Evaluation of Postproduction Performance of Salvia splendens Potted Plants for Interiors Use

In recent years, herbaceous flowering potted plants have widely been used to be planted in garden area but these species might be also used as interior plants. Post production performance of flowering potted plants under interior conditions has become a research area of great interest. The aim of this work was to evaluate whether Salvia splendens may have a potential use as short-term colour source in interior environments. S. splendens cv.Flamex 2000 were grown in greenhouse until to reach the commercial stage, then they were transferred to a room with interior environment conditions (14 hours photoperiod, 15-25°C night/day, light intensity 10 μmol m s). Moreover, plants were treated with water (Control) or solutions containing 1 mM 1-aminocyclopropane-1-carboxylic acid (ACC), 1 mM aminooxyacetic acid (AOA) or 500 μM Benzyladenine (BA). During the experiment period ornamental quality parameters such as flower longevity, inflorescence length, number of abscised flowers and ethylene production were determined. Salvia plants under interior conditions showed reduced their longevity to half compared to those plants kept in the greenhouse. Results showed that ornamental quality was acceptable for more than two weeks. This period is long enough for classifying salvia as interior plants. The main symptoms of flower senescence were the incomplete flower opening on the spikes and the following abscission of flowers, which cause a reduction of the ornamental value of the plants. Anyway, our results suggest that salvia potted plants might be used in interior environments and open new market opportunities for this ornamental species. INTRODUCTION Flowering bedding plants are usually used as decoration of public and private gardens. The success of this annual floriculture items are probably due to the low production cost, the repeat-flowering ability, the wide range of colours and species available. The beauty of these flowering plants can be also appreciate for a short period of time in indoor environments with limited light intensity, inadequate temperature and air humidity (Satterthwaite and Conover, 1996). The use of bedding plants for indoor use has been gaining importance for decorations of rooms, halls, conference rooms, offices, waiting rooms and finally the consumer’s house (Mensuali-Sodi et al, 2003). The postproduction quality of flowering plants for interior use should be long enough for covering special events such as meetings, conference or simply for short period but at least a week in restaurants and offices. The ornamental quality of flowering bedding plants is mainly represented by the flower longevity, but also by the number and size of flowers. However, the flower life is the limiting factor for indoor use of bedding plants. The lack of adequate photosynthetic light intensity and relatively high temperatures induce reserve losses, leading plants to quality losses (Conover et al., 1993). The evaluation of post-production flower longevity has to be evaluated in rooms that simulate the indoor environments, even if with air pollutants such as ethylene (Cameron and Reid, 1983). The aim of this work was to evaluate the potential use of Salvia splendens as interior plant. The applications of inhibitors and promoters of ethylene were used to inhibit or stimulate flower senescence in Salvia plants placed in limiting environments. 415 Proc. I IC on Labiatae Eds.: B. Ruffoni et al. Acta Hort. 723, ISHS 2006 MATERIALS AND METHODS Plant Material Plants of Salvia splendens Kerr Gawl cv.Flamex 2000 were grown in greenhouse under natural conditions (April-July). Seeds were bought from S&G Sementi Spa (Como, Italy). Seeds germination was performed in a growth chamber at 26°C. Seedlings at 2-4 true leaves stage were transplanted in trays. Fertigations were performed every 10 days with soluble fertilizer (10:12:27) containing 1 g l Fe, Cu, Mo, B (Poly Feeds, Haifa Chemicals LTD). Watering was performed every day. Treatments and Indoor Environment Conditions At commercial stage, the flowering plants were placed in a chamber simulating the indoor conditions: 14 h photoperiod, 10 μmol m s light intensity PPFD, temperature ranging from 15 to 25°C (night/day, May-July). Flowering plants were spray treated until run-off with solutions containing 500 μM Benzyladenine (BA, Milano, Sigma), 1 mM amino-oxyacetic acid (AOA, Milano, Sigma) and 1 mM 1-aminocyclopropane-1carboxylic acid (ACC, Milano, Sigma) Sampling and Measurements During the post-production the visual appearance, the plant height, the flower production, flower senescence, plant senescence and ethylene production were measured at the beginning of trial and after 6, 12 and 19 days. Ethylene production was measured by enclosing flowers in airtight containers. Two ml gas samples were taken from the headspace of the containers with a hypodermic syringe, after 1 h incubation at room temperature. The ethylene concentration was measured using a gas chromatograph (HP5890, Hewlett-Packard, Menlo Park, CA) with a flame ionization detector (FID), and a stainless steel column (150 x 0,4 cm ø packed with Hysep T). Column and detector temperatures were 70° and 350°C, respectively. Nitrogen carrier gas was used at a flow rate of 30 ml min. Statistical Analysis The data reported are means with respective standard errors or percentages. Each treatment was composed by 12 plants. Data were subjected to ANOVA analysis and differences among means were determined by Bonferroni’s post-test. RESULTS Flowering S. splendens plants were used for evaluating their performance as interior or indoor flowering plants. The visual appearance or the ornamental quality of Salvia plants placed indoor was evaluated until 19 days. Treatments with AOA and BA prolonged the flower longevity of salvia. In particular, BA increased the percentage of open flowers, on each inflorescence after 12 and 19 days in indoor conditions (Fig. 1). Therefore, it stimulated the flower opening on Salvia plants. After 12 days the percentage of open flowers was about the 90% and the 100% after 19 days (Fig. 1). By contrast, salvia plants treated with ACC showed the lowest percentage after 12 days and did not change after 19 days (Fig. 1). The AOA, instead, did not improve the flower opening after 12 days compared with control, but differences were observed after 19 days of permanence in indoor environment (Fig. 1). Considering the number of flowered plants, differences were found after 6 days of indoor simulation. Control and BA treated plants flowered before than AOA and ACC treated Salvia. Anyway, all plants had open flowers after 12 days of indoor permanence. Treatments with ACC strongly induced flower abscission. After 6 days ACC treated plants showed the 75% of flowers abscised (Fig. 2). By contrast, AOA inhibited flower senescence and delayed the abscission of flowers. In fact, abscised flowers, in treatments with AOA, were found at the end of evaluation period with about 50% of flowers lost (Fig. 2).