Chrysanthemum Cut Flowers Research Articles

PROCESSES AND XYLEM ANATOMICAL PROPERTIES INVOLVED IN REHYDRATION DYNAMICS OF CUT FLOWERS

In cut flowers, which are harvested in air and transported dry, all cut xylem vessels in the basal part of the stem contain air instead of water. These air-emboli initially block water transport at the start of vase life, but usually (partly) disappear during the first hours of vase life, resulting in rehydration of the flower. However, in some cases flowers are not able to sufficiently remove these air blockages, resulting in a poor water status expressed by wilting. Differences in rehydration ability are present between cultivars, but also between different lots of flowers within one cultivar as result of growing conditions. Using chrysanthemum cut flowers, investigations are focussed on the dynamics of the flower water status during the first hours of vase life after air entrance in the xylem vessels via the cut surface. Role of xylem anatomy in the process related to the establishment of a good or bad rehydration are studied by means of cryo-SEM and other microscopic techniques, dynamic measurements of stem hydraulic resistance and 1H NMR imaging. Modeling techniques are use to explore theoretical concepts and to integrate experimental results obtained by the different experimental techniques.

Evidence for a wounding-induced xylem occlusion in stems of cut chrysanthemum flowers

A temperature-dependent xylem occlusion was found in cut chrysanthemum stems (Dendranthema grandiflora, cv. Viking) which were placed for 24 h in air at 5°C prior to vase life evaluation. The response was inhibited by a 5-h treatment, prior to placement in air, with aqueous solutions at low initial pH or solutions containing near-neutral antioxidants (n-propylgallate, phloroglucinol, butylated hydroxytoluene). Bacteria are known to occlude stems, but the occlusion was not related to bacterial counts in the stem ends. The number of cavitations in the xylem conduits, detected by ultrasonic acoustic emission, remained low during the storage treatment at high ambient relative humidity. The uptake of air into the stem ends ceased within 20 min whereas the occlusion developed only after several hours, showing that aspired air was not the sole cause. A xylem blockage was also found in stems placed in water directly after cutting. In these flowers, treatments with anti-oxidants delayed the occlusion, but did not affect the number of bacteria in the stem ends. The onset of xylem cavitation occurred after the occlusion. The results suggest that the stem forms a xylem blockage both during dry storage and in stems directly placed in water. The blockage apparently involves oxidative reactions.

AIR IN XYLEM VESSELS OF CUT FLOWERS

Until now all studies on the role of air emboli in the water uptake of cut flowers describe indirect methods to demonstrate the presencFe of air in the plant tissues. Using cut chrysanthemum flowers, this report is the first one that directly visualises both air and water in xylem ducts of cut flower stems, by observing transversal sections of frozen stalks in a cryo scanning electron microscope (cryo-SEM). After cryo-fixation frozen stems were sawed transversally at a desired height, polished with a cryo ultra mill, lightly etched, sputtered with platinum and investigated with the cryo-SEM. This method allows for detailed studies on the origin and fate of air emboli on water balance in cut flower stems.

Machine vision based quality evaluation of chrysanthemum cut flower

Cut flower evaluation has been usually conducted by human sense and its criteria are uncertain and subjective. In this paper, machine vision based quality evaluation was done using neural networks to quantify the ambiguous criteria. As input parameters of neural networks, cut flower length, stem diameter, leaf area, and etc. were selected, while human evaluation score was used for an output parameter. The neural networks were trained by KNT method. From the results, it was observed that output value satisfactorily agreed the human evaluation score. The error was less than the human error resulted from the human double check procedure.

Effect of time since harvest and handling conditions on rehydration ability of cut chrysanthemum flowers

Fresh cut chrysanthemum (Dendranthema x grandiflorum ‘Cassa’) flowers rehydrated fully after rapid water loss over 1 h at 20°C, 60% relative humidity (RH), and 14 μmol·m−2·s−1 light, the water loss being 5% of their fully saturated fresh weight. For rehydration after desiccation, it proved important that flowers were cut at a minimum distance above soil level. The water status of cut flowers dry-stored in darkness for 24 h at 20°C with minimal water loss (∼1%) decreased sharply during the first days of subsequent vase life. Flowers stood for 3–4 h in 20°C water and at low light intensity (14 μmol·m−2·s−1) followed by ‘desiccation’ did not rehydrate after the desiccation, but decreased further in fresh weight when returned to water. Rehydration ability of these flowers was restored, however, when the stem ends were trimmed by 7 cm under water after desiccation. Recutting in air did not restore rehydration ability. After periods of 4 or 24 h at 20°C in 5°C water at low light intensity followed by desiccation, flowers regained their water status during subsequent vase life. Flowers stood for 24 h in 20°C water and at high light intensity (187 μmol·m−2·s−1) followed by desiccation rehydrated almost fully when returned to water. It is proposed that an undefined ‘rehydration-inhibiting’ process starts after harvest, which is not due to dehydration of xylem walls or other stem tissue, or to the growth of microorganisms.

