The Effect of Polyamines and Silver Thiosulphate on Micropropagation of Date Palm Followed by Genetic Stability Assessment

There are some limitations in the practical applications of in vitro date palm tissue culture, such as low multiplication efficiency, low rooting rate, and high mortality experienced by in vitro raised plantlets during laboratory to soil transfer. This study’s objective was to investigate the effect of the two types of polyamines (putrescine "PUT" and spermidine" SPD") in combination with silver thiosulfate (STS) on the growth and development and genetic stability of cultures of Quntar cultivar. Media supplemented with 75 mg L−1 SPD in combination with 10 mgL−1 STS gave the highest percentage of callus producing buds (83.34%) and average bud formation (16.3) per jar. The addition of PUT and STS to the medium was most effective in root formation and the number of roots per shoot, where the best result 91.67% and 6.37 roots per shoot, respectively, were obtained using 75 mgL−1 PUT and 10 mgL−1 STS, resulting in fast-growing plantlets during acclimatization phase, reaching 90% of plant survival. The genetic fidelity assessment of plants derived from micropropagation was confirmed by RAPD analysis. Four operon primers were used, and all of them showed amplified unambiguous (OPA02, OPC-04, OPD-07, and OPE-15). All generated bands were monomorphic and had no variation among the tissue culture-derived plants tested. Accordingly, these results indicate that adding polyamines and silver thiosulfate to the nutrient medium of date palm cv. Quntar is beneficial in improving shoot organogenesis, rooting, and production of genetically stable date palm plants.

THE EFFECT OF CHEMICAL TREATMENTS ON THE QUALITY AND LIFE OF VASES IN THE CUT FLOWERS OF CARNATIONS (DIANTHUS CARYOPYLLUS L.)

The cut flowers are living organs, with intense metabolic activity, subjected to a rapid aging process compared to the undetached flowers from the mother plant. Improving the life of cut flowers is one of the most important factors for customer satisfaction. The effect of silver thiosulphate (STS) and commercial mixtures was studied in carnation cut flowers and kept in randomized vases according to experimental factors. Three commercial mixtures were used (Chrysal, Flower Food, Fleur̛ Rose) and for thiosulphate four levels (0 or control, 0.03, 0.06 and 0.9 mM). The interaction of the two factors studied was insignificant for most traits, including wilting percentage and vase lifespan, which may involve the application of both substances alone is sufficient to improve post-harvest quality and is not necessary to use simultaneously in the preservative solution. The results also showed that following the interaction of the two factors, treatment with 0.06 mM silver thiosulphate can be applied to improve the post-harvest quality of blossom cut flowers and commercial chemical mixtures can be successfully replaced.

Aloe vera and STS solution on microbial population and vase life of Heliconia cut flowers

The use of several solutions as floral preservatives in extending the vase life of cut flowers has been an all-time research objective to meet the demands of florists and buyers. One of the major problems faced with the longevity of cut flowers is the accumulation of microorganism in the vase floral solution. This study was carried out to investigate the influence of Aloe vera gel and Silver thiosulphate solutions used as vase solution on the microbial population of Heliconia cut flowers. The experiment was carried out in the plant physiology laboratory, Floriculture programme, National Horticultural Research Institute, (NIHORT); Ibadan, Nigeria (7O25” N and 3O52” E). Six treatments supplemented with 1% sucrose were used in this experiment, they include; 1%, 2% and 4% Aloe vera gel solutions, 0.5% and 1% Silver thiosulphate solutions and distilled water (which serve as control) labeled AV1, AV2, AV3, STS1, STS2 and CO respectively. All treatments used for the vase life of Heliconia cut flowers were significantly (p ≤ 0.05) different in the parameters analyzed as compared to the control. The vase life, relative fresh weight and relative water content of Heliconia cut flowers were best with Aloe vera gel solutions compared to the control with AV3 recording the longest vase life of 12 days (58.21%). The microbial population in the vases of the cut flowers was greatly reduced with the application of the silver thiosulphate solutions (STS1 and STS2) compared with the control with STS2 recording the lowest microbial colony at 32.67 CFU mL-1. Promoting the use of organic floral preservatives should be encouraged as it is eco-friendly and cost effective. The result of the study reveals that the use of 4% Aloe vera solution has the potential to reduce microbial growth and also enhance the longevity of the cut flowers.

Effects of pretreatment on the cut flowers quarantined by EB radiation

Fresh cut flowers including yellow and white chrysanthemum (chrysanthemum sp) and red carnation (Dianthus caryophyllus L) were electron beam irradiated as quarantine treatment. The results showed that the irradiated flowers could meet the phytosanitary requirements in the international trading. In this study, the cut flowers were pretreated with the commercial preservative and sugar solutions in order to increase their radio-tolerance and expand their vase-life. The pretreatment has also reduced the weight loss, browning rate of leaves, and brightness of the irradiated flowers. The results revealed that the commercial quality of the irradiated cut flowers pretreated with 2% glucose solution 2 hours, then 0.024% silver thiosulphate (STS) solution for further 2 hours was remained after storage at 4-6oC. Pre-treatment with 2% glucose and 0.024% STS before irradiation at 400 Gy and 600 Gy was chosen as the best way for improving the raditain tolerance of the cut flowers. The vase-lifes of the irradiated cut flowers are 6 days for yellow chrysanthemum; 8 days for white chrysanthemum and 8-10 days for red carnation similar to non-irradition ones.

Extension of the vase life of Lilium pumilum cut flowers by pulsing solution containing sucrose, citric acid and silver thiosulfate

Floriculture is a promising activity and has great economic importance. In this context, the cultivation of Lilium pumilum Redouté stands out. However, one of the main challenges flower farmers face is that a large part of the products is lost before reaching the final consumer, due to postharvest losses. Such losses can be minimized by adopting some techniques, such as the use of conditioning solution (pulsing), which has been effective in preventing early senescence. In this sense, this study aimed to evaluate the effect of pulsing with sucrose, citric acid and silver thiosulphate on postharvest conservation of L. pumilum cut flowers. All treatments promoted a 1.8±0.3 day increase in longevity, uniformity of floral opening, and reduced fresh weight loss compared to the control (flowers that were not pulse-treated). There was no significant difference in chlorophyll content and leaf relative water content. The time of exposure to pulsing caused significant differences in the reduction of anthocyanin contents when compared to the control, demonstrating that pulsing preservative solution for at least 6 h extends the vase life of L. pumilum cut flowers by two days.

Effect of Ethylene Antagonist Silver Thiosulphate on the Flower Longevity of Clarkia pulchella Pursh.

An experiment was conducted to study the effect of different concentrations of silver thiosulphate (STS) on flower longevity of Clarkia pulchella Pursh. The buds were subjected to 0.1, 0.25, 0.5, 0.75 and 1 mM of STS for 1 h pulse treatment. A separate set of flowers kept in distilled water was designated the control group. STS treatment resulted in improved flower longevity besides maintaining higher fresh and dry mass, water content and floral diameter. Conversely, total phenols, lipid peroxidation and lipoxygenase (LOX) activity decreased. The flowers treated with STS showed a significant increase in the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX). Amongst various grades used, 0.5 mM STS was found to be most effective in enhancing the flower longevity by 1.5 days. The present study reveals that STS maintains lower LOX activity, thereby increased membrane stability index by improving the activity of antioxidant enzymes.