The Action of Kinetin in Improving the Water Balance and Delaying Senescence Processes of Cut Rose Flowers

Mayak, Shimon; Halevy, A. H.

doi:10.1111/j.1399-3054.1974.tb03146.x

Cited by 46 publications

(18 citation statements)

References 20 publications

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“…They may operate by maintaining membrane permeabilities (7), water balance (14), and/or protein and nucleic acid metabolism (17). The presence of optimal concentrations of cytokinins may also increase longevity of flowers by reducing their ethylene production and responsiveness.…”

Section: Resultsmentioning

confidence: 99%

“…They concluded that processes other than respiration mediate the cytokinin retardation of senescence. Mayak and Halevy (14) have shown that kinetin increases net water uptake of expanding rose petals and delays wilting of petals especially when flowers are subjected to heat (28 C) and low relative humidity (40-50%). Kinetin had no effect on protein content of rose petals under these stressful conditions, but kinetin retarded the increase in RNase activity normally seen in rose flowers at the onset of senescence.…”

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confidence: 99%

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Role of Cytokinins in Carnation Flower Senescence

Eisinger

1977

Plant Physiol.

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Stem and leaf tissues of carnation (Dianthus caryophyllus) plants appear to contain a natrl antisenescence fator since removal of most of these tissues from cut camation flowers hastened their senescence.However, kinetin (5-10 jg/ml) sign ty delayed senescence of flowers with stem and leaf tissues removed. In addition, the life span of cut flowers with intac (30-cm) stems was increased with kinetin treatment.Peak ethylene production by presenescent flowers was reduced 55% or more with kinetin treatment and was delayed by 1 day. Kinetin-treated flowers were less responsive to applied ethylene (100 gd/l for 3 hours) than untreated flowers. Possible natural roles of cytokinins in carnation flower senescence are discussed.Cytokinins are known to defer leaf senescence (18) and improve the keeping qualities of cut carnation (6, 11) and rose flowers (12). MacLean and Dedolph (11) reported a decrease in the respiration rate of cytokinin-treated flowers and proposed that cytokinins increase flower longevity as a result of this reduction in respiration. However, Heide and Oydvin (6) found only small and inconsistent effects of cytokinins on the respiration rate of cut carnation flowers. They concluded that processes other than respiration mediate the cytokinin retardation of senescence. Mayak and Halevy (14) have shown that kinetin increases net water uptake of expanding rose petals and delays wilting of petals especially when flowers are subjected to heat (28 C) and low relative humidity (40-50%). Kinetin had no effect on protein content of rose petals under these stressful conditions, but kinetin retarded the increase in RNase activity normally seen in rose flowers at the onset of senescence. Kinetin is proposed to increase rose flower longevity by improving water balance and delaying senescence processes.Ethylene gas has been proposed as the natural regulator of flower senescence (1,16 Ethylene production by flowers was measured by placing six flowers with 3-cm stems in a 9-liter vacuum desiccator whose volume was reduced to 6.5 liters with inert materials. The atmosphere was sampled after 3 hr and ethylene was determined using a flame ionization gas chromatograph (Perkin-Elmer model 800) with a (90 x 0.5 cm) Porapak S (100-120 mesh, Waters Associates, Milford, Mass.) column. The desiccators remained open during the 21-hr interval between daily readings. RESULTSRemoval of the major portion of the stem (with leaves) of cut carnation flowers hastened the onset of senescence. Flowers with 3-cm stems (leafless) had an average life span of 13 + 2 days compared to an average life span of 17 ± 2 days for 30-cm stemmed control flowers. Removal of only the leaves from flowers with 30-cm stems reduced the life span of the flowers but to a lesser extent. However, 10 ,Lg/ml kinetin significantly delayed the onset of senescence of both short and long stemmed flowers. The life span of 3-cm stemmed flowers was increased to 20 ± 2 days and leafless, 30-cm stemmed flowers were restored to a similar level. Equivalent kinetin tre...

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Role of Cytokinins in Carnation Flower Senescence

Eisinger

1977

Plant Physiol.

