Journal of Ornamental Plants
Volume:10 Issue: 2, Spring 2020

To reduce the postharvest loss of cut lisianthus ‘Pink Picotte’ flowers, an experiment was conducted based on a randomized complete design with three replications. The experimental treatments were composed of salicylic acid (SA) at three rates of 50, 100 and 200 mg L-1 and cerium nitrate (Ce(NO3)3) at four rates of 20, 40, 80 and 200 μM and distilled water (control) applied at 24-h pulses with 3% sucrose. It was found that SA and Ce (NO3)3 influenced all recorded traits significantly except for dry matter. The treatments of 40 μM Ce (NO3)3 and 100 mg L-1 SA performed the best in extending vase life so that they were associated with the longest vase lives of 15.42 and 15.20 days, respectively. In addition to improving vase life, these two treatments outperformed the other treatments in inhibiting the loss of fresh weight, reducing bacterial colony in vase solution, and increasing leaf chlorophyll. The highest catalase activity (8.57 IU g-1 FW min-1) was observed in the plants treated with 40 μM Ce (NO3)3, not differing from the treatments of 50 and 100 mg L-1 SA significantly. Furthermore, these treatments were effective in increasing superoxide dismutase activity. The results revealed that the application of 200 mg L-1 SA had adverse impacts on the vase life and the related traits. Overall, it is not recommended to apply high concentrations of Ce (NO3)3 (80 and 200 μM) and SA (200 mg L-1) in the vase solution of cut lisianthus ‘Pink Picotte’ flowers.

This study was aimed to obtain polyploid plants of viola (Viola acuminata Ledebour) using the antimitotic agent colchicine. Experiments consisted in using colchicine on ungerminated seeds. The seeds were plunged into colchicine solutions in concentrations of 0.01, 0.05, 0.10 and 0.20% for 24 and 48 h. Polyploidy levels (diploid, tetraploid and hexaploid) were firstly detected by chromosome counting (karyotype), and then confirmed by anatomical and morphological parameters. The greatest percentage of polyploids was induced with 0.10% colchicine for 24 h. The chromosome number was 2n = 18 in diploids, 2n = 36 in tetraploid, and 2n = 54 in hexaploid. Differences in some morphological and anatomical parameters were significant between polyploid and control plantlets. The highest number of chloroplasts in guard cells was obtained in plantlets obtained from treated seed with 0.10% colchicine for 24 h. Exposure times of 48 h did not significantly influence polyploidisation. New ornamental varieties with improved characteristics may be produced by polyploid induction.

Alstroemeria is one of the most popular cut flowers in European Union owing to its postharvest longevity and broad color spectra. Nevertheless, premature wilting decreases the esthetic value of flowering branches even before the opening of the secondary florets in the fluorescence. The present study evaluated different biochemical and morphological traits of Alstroemeria cut flowers in order to screen the longevity of eight cultivars of Alstroemeria cut flowers including (Topaz, Chicago, Mayfair, Onyx, Frosty, Bellevue, Samantha, and Dimension). Traits such as longevity, wilting, water uptake, chlorophyll content, total soluble solids, relative water content, catalase activity, peroxidase activity, and protein content were evaluated. Data were subjected to the statistical and cluster analysis. The results showed that Mayfair and Frosty cultivars have the greatest distance from another. Mayfair had the lowest longevity. Frosty exhibited the most significant difference and was the most different cultivar from other cultivars in terms of biochemical traits, so that it was clustered in a separate group. As a result, two cultivars with the longest and the shortest longevity was determined. Maximum peroxidase activity was related to Frosty, differing significantly from that of Mayfair.