The effects of crop density on plant growth and variability in cut-flower chrysanthemum (Chrysanthemum morifolium Ramat.)

SummaryThe effects of crop density on chrysanthemum plant yield and variability were studied using two cultivars, Snowdon and Delta, in four experiments (spring, summer, autumn and winter) using fan design layouts of gradually increasing space per plant. Average total fresh weight per plant varied greatly between experiments, but empirical linear regression relationships showed that changes in space per plant gave near proportional changes in weight per plant over the whole range of densities sampled. This suggests that the density responses were essentially mediated by the available light per plant. A simple three-parameter model was developed incorporating the accumulated light integral and this gave an excellent fit to data in all four experiments. The fresh weight of flowers per plant was allometrically related to ``productive'' plant weight which was defined as total plant weight minus a fixed weight not contributing to flower production. The relationships showed that the proportional partitioning of fresh weight to the flowers differed between the cultivars and varied between the experiments, being greatest under conditions of an increasing daily light integral (spring) and least under conditions of a declining daily light integral (autumn). The log coefficient of variation of total fresh weight per plant was found to increase with increase in plant density and was greatest under winter conditions. The log coefficient of variation of `Snowdon' was generally greater than that of `Delta' at harvest, although at planting the two were similar. Polynomial regression relationships between average fresh weight and the log coefficient of variation obtained when data from all four experiments were pooled, suggested that competition for light was a primary determinant of variation. Increasing density was associated with progressively slower flowering and this trend was most pronounced in `Delta' and in the autumn and winter experiments. Stems were generally reduced in length at high density but this was not always the case. The development of a simple model to predict average stem weights and grade-outs for given spacings at particular times of year is discussed.

輪ギクの品質評価に関する研究 （第１報） 専門家の評価結果とキクの形態的特徴との関係

あいまいな基準で行われている輪ギクの切り花の評価を定量的に表現し, その自動化を計る目的で, 種々の栽培条件で得られた様々な形態的特徴をもつ材料を基に2名の専門家による評価および特徴量の計測を行った.その結果, 以下のことが明らかとなった.1) 専門家の評価結果から, 異なる評価者では結果が異なること, 同一材料の2回目の評価結果では, 1回目と異なる結果を与えることより, 人間の評価はあいまいで, 不確実であることが確認された.2) 専門家の評価基準に基づく各特徴量と, 専門家の評価結果との相関は低く, 単独の特徴量で評価を行うことは困難であった.3) 評価の自動化を計るには, 適当な特徴量を組み合わせ, 総合的評価を可能とする必要があること, およびニューラルネットワークのように, 教師データを用いて学習する形式のシステムを用いることが適当と考えられた.

Role of Sucrose in Gamma-irradiated Chrysanthemum Cut Flowers.

Vase solution containing 2% sucrose prevented the deterioration of chrysanthemum (Dendranthema grandiflorum Kitamura) cut flowers induced by gamma-rays at 750 Gy. Glucose, fructose, and sucrose in florets and leaves of irradiated chrysanthemums decreased more rapidly than those of unirradiated ones, when the cut chrysanthemums were held in a vase solution without sucrose. The sugar contents of florets and leaves and the respiratory rate of irradiated chrysanthemums held with sucrose remained at higher levels than those of unirradiated ones. Incorporation of (14)C from [(14)C]sucrose into CO2 was increased by irradiation. Incorporation of [α-(32)P]dTTP into trichloroacetic acid (TCA) insoluble substances in florets was increased by irradiation and by exogenous sucrose supply. These results suggest that sucrose in a vase solution was used as a respiratory substrate and facilitated the repair of radiation-induced damage, resulting in the extension of longevity of irradiated chrysanthemums.

Proline level in leaves and yield of cuttings and flowers of chrysanthemum as influenced by different root zone conditions

Chrysanthemum stock plants and cut flowers were grown in the greenhouse under different root zone conditions. Proline levels in the leaves were measured as an indicator of the relative stress and related to the yields of cuttings and flowers. The plants were grown in peat-based substrates or in the cultivation system plant plane hydroponic (PPH), using different fleeces as substrate. PPH plants contained higher proline levels with higher temporal variation and had lower yields as compared with the non-hydroponic systems. Proline levels and the corresponding yields indicated similiar proline threshold ranges for the yield reduction of both stock plants and cut flowers.