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“…A change in the hormonal balance during the senescence of flowers had been described. The level of cytokinins is reduced while ethyiene and ABA will increase (6,9,10,12). Correspondingly, it has been demonstrated that application of ABA will enhance senescence (7,10).…”

Section: Introductionmentioning

confidence: 99%

Combined Effects of Abscisic Acid and Sucrose on Growth and Senescence of Rose Flowers

Borochov

Mayak

Halevy

1976

Physiologia Plantarum

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The effects of sucrose and abscisic acid (ABA) and their interaction on development and senescence of petals were studied with leafless roses cultivar Super Star. Sucrose and ABA had opposing effects on the cut flowers. Sucrose retarded and ABA promoted processes associated with senescence: wilting, increase in pH, “blueing” and decrease in protein content of petals. These opposing effects are mutually antagonized when both chemicals are applied. ABA applied to flowers cut at the bud stage, promoted the rate of petal growth (but not their final size), increased respiration and caused a decrease in sucrose and an increase in level of reducing sugars. It is suggested that one way by which ABA accelerates senescence of cut roses is by promoting petal growth and respiration, thus decreasing the carbohydrate level in the petals and triggering the chain of metabolic processes leading to aging.

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“…Rose petals have no stomata (11,20). In contrast to most other studies with cut roses, we conducted the present investigation with flowers whose leaves were removed.…”

Section: Resultsmentioning

confidence: 94%

Abscisic Acid Content of Senescing Petals on Cut Rose Flowers As Affected by Sucrose and Water Stress

Borohov

Tirosh²,

Halevy³

1976

Plant Physiol.

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Leafless cut Superstar roses (Rosa hyb.) were kept in a 1% sucrose solution. During the first few days of treatment, the abscisic acid content and the water deficit in the petals was higher in treated flowers than in controls kept in water. Later and up (3,7,10). Sucrose is the main transport form of the products of photosynthesis. When flowers are cut, they are severed from their sucrose supply and this no doubt is one of the reasons for imperfect development and the shorter life span of the cut flower (17). Sucrose supplied exogenously, promotes normal development of the cut flower, lengthens its life span, diminishes the change in petal color, and reduces proteolytic breakdown (1,3,16 flower stems were graded to a uniform length of 40 cm and before placing in 500-ml vases containing the treatment solutions, all leaves were removed from the stem. The flowers were kept under controlled conditions of 20 t 1 C, 55 t 10% relative humidity, and continuous illumination from cool white fluorescent light at a light energy flux density of 650 MAw/cm2. The base of the flower stalk was recut every other day and the solutions in the vases was brought up to a volume of 500 ml. The environment was not changed in experiments involving water stress, but flowers were removed from the solutions for specified periods of times (Fig. 3, Table I). At the end of the stress treatment the stems were recut. Some of the flowers which had been subjected to water stress conditions for 4 hr were given a recovery treatment. This consisted of wrapping the flower bud with wet blotting paper after the flower had been returned to its vase containing the treatment solution. This treatment raised the humidity around the flower to 90 to 100%. All treatment solutions contained 300 ,ug/ml A12(SO4)3 16 H20 to prevent development of bacteria.Extraction and Determination of ABA in Petals. Extraction, separation, and identification methods were adapted from those described in previous reports (10,15,18,19). Details of certain changes follow. Extraction and Purification. Each sample consisted of all the petals from five flowers. Samples were weighed (12 to 30 g fresh weight) and blended in 80% methanol (10 ml/g) for 2 min in a Waring Blendor. The resulting suspension was shaken for 18 hr at 4 C in the dark. After filtering, the solids were further extracted by shaking in the dark for 1 hr at 4 C with 3 ml/g 100% methanol. The combined methanol fractions were evaporated down to the aqueous phase at 38 C under vacuum. After centrifugation for 20 min at 500g, the supernatant was brought to pH 8.3 with NH40H and washed three times with methylene chloride (v/v) which was then discarded. After acidifying the aqueous phase to pH 3 with HCI, it was washed six times with methylene chloride (v/v), after which the aqueous phase was discarded. The methylene chloride fraction was evaporated to dryness at 38 C under vacuum.Preparative TLC. Samples were dissolved in 1 ml methylene chloride and these were loaded as a band on glass plates (20 x 20 cm) coated w...

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The Action of Kinetin in Improving the Water Balance and Delaying Senescence Processes of Cut Rose Flowers

Cited by 46 publications

References 20 publications

Role of Cytokinins in Carnation Flower Senescence

Role of Cytokinins in Carnation Flower Senescence

Combined Effects of Abscisic Acid and Sucrose on Growth and Senescence of Rose Flowers

Abscisic Acid Content of Senescing Petals on Cut Rose Flowers As Affected by Sucrose and Water Stress

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