EFFECT of GROWTH REGULATORS on the POSTHARVEST LONGEVITY of CUT FLOWERS and LEAVES of the CALLA LILY (Zantedeschia Spreng.)
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ACTA AGROBOTANICA Vol. 64 (4): 91–98 2011 EFFECT OF GROWTH REGULATORS ON THE POSTHARVEST LONGEVITY OF CUT FLOWERS AND LEAVES OF THE CALLA LILY (Zantedeschia Spreng.) Beata Janowska, Anna Stanecka Department of Ornamental Plants, University of Life Sciences in Poznań, Dąbrowskiego 159, 60-594 Poznań, Poland e-mail: [email protected] Received: 10.07.2011 Abstract medium brings about a rapid drop in the hydration le- The conditioning of flowers of the calla lily cultivar vel of tissues and the appearance of necrotic spots on ‘Albomaculata’ in BA at concentrations of 50-150 mg×dm-3 spathes. In a research by Janowska and Jerzy extends their postharvest longevity by 6.2-14.5 days. An exten- (2004), the splitting of peduncles was not observed sion of the longevity of the flowers by 15 days can be obtained in cultivars ‘Florex Gold’ and ‘Black Magic’, while after the application of a solution of 8HQS with saccharose on the greening of spathes appeared only in the cultivar a continuous basis. Effective in improving the longevity of ‘Florex Gold’. The authors also obtained very good leaves of cultivar ‘Sunglow’ is GA3 at a concentration of postharvest longevity in flowers, which kept their 400 mg×dm-3. What is more, its application at concentrations ornamental qualities for about 3-4 weeks after being -3 of 300-400 mg×dm boosts their greenness index. GA3 at con- placed in water. However, an undesirable develop- -3 centrations of 50 and 100 mg×dm extends the postharvest lon- ment was the rotting of peduncle ends in the cultivar gevity of leaves of the cultivar ‘Black Eyed Beauty’ by 18 and ‘Black Magic’ as a result of conditioning in a solution 11 days, respectively, while BA shortens it. A combined appli- cation of BA and GA inhibits chlorophyll degradation, while of 8-hydroxyquinoline citrate. Moreover, this practi- 3 ce shortened the postharvest vase-life of flowers by GA3 and a mixture of BA and GA3 inhibit protein degradation. 7-8 days. Ornamental qualities were preserved the lon- , gest by those flowers which had been placed after cut- Key words: Zantedeschia, flowers, florist greens, vase-life, BA, GA , 8HQS ting in solutions of gibberellic acid at concentrations 3 of 50 and 100 mg×dm-3. In the cultivar ‘Florex Gold’, postharvest longevity was the best in flowers which INTRODUCTION had been conditioned in a solution of 8-hydroxyquino- line citrate for 2 hours. In this cultivar, gibberellic acid In the recent years, research has increasingly fo- also proved effective in extending longevity, because cused on the postharvest longevity of both flowers and irrespective of the duration of conditioning in the so- florist greens, which have become an indispensable lution of 8-hydroxyquinoline citrate, the flowers that element of modern flower arrangements. So far, only had been then placed in solutions of this acid preserved a few studies have been made on cut flowers and le- their ornamental qualities several days longer. aves of the calla lily. Tjia and Funnell (1986) There has been little research so far on the post- report that the vase life of Zantedeschia aethiopica flo- harvest longevity of leaves of the calla lily. Janowska wers lasts 6-7 days after cutting, while in Zantedeschia and Jerzy (2003a) obtained the most extended vase- elliottiana the spathes turn green after 7-8 days, which -life in leaves of the cultivars ‘Florex Gold’ and ‘Black is a visible symptom of the advancing process of sene- Magic’ by conditioning them in solutions of gibberellic scence. Besides, peduncles placed in pure water tend acid at concentrations of 200 and 300 mg×dm-3. More- to split and, to prevent it, the authors recommend an over, improved longevity also involved slower chloro- addition of sugar and 8-hydroxyquinoline citrate. Ho- phyll degradation (Janowska and Jerzy, 2003b). wever, as Ł ukaszewska and Kokosa (1997) Similarly, in Zantedeschia aethiopica gibberellic acid report, in Zantedeschia aethiopica sugar added to the proved effective in extending the postharvest longevity 92 Beata Janowska, Anna Stanecka of leaves: it caused leaf longevity to increase as much 12 hours in a cold room at 5oC. The conditioning invo- as sixfold (Ł ukaszewska, 2000; Skutnik et lved water solutions of benzyladenine and gibberellic al. 2004). acid at the same concentrations of 50 and 100 mg×dm-3 The aim of the present research was to assess as well as those in which the growth regulators had the effect of conditioning of flowers in a water solution a concentration of 50 or 100 mg×dm-3. After condi- of benzyladenine and a standard flower preservative, tioning, the leaves were placed in distilled water. The containing 8-hydroxyquinoline sulphate (8HQS) and control was leaves put in distilled water. 