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.

Vase life consequences of natural and chemical treatments in foxtail lily (Eremurus spectabilis), as a specialty cut flowers

Eremurus spectabilis is a new, commercially valuable specialty cut flower, but little is known about the applicable treatments to extend the vase-life and maintaining the ornamental quality of this flower. Therefore, the present study was aimed at investigating the impacts of nano-silver, essential oils, and chemical treatments on keeping ornamental quality and vase-life of cut inflorescences of Foxtail lily. The cut inflorescences were placed in different vase solutions containing salicylic acid (100 and 200 mg L-1), methyl jasmonate (25 and 50 mg L-1), silver thiosulfate (0.1 mM) plus isothiazolinone (0.001 and 0.005 mL L-1), nano-silver (5, 10, and 15 mg L-1), thymol (75 and 120 mg L-1), and menthol (75 and 120 mg L-1), which were applied as continuous and pulsing methods. According to the results, all treatments considerably improved the post-harvest performance of Foxtail lily cut flowers. Although there were no significant differences among nano-silver (NS) treatments, the cut inflorescences kept in vase solution containing 10 mg L-1 of NS exhibited the longest vase life (~14 days) and the best ornamental quality. Nano-silver treatment followed by silver-thiosulfate significantly improved solution uptake by flowering inflorescences, thereby delaying the water balance loss and keeping relative fresh weight. Furthermore, 50 mg L-1 methyl jasmonate- and 75 mg L-1 menthol-treated cut inflorescences exhibited significantly higher vase-life longevity by ~ 6 and 4 days, total soluble solutes by 28.38% and 19.12%, and solution uptake rate by 76.46% and 140.6%, respectively, as compared to control. Overall, 10 mg L-1 NS can be recommended as a commercial preservative solution to delay flower senescence and improve the vase life and keeping the quality of foxtail cut inflorescence.

Potential of Impedance Flow Cytometry to Assess the Viability and Quantity of Cannabis sativa L. Pollen

Over the last decade, efforts to breed new Cannabis sativa L. cultivars with high Cannabidiol (CBD) and other non-psychoactive cannabinoids with low tetrahydrocannabinol (THC) levels have increased. In this context, the identification of the viability and quantity of pollen, which represents the fitness of male gametophytes, to accomplish successful pollination is of high importance. The present study aims to evaluate the potential of impedance flow cytometry (IFC) for the assessment of pollen viability (PV) and total number of pollen cells (TPC) in two phytocannabinoid-rich cannabis genotypes, KANADA (KAN) and A4 treated with two different chemical solutions, silver thiosulfate solution (STS) and gibberellic acid (GA3). Pollen was collected over a period of 8 to 24 days after flowering (DAF) in a greenhouse experiment. Impedance flow cytometry (IFC) technology was used with Cannabis sativa to assess the viability and quantity of pollen. The results showed that the number of flowers per plant was highest at 24 DAF for both genotypes, A4 (317.78) and KAN (189.74). TPC induced by STS was significantly higher compared to GA3 over the collection period of 8 to 24 DAF with the highest mean TPC of 1.54 × 105 at 14 DAF. STS showed significantly higher viability of pollen compared to GA3 in genotype KAN, with the highest PV of 78.18% 11 DAF. Genotype A4 also showed significantly higher PV with STS at 8 (45.66%), 14 (77.88%), 18 (79.37%), and 24 (51.92%) DAF compared to GA3. Furthermore, counting the numbers of flowers did not provide insights into the quality and quantity of pollen; the results showed that PV was highest at 18 DAF with A4; however, the number of flowers per plant was 150.33 at 18 DAF and was thus not the maximum of produced flowers within the experiment. IFC technology successfully estimated the TPC and differentiated between viable and non-viable cells over a period of 8 to 24 DAF in tested genotypes of Cannabis sativa. IFC seems to be an efficient and reliable method to estimate PV, opening new chances for plant breeding and plant production processes in cannabis.

Ethylene Acts as a Negative Regulator of the Stem-Bending Mechanism of Different Cut Snapdragon Cultivars

This study investigated whether ethylene is involved in the stem-bending mechanism of three different snapdragon cultivars ‘Asrit Red’, ‘Asrit Yellow’, and ‘Merryred Pink’, by treating their cut stems with an ethylene-releasing compound (ethephon), an ethylene-action inhibitor [silver thiosulfate (STS)], and distilled water (as the control). Ethephon completely prevented stem bending in all cultivars, whereas STS exhibited a higher bending rate compared with the control. The bending rates were influenced by several factors, such as the degree of stem curvature, relative shoot elongation, ethylene production, and lignin content, indicating their involvement in the stem-bending mechanism of the cultivars. The analysis of the expression of genes involved in the ethylene and lignin biosynthetic pathways also supported the importance of lignin and ethylene in the stem-bending mechanism. Taken together, as ethephon completely prevented stem bending of the three snapdragon cultivars, this study suggested that ethylene acts as a negative regulator of the stem-bending mechanism of snapdragon cultivars, and the information will be valuable for the prevention of stem bending in other commercially important ornamental flowers.

Effects of Polyamines And Silver Thiosulphate On Phoenix Dactylifera L. Cv. Quntar Micropropagation And Molecular Analysis.

