Journal of Ornamental Plants
Volume:13 Issue: 2, Spring 2023

Light Emitting Diodes (LEDs) can be used as a tool to control the quality of plants in order to meet the requirements of the market by accurately schedule uniform flowering based on a predetermined market date. The aim of this study was to investigate the effect of different light qualities of red (R), blue (B), and UV-A (UV) provided by LEDs, and white light produced by fluorescent lamps (FL) on growth, morphology and flowering characteristics of African violet (Saintpaulia ionantha Wendl.). An experiment was conducted in controlled environment growth chambers at 25 °C. Three ratios of R:B (1:0, 3:1, 0:1) and FL (14 h/d) were used as all-day treatments and UV LED (2 h/d) was supplemented for three ratios of R:B (1:0, 3:1, 0:1) and FL (14 h/d) as end of day (EOD) treatment. Statistical analysis showed addition of B to light spectrum inhibited abnormal leaf growth and promoted compactness. Flowering under FL treatment was distinctly inferior as measured by the number of floral buds, full blooms and inflorescences. However, addition of EOD UV plus R3B1 contributed to higher production of floral buds and full blooms in a short period of time. Supplementing UV light to LED treatments resulted in accelerated leaf expansion. Generally, supplemental UV plus R or B was an acceptable energy-efficient alternative for improving quality of African violet. Vegetative and reproductive phase of Saintpaulia were a function of light quality which could assist the predictability of flowering time in controlled environment systems.

Seed germination of some woody species is done with difficulty and at a low rate due to various reasons, including physiological and mechanical dormancy and the presence of inhibitory substances in the seed tissues. Priming is one of the most important treatments to increase the germination capacity of seeds. The purpose of this study was to investigate the effect of different treatments of stratification and sulfuric acid on the growth and germination percentage of Robinia pseudoacacia, Ailanthus altissima and Fraxinus excelsior seeds. This research was done as factorial in the randomized completely block design with two factors; plant and stratification in four replications. The results showed that the highest percentage of germination (72%) was obtained in the 50% sulfuric acid treatment on R. pseudoacacia, seeds and the lowest one (18 and 12%) in the control and 95% sulfuric acid treatments on F. excelsior seeds, respectively. The overall results of this research showed that the best stratification treatment for most of the measured traits was 50% sulfuric acid and 3°C cold for 20 days.

Water scarcity is a serious problem affecting young plants' growth, development, and establishment. Superabsorbent polymers (SAPs) have revealed an excellent capacity to absorb and retain water, increase soil moisture, and improve the growth of plants under water shortage. A greenhouse study was performed with three irrigation regimes (50%, 75%, and 100 % FC) and three levels of SAP-A200 (0, 1, and 2 g kg-1 soil) in a factorial experiment based on a completely randomized design with four replications. The results showed that soil water deficit affected physiological and biochemical characteristics of young myrtle plants. Photosynthetic parameters, total chlorophyll, and relative water content (RWC) decreased by increasing water-deficit stress. In contrast, leaf electrolyte leakage (EL), malondialdehyde (MDA), total soluble sugars (TSSs), and starch, increased. However, the application of minimal amounts of SAP (1 and 2 g kg-1 soil) improved most of these characteristics in both well-watered and water-deficit conditions, it appears that a higher amount of SAP is needed in moderate and severe water stress conditions. Therefore, SAP-A200 can be utilized as an efficient and economical method for rapidly establishing woody young plants in low-water areas.

Drought stress is one of the most prevalent problems that limit the growth and lifespan of plants. Knowing the specifics of plant response to drought stress can be useful in the management and development of plant cultivation. The feverfew plant (Tanacetum parthenium L.) is ornamental and medicinal plant native to Iran and its cultivation in the landscape seems valuable as a wildflower due to its beauty. The factorial experiment was conducted to investigate the effect of biochar and vermicompost on feverfew (Tanacetum parthenium L.) in loamy soils under drought stress conditions based on a completely randomized design (CRD) in three replicates. The results showed that drought stress caused a decrease in shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, and leaf relative water content (RWC), compared to the control treatment. On the other hand, there was an increase in catalase enzyme because of the drought stress. By improving the soil condition, vermicompost and biochar caused an increase in fresh and dry weight of shoots and roots, chlorophyll content, and leaf RWC. However, it decreased the activity of catalase and superoxide dismutase enzyames. In general, the combination of vermicompost and biochar was the best treatment for enhancing the soil condition and increasing the growth characteristics of feverfew plants under drought stress.

Chrysanthemums are known as one of the top three flowers in the floriculture industry. This ornamental plant is traditionally propagated by cuttings. The use of in vitro subculture is expanding for plants like chrysanthemums that are propagated by asexual methods. This research evaluated the effect of plant growth regulators on callus induction and regeneration in three chrysanthemum cultivars including ‘Bonfire Yellow’, ‘Rambla’, and ‘Bella Rosa’. For callus generation, the leaf explants were cultivated in the Murashige and Skoog (MS) culture medium modified with with benzyl adenine (1, 2, or 3 mg/L BA) and naphthaleneacetic acid (0.5 or 1 mg/L NAA) in a factorial experiment based on a completely randomized design. The highest rate of regeneration of ‘Bonfire Yellow’(31.25%), ‘Rambla’(25%), and ‘Bella Rosa’ (31.25%) were obtained from the culture media containing 2 mg/L BA + 1 mg/L NAA, 1 mg/L BA + 1 mg/L NAA, and 3 mg/L BA + 0.5 mg/L NAA, respectively.

Petroleum sludge is the waste of crude oil refining processes, and are the most priority organic pollutants found in the environment. The present study was carried out to evaluate the growth and phytoremediation ability of ornamental tall fescue (Festuca arundinacea Schreb.) and sunflower (Helianthus annuus L.) plant to petroleum sludge produced by Isfahan Refinery in contaminated soils in a greenhouse experiment. For this purpose, the air-dried petroleum sludge sample was added to an uncontaminated soil at ratios of 0 (control), 10 and 20% (w/w) and mixed thoroughly. Plastic pots were filled with called mixture (3 kg). The experiment layout consisted of split-plots arranged in a completely randomized design with three replicates. The results showed that with increasing sludge level from 0 to 10 and 20 %, the tall fescue germination decreased significantly (P<0.01). In sunflower plant this decrease was not significant. The mean values of plant heights and root and shoot dry weights for tall fescue only in 20% level of petroleum sludge showed a significant reduction when compared with control. However, in sunflower plant, this reduction was not significant in all three petroleum sludge levels (P<0.01). The highest reduction of total petroleum hydrocarbons (89%) in tall fescue rhizosphere was observed in petroleum sludge level of 10%. By increasing the petroleum sludge up than 10%, total petroleum hydrocarbons in rhizosphere of two plants significantly decreased (P<0.01). Because, tall fescue plant produces more roots than shoots and have more fibrous root systems that caused more reduct TPH, application this plant recommend as a appropriate species for phytoremediation of contaminated soils to petroleum sludge of Isfahan Refinery.