菊の花台のインピーダンスに及ぼすガンマ線の影響

Impedance of receptacle of chrysanthemum cut flower was increased by irradiation at 750Gy. However, holding chrysanthemum stems in 2% sucrose did not influence the impedance of both unirradiated and irradiated chrysanthemums.

Sugars Prevent the Detrimental Effects of Gamma Irradiation on Cut Chrysanthemums

Aqueous solution (2%) of sucrose, glucose, fructose, or maltose delayed bloom wilting and foliage yellowing of cut chrysanthemums [Dendranthema ×grandiflorum (Ramat.) Kitamura] caused by gamma irradiation at 750 Gy. Solutions of silver thiosulfate, sodium dodecylbenzenesulfonate, polyoxyethylene lauryl ether, potassium sorbate, mannitol, sorbitol, glycerol, 6-benzylamino purine, and gibberellin did not reduce irradiation damage. Holding chrysanthemum cut flowers in a sucrose solution before and during irradiation did not influence the vase life, but holding the cut flowers in a sucrose solution following irradiation prolonged the vase life. The results suggest that sugars reduce radiation-induced physiological deterioration of chrysanthemums.

Preservative solution for gamma irradiated chrysanthemum cut flowers

Yellow mini-chrysanthemums were irradiated in a Cobalt-60 Gammacell at the dose of 900 Gy (467 Gy/h) one day after harvest. Samples of 50 flowers, parcially opened buds were used to estimate the flower viability. Aluminum sulfate and 8-hydroxyquinoline sulfate were used as two preservative solutions aiming to protect the cut flowers. Our results indicated that the stem immersion in the preservative solutions before and after the irradiation treatment was an efficient procedure, stimulating the flowers development and maintaining the vase-life almost as long as the controls. The present work concludes that it would be possible to use preservative solutions to minimize the damaging effects of the ionizing radiation on chysanthemum cut flowers, maintaining at the same time the disinfestation action of radiation processing.

349 PROTEINS IN CHRYSANTHEMUM AS AN INDICATOR OF FLOWER LONGEVITY

It is generally accepted that ethylene production is centrally located in petal senescence, however, non-climacteric flowers senesce irrespective of the presence of ethylene. The regulation of flower senescence may well be linked to protein synthesis. Our objective was to develop a simple tool which can be used in breeding programmes and\or the market place to determine potential longevity of a flower. Here, SDS-PAGE protein profiles of both potted and cut chrysanthemum flowers were determined from flowering to senescence. Generally, only minor changes in both protein content and the proportion of the major polypeptides were observed in the potted flowers. However, polypeptides at 40, 45 and 65 kDa increased during flower senescence and are of particular interest because they could be linked to flower longevity. The apparent stability of the proteins may contribute to the long postharvest life of the potted chrysanthemum.

The production of crysanthemum (Crysanthemum morifolium Ramat.) in the east of Mexico State and its perspective in the f

The production of crysanthemum (<em>Crysanthemum morifolium </em>Ramat.) in the east of Mexico State and its perspective in the face of the North American free trade agreement SUMMARY. In the east region of Mexico State, the producer of chrysanthemum cut flowers, faces today an alternative the is being confronted to the implementation of the Free Trade Agreement, due to socio-political problems as well as technical-financial, first, within the scope of the social and political media atmosphere, the productive structure is made up of small surface and scarcely organized producers; technically and financially, there is scarcity of skilled personnel and a banking structure little interested in this activity, although there is an internal market well developed and with prices which are always higher to those of the external market. This implementation of the Free Trade Agreement opens the possibility of developing this region by establishing groups of producers who can insert themselves in the external market; or the productive structure is at the risk of disappearing in the event that foreign interprises settle down in the region that can cause an unequal competition, taking intro account that when NAFTA is implemented, 61 percent of the agricultural products, among them flowers, will be free of taxes.

