationships among water status, ethylene, abscisic acid and membrane permeability

Changes in water status, membrane permeability, ethylene production and levels of abscisic acid (ABA) were measured during senescence of cut carnation flowers (Dianthus caryophyllus L. cv. White Sim) in order to clarify the temporal sequence of physiological events during this post‐harvest period. Ethylene production and ABA content of the petal tissue rose essentially in parallel during natural senescence and after treatment of young flowers with exogenous ethylene, indicating that their syntheses are not widely separated in time. However, solute leakage, reflecting membrane deterioration, was apparent well before the natural rise in ethylene and ABA had begun. In addition, there were marked changes in water status of the tissue, including losses in water potential (ψw), and turgor (ψp), that preceded the rise in ABA and ethylene. As senescence progressed, ψw continued to decline, but ψp returned to normal levels. These temporal relationships were less well resolved when senescence of young flowers was induced by treatment with ethylene, presumably because the time‐scale had been shortened. Thus changes in membrane permeability and an associated water stress in petal tissue appear to be earlier symptoms of flower senescence than the rises in ABA or ethylene. These observations support the contention that the climacteric‐like rise in ethylene production is not the initial or primary event of senescence and that the rise in ABA titre may simply be a response to changes in water status.

Regulation of Ethylene Biosynthesis and Action in Cut Carnation Flower Senescence by Cytokinins

Abstract Cytokinins delay the onset of senescence in cut carnation flowers (Dianthus caryophyllus) by affecting the biosynthesis and action of ethylene in the tissue. The onset of senescence is marked by an increase in ethylene sensitivity and production by the tissue. A characteristic rise in 1-aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor of ethylene, accompanies the initial stages, but the greatest increases in ACC are associated with the decline in ethylene production during the later stages of senescence. Cytokinins delay the onset of senescence and reduce ethylene sensitivity and production. Benzyladenine (BA), a cytokinin, prevents the rise in endogenous ACC levels and reduces the capacity of the tissue to convert ACC to ethylene. The effects of other anti-senescence agents, aminoethoxy vinylglycine (AVG), silver ions and cobalt ions, are compared with those of BA on ethylene sensitivity and production. The mechanism of action of BA in the delay in flower senescence is discussed.

Role of Ethylene in Distribution of Assimilates in Cut Carnations

Distribution patterns of assimilates were studied during senescence in cut carnation flowers pretreated with water or with the flower preservative and anti-ethylene agent, silver thiosulphate. Within the first 5 days after harvest a substantial translocation of assimilates to petals was observed, which ended simultaneously with wilting of the petals. Silver thiosulphate pretreatment prevented wilting and caused a continuous translocation towards the petals. Such a pretreatment caused a decrease in the translocation of assimilates to the pistil, which in water controls continued to accumulate radioactive assimilates during post-harvest life. The interaction between ethylene and assimilate translocation in cut carnation flowers is discussed.

Polysomal Population in Relation to Ethylene Production and the Senescence of Cut Carnation Flowers and Floral Parts

Abstract Ribosomes were isolated from styles, receptacles, and petals of cut ‘White Sim’ carnation flowers (Dianthus caryophyllus L.) during flower senescence. In all flower parts the percentage of polysomes decreased for a few days after cutting and then increased coincident with the surge of ethylene production in the final stages of floral senescence. Changes in the polysomal population in petals excised from the same flower at progressive stages of its senescence were identical with those obtained from petals excised from different flowers at similar stages of senescence. The polysomal data confirm the occurrence of increased protein synthesis coincident with ethylene production and the senescence of cut carnation flowers.