2% saccharose, on the postharvest longevity of calla The postharvest longevity of the leaves was lily flowers of the cultivar ‘Albomaculata’ and to as- determined in days. The loss of their ornamental qu- sess the effect of benzyladenine and gibberellic acid alities was set at that point in time when they had tur- on the postharvest longevity of leaves of the cultivars ned yellow or when 30% of the leaf blades had wilted. ‘Sunglow’ and ‘Black Eyed Beauty’. Their greenness index, measured in SPAD units using a SPAD-502 Chlorophyll Meter (Gregorczyk and MATERIAL AND METHODS Raczyń ska, 1997; Gregorczyk et al. 1998), as well as their content of chlorophylls a+b and pro- The research was conducted in the Department teins were determined. Noted was the initial index of of Ornamental Plants of the University of Life Scien- leaf greenness measured at the start of the experiment ces in Poznań from July to August 2007. The culti- as well as the initial content of chlorophylls a+b and vars employed were ‘Albomaculata’ and ‘Black Eyed proteins in the leaves. Beauty’ deriving from the spotted calla (Zantedeschia The chlorophyll level was determined using the albomaculata /Hook./ Baill.) as well as ‘Sunglow’ de- method presented in Hiscox and Israelstam riving from Zantedeschia sp. (1979). It allows extracting pigments from plant ma- Flowers were conditioned for 4 hours in wa- terial with the help of dimethyl sulphoxide (DMSO) ter solutions of benzyladenine at concentrations of without tissue maceration. Weighted portions were 50, 100, and 150 mg×dm-3. They were then placed treated with 15 ml DMSO and incubated in a water in distilled water or in an water solution of 8-hydro- bath at 65oC for 60 minutes. In the extract thus ob- xyquinoline sulphate (8HQS) at a concentration of tained, the level of chlorophylls a+b was determined 200 mg×dm-3 with an addition of 2% saccharose. The spectrophotometrically. The total of chlorophylls a+b control was flowers put in distilled water. The acidi- was calculated following ARNON (1949). The amo- ty of the solutions was pH ±5. During the experiment, unts of the individual pigments were given in mg×g-1 water was changed every day and the aqueous 8HQS fresh weight. solutions were supplemented with saccharose to fill up. The determination of protein content in the le- The experiment consisted of 8 treatments, each aves was made with the help of Bradford’s (1976) involving 5 plants in 3 replications. One treatment method. 2 ml of a solution of Coomassie Brilliant Blue (BA concentration x the longevity-improving solution) G-250 (CBB) in 85% orthophosphoric acid was added consisted of 15 flowers. to 100 μl of a diluted extract, with the extraction in The postharvest longevity of the flowers was a phosphorate-potassium buffer (pH 7.0). After 10 mi- determined in days. The loss of their ornamental qu- nutes the absorbance was measured at a wavelength of alities was set at that point in time when they had tur- 595 nm. Protein content was determined from a curve ned green or when the tops of the spathes had dried. In plotted for albumin. the calla lily, a “flower” is a conventional simplifying The experiments were conducted at a tempe- term used to describe the inflorescence on a peduncle – rature of 18-20oC and a 12-h photoperiod, employing a spadix – surrounded by a spathe. white luminescence light with a quantum irradiance in- Leaves of the cultivar ‘Sunglow’ were condi- tensity of 25 μmol m2s-1. The relative air humidity was tioned for 4 hours in water solutions of GA3 at con- maintained at 70%. centrations of 300 and 400 mg×dm-3. They were then The results were processed with the help of uni- placed in distilled water or in aqueous solutions of BA variate analysis of variance. The means were grouped -3 at concentrations of 50 and 100 mg×dm . The control using Duncan’s test at the = 0.05 significance level. was leaves put in distilled water. The experiment consisted of 9 treatments, each involving 5 leaves in 3 replications. One treatment RESULTS (GA3 concentration x BA concentration) consisted of The postharvest longevity of flowers of the cul- 15 leaves. tivar ‘Albomaculata’ depended on both the concentra- Leaves of the cultivar ‘Black Eyed Beauty’ tion of benzyladenine applied for conditioning and the with petioles shortened to 40 cm were conditioned for solution used after it (Table 1). Whether the flowers Effect of growth regulators on the postharvest longevity of cut flowers and leaves of the calla lily (Zantedeschia Spreng.) 93 were placed in water after the conditioning or in a so- tiveness of both practices and shortened the longevity lution of 8-hydroxyquinoline sulphate with saccharo- of the flowers to 20.3 days. An extension of the vase- se, the longest-lived were those which had been con- -life of flowers by about 10-11 days was obtained by ditioned in benzyladenine at concentrations of 50 or conditioning them in benzyladenine at 150 mg×dm-3, 150 mg×dm-3.