養液栽培におけるカリウムの施用量とキクの生育

The relationship between growth of chrysanthemum cv. Seiun and their potassium (K) up-take capacity from hydroponic solutions of various K concentrations was investigated. From the results the optimum K application level for cut flower production was derived.1. In Experiment 1, the growth rates of plants grown at 30, 75, 150 and 300 ppm K were similar up to the flower budding stage. At 30, 75 and 150 ppm K, the chrysanthemum plants absorbed the same amount of K; at 300 ppm K, plants absorbed 1.2 times more K.2. In Experiment 2, which began on 3 May and ended on 28 June, there were six plots: one was adjusted weekly to 150 ppm K; the other five plots were supplied 2, 000, 1, 500, 1, 000, 500 and 100 mg K per plant at the beginning of the experiment. Plants supplied 2, 000, 1, 500 and 1, 000 mg K produced the good quality cut flowers; those supplied 500 mg K had small upper leaves, whereas middle and lower leaves of plants given 100 mg K exhibited necrosis and/or chlorosis, typical K deficiency symptoms. Plants grown at a constant 150 ppm K level had excessively large leaves and short flower stalks.3. Potassium contents in leaves and roots increased with increasing K concentration in the culture solution. Even when 2, 000 mg per plant were absorbed, excess K symptom was not observed. When leaf K content decreased below 4.0% on a dry matter basis, leaf Ca and Mg contents increased inversely.Based on our results, we recommend that 25 to 30 kg of potassium fertilizer (as K2O) is applied to produce 40, 000 cut chrysanthemum flowers per 1, 000m2 of green house space.

Role of air embolism and low water temperature in water balance of cut chrysanthemum flowers

The water balance of cut chrysanthemum flowers (Chrysanthemum morifolium cultivar ‘Cassa’) which had been dry stored and dehydrated did not recover, but deteriorated from the first day of the vase period. During the vase period, the water balance was affected to a greater extent by a preceding dry-storage period (with a minimal loss of water) than by preceding water loss. The water balance could be restored by vacuum rehydration or by placing the stems for 2 h in cold water (0–5°C). Low water temperature also improved the water balance of flowers immediately after cutting, but any influence of low water temperature was absent when flowering stems were previously fully hydrated. It is concluded that there could be two separate mechanisms for water uptake in cut chrysanthemum flowers; one of them is blocked by air (or other gasses) coming into the stems and the other one by a period of dry storage. Air blocking the water uptake seems to be removed by placing the stems in cold water.

Water relation of cut chrysanthemum flowers.

The wilting of florets in chrysanthemum was associated with a decline in the water potential of flowers and leaves. Stomates in the leaves tended to close when leaf diffusive resistance increased. Vascular occlusion in the stems occurred 3 days after harvest and the degree of vascular blockage increased with time. This was accompanied by a decline in stem conductance and an increase in xylem cavitation. The physical xylem blockage, however, remained concentrated in the basal region. The occluding material showed a positive reaction for pectinaceous substances, polysaccharides and proteins but was devoid of lignins and tannins.

Costs and Benefits of Quarantine Measures against Liriomyza trifolii in Finland1

In order to prevent the entry of Liriomyza trifolii into Finland the importation of rooted chrysanthemum, gerbera, cucumber, tomato and lettuce plants is prohibited, as well as the importation of chrysanthemum cut flowers and leaves of gerbera. Unrooted chrysanthemums and gerberas must be cultivated in quarantine for two weeks before they are approved. During 1982 the total costs of this quarantine survey were 70,000 Fmk. Eradication of the pest has been more expensive; in 1980 its eradication from eight glasshouses caused total costs of 380,000 Fmk to the government, and in 1982 the corresponding figure with four glasshouses was 280,000 Fmk. The range of costs of chemical control in glasshouses growing vegetables and chrysanthemums while « living with »L. trifolii are estimated to be 0.8–8.8 million Fmk depending on whether 10 or 100 % of the growing area is to be treated. When all the costs caused by exclusion measures are summed (eradication + quarantine) and compared with the costs of « living with » the pest, the ratio will be 1: 3 to 1: 13 depending on the use of insecticides. The secondary effects of additional use of insecticides on biological control or marketing difficulties because of residues are not included in this comparison. In this case the most economical way of avoiding problems caused by L. trifolii is to invest in pre‐entry quarantine measures and prevent its spread into the country.

The « Green Corner »; a Pre‐export Inspection System for Chrysanthemum Cutflowers and Pot Plants in The Netherlands1

Under the « green corner » export inspection system for chrysanthemum cut flowers and pot plants, an intensive pre‐export inspection is preceded by a registration and inspection system of the nursery and by an inspection and marking of the produce with a green sticker at the auction. This inspection system gives a high level of security that the produce is free from Liriomyza trifolii and Puccinia horiana. It is in operation to fulfil the stringent import requirements of some countries.

On a Growing District of Cut Chrysanthemum Flowers in Shodo Island

On a Growing District of Cut Chrysanthemum Flowers in Shodo Island