Mulches have significant environmental, aesthetic and functional benefits. However, there are arguments that some organic types of mulches prevent seed germination and the growth of plants due to their allelopathic effects. This study examined the allelopathic influence of the extracts of some organic mulches on seed germination percentage, and growth of the seedlings of some ornamental plants in two interrelated experiments. In the first experiment, allelopathic effects of six organic mulches including pine wood chips of the plane tree, pine cones, pine leaves, pine barks, sawdust,and grass clippings of Festuca arundincea were examined on germination and early growth of lettuce seeds as an indicator species. The second experiment was designed based on the results of the first experiment so that the extracts of the mulches with the lowest germination rates were selected and their effect on seed germination of five flowering plants of Alyssum maritimum, Celosia argentea, Tagetes sp., Zinnia sp. and Rudbeckia sp. were evaluated. The results showed that pine leave extracts had inhibitory effects on germination of lettuce seeds (in the first experiment) and also showed significant and strong inhibitory effects (P<0.01) on seed germination, radicle length, plumule length, plumule fresh and dry weights of all seasonal flowers. Based on these results, pine leaves after being released in the soil or after decomposition may act as a source of allelochemicals and should be used by care as mulch in landscaping at least if it is combined with ornamental plants.

One of the most important factors in controlling the quality of fresh flowers is stem length because it is a major determinant of cut stem productivity. The grading and marketing of most cut flowers, like roses, are generally based on stem length. The present study aimed to evaluate the effects of cut rose flower stem length on vase life and water balance of rose cv. ‘Bingo White’ in a factorial experiment based on a Completely Randomized Design (CRD). Cut stem length was used at four levels of 25, 35, 45, and 55 cm kept in 50 mg/L sucrose sodium hypochlorite solution at two levels of 0 and 2% as preservative solutions with three replications at 23 ± 2°C with 65 ± 5% relative humidity and 12μmol/m2 s of light intensity (supplied by cool white fluorescent lamps) for 12 hours up to the end of vase life. Some qualitative and quantitative characteristics including vase life, flower and leaf water potential, ion leakage, membrane stability index (MSI), and leaf stomatal conductance were recorded. The results showed that the longest vase life (17 days) was significantly (P < 0.01) observed at the lowest stem length (25 cm) and the shortest vase life (10 days) was related to the highest stem length (55 cm). The lowest rate of leaf and petal ion leakage was significantly (P < 0.05) observed in the lowest stem length (25 cm). The stem lengths of 35 and 45 cm, however, did not significantly differ from the stem length of 25 cm. The lowest rate of leaf and petal membrane stability index was significantly (P < 0.05) related to 55 cm stem length. The highest rate of flower and leaf water potential was significantly (P < 0.01) obtained from 35 cm stem length as compared with other treatments. Stomatal conductance decreased over time, but it was not affected by stem length treatments significantly. Generally, our results showed that the shorter cut stem length treatment (25 cm) with the sucrose solution (2%) not only had the greatest effect on extending vase life but it also improved the water status, decreased the ion leakage, and increased the flower membrane stability index.

In this study, we investigated the effects of organic waste and moisture superabsorbent on the amount of available water and delay in moisture equivalent of permanent wilting point (PWP) in soil. In the first phase (soil incubation phase), 12 treatments were studied in a completely randomized design at the Soil Science Laboratory of Science and Research Branch, Tehran. The treatments consisted of 5 and 10% compost (mixture of municipale waste compost and cow manure); 5, 15 and 30 g/kg soil of zeolite and 2, 4 and 8 g/kg soil of moisture superabsorbents (A200). In the second phase (greenhouse phase), three treatments with the highest delay in permanent wilting point with a control treatment were selected as planting media and in a factorial experiment based on randomized complete block design, we studied the effect of planting substrate (four substrates) and irrigation period at three levels (48, 72 and 120 hours) on Aloysia citrodora growth. The results showed that the highest amount of FC moisture equivalent was related to the treatment with 8 g superabsorbent per kg soil. The highest delay in the permanent wilting point was for 8 g superabsorbent per kg of soil with a delay of 682 h. The highest total fresh weight of plant was observed in the treatment of 10 g of zeolite per kg of soil and 48 hours irrigation round with a mean of 9.47 g. In the superabsorbent treatment, leaf dry weight was higher than the control in 3 irrigation rounds. In general, the results showed that the addition of superabsorbent to the soil by delaying the plant's wilting point could save water use by increasing irrigation rounds.