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. The objective of the present study is to determine the effect of polyamines (putrescine "PUT" and spermidine" SPD") and silver thiosulfate (STS) on enhancing propagation of date palm cv Quntar in vitro. 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 regeneration 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.

A Cytokinin Analog Thidiazuron Suppresses Shoot Growth in Potted Rose Plants via the Gibberellic Acid Pathway

Application of thidiazuron (N-phenyl-N′-1,2,3-thiadiazol-5-ylurea, TDZ), a cytokinin analog, to inhibit the leaf yellowing that occurs after pinching potted rose plants, resulted in compact plants with shorter shoots and thicker internodes. Two weeks after treatment with 100 μM of TDZ, new shoots were half as long as those in control plants, and stem diameters were about 40% greater. This effect of TDZ is associated with changes in cell architecture. Although TDZ treatment stimulated ethylene production by the plants, inhibitors of ethylene biosynthesis (2-aminoethoxyvinyl glycine) or action (silver thiosulfate) did not affect the response of plants to TDZ. We found that TDZ treatment significantly suppressed the expression of bioactive gibberellic acid (GA) biosynthesis genes encoding GA3 and GA20 oxidases and slightly increased the expression of GA catabolism genes encoding GA2 oxidase. Application of GA3 and TDZ together resulted in normal elongation growth, although stem diameters were still somewhat thicker. Our results suggest that TDZ regulates shoot elongation and stem enlargement in potted rose plants through the modulation of bioactive GA biosynthesis.

The selective cytotoxicity of silver thiosulfate, a silver complex, on MCF-7 breast cancer cells through ROS-induced cell death

Background Silver is a transition metal that is known to be less toxic than platinum. However, only few studies have reported the anticancer effects of some silver complexes and their possibility as an alternative to platinum complex. This study investigated the anticancer effects of the silver thiosulfate complex (STS), [Ag(S2O3)2]3−, consisting of silver and sodium thiosulfate. Methods In vitro cytotoxic activity of STS was investigated comparatively in human cancer cell lines (K562 and MCF-7) and normal human cells (mesenchymal stem cells and mammary epithelial cells). For its anticancer effects, cell cycle, mode of cell death, morphological changes, and accumulation of intracellular ROS and GSH were evaluated in MCF-7 to provide mechanistic insights. Results STS showed a concentration-dependent cytotoxicity in MCF-7 cell, which was abolished by pretreatment with N-acetylcysteine, suggesting ROS accumulation by STS. Moreover, STS caused cell cycle arrest at the G1 phase, decrease in the GSH levels, and morphological changes in MCF-7. Direct measurement of ROS demonstrated the elevation of intracellular ROS accumulation in cancer cells treated with STS; however, neither cytotoxicity nor ROS accumulation was observed in normal human cells. Conclusion The results obtained here are the first evidence to show that STS exhibited an anticancer activity through ROS-induced mechanisms, and that its cytotoxicity is highly selective to cancer cells. The results of the present study warrant further investigation on the detailed mechanism of STS actions, as well as its in vivo effectiveness and safety for clinical application.

Silver thiosulfate and Benzyladenine in combination with pruning additively feminizes cassava flowers and modulates transcriptome

Cassava, a tropical storage-root crop, is a major source of food security for millions in the tropics. Cassava breeding however is hindered by the poor development of flowers and female flowers in particular, since flower development is strongly skewed towards male flowers. Our objectives were to test plant growth regulator and pruning treatments for their effectiveness in field conditions in improving flower production and fruit set in cassava. Pruning the fork type branches that arise at the shoot apex immediately below newly formed inflorescences stimulated inflorescence and floral development. The anti-ethylene silver thiosulfate (STS) also increased flower abundance. Both pruning and STS increased flower numbers without influencing sex ratios. In contrast, the cytokinin benzyladenine (BA) feminized flowers without increasing flower abundance. Combining pruning and STS treatments led to an additive increase in flower abundance; with the addition of BA, over 80% of flowers were females. This three-way treatment combination of pruning+STS+BA also led to an increase in fruit development. Transcriptomic analysis of gene expression in tissues of the apical region and developing inflorescence revealed that the enhancement of female flower development by STS+BA was accompanied by the downregulation in of several genes associated with repression of flowering, including Tempranillo 1 (TEM1), GA receptor GID1b, and ABA signaling genes ABI1 and PP2CA. We conclude that treatments with pruning, STS and BA create widespread changes on the network of hormone signaling and regulatory factors beyond ethylene and cytokinin.

Pollen Appearance and In Vitro Germination Varies for Five Strains of Female Hemp Masculinized Using Silver Thiosulfate

Genetically female seed is sought for cannabidiol (CBD) hemp production because CBD is extracted from the flowers of female hemp plants. The production of all female seed requires masculinization of female plants to produce genetically female pollen that reliably generates female seed. Of the five female hemp genotypes that we masculinized using foliar sprays of silver thiosulfate (Abacus, Cherry Wine, Mountain Mango, Youngsim10, Wife), all genotypes produced fewer large and more irregular or misshapen pollen grains than genetically male plants. The masculinized female genotypes Wife and Cherry Wine produced pollen with germination rates similar to those of the male genotype Kentucky Sunshine. Female hemp genotypes vary in their ability to produce usable pollen that disperses well, is easily collected, and germinates as well as pollen from genetically male hemp plants.