Explore the vast range of titles available.

Leaf abscission of rose (Rosa hybrida L. ‘Baby Love’) cultured in vitro due to ethylene gas accumulation and enzymatic hydrolytic activity, is one of the abnormal phenomena affecting the shoots quality. In this study, silver nanoparticles (AgNPs) and cobalt nanoparticles (CoNPs) were used to overcome leaves abscission as well as, the effect of shoot mass propagation, rooting and acclimatization at the nursery stage. The results showed that shoots cultured on MS (Murashige and Skoog, in Physiol Plantarum 15(3):473–497, 10.1111/j.1399-3054.1962.tb08052.x, 1962) medium supplemented with 2 mg/L AgNPs gave the highest shoot multiplication coefficient, shoot height, fresh weight, dry weight and chlorophyll index (5.33 shoots; 3.06 cm; 451.00 mg; 58.33 mg; 32.28; respectively) than CoNPs (replace CoCl2 in the MS medium) and basal MS medium. Meanwhile in the rooting stage, MS medium added of 4.65 µg/L CoNPs was the most optimal with dry mass ratio (10.28%), number of roots (5.67 roots), root length (2.17 cm) and SPAD (41.07 nmol/cm2) as well as reduced the ethylene gas content (0.11 ppm) and enzymes activity such as pectinase (0.07 UI/mL) and cellulase (0.25 UI/mL) in comparision to the other treatments after 4 weeks culture. The plantlets derived from in vitro culture on medium added 4.65 µg/L CoNPs gave the highest survival rate (96.67%) as well as growth and development at the nursery stage.Key messageCobalt and silver nanoparticles (CoNPs, AgNPs) were used to overcome leaf abscission, enhance growth and increase the survival rate of plantlets at the nursery stage. CoNPs helps reduce the ethylene gas content, enzymatic hydrolytic activity such as pectinase and cellulase. AgNPs was the most suitable factor for shoots mass propagation.

One of the common problems in strawberry (Fragaria × ananassa) micropropagation is the vitrification phenomenon (succulent plantlets, brittle stems, yellow leaves, etc.) leading to the reduction of plantlets quality and low survival rate in the greenhouse. In this study, the effects of silver nanoparticles (AgNPs) on explant disinfection, in vitro growth (shoot multiplication, and root formation), runner formation as well as ethylene accumulation during micropropagation of strawberry were investigated. The results showed that leaf explants treated with 200 mg/L AgNPs solution for 20 min was more effective in explant disinfection and shoot regeneration than using 1 g/L HgCl2. In addition, AgNPs stimulated the growth of shoot and plantlet and as well shortened the duration of root formation (4 days) as compared to those in control without AgNPs during micropropagation. Besides, AgNPs reduced the ethylene gas accumulation in the culture’s vessels of shoots (0.66 ppm) and plants (0.06 ppm) compared to controls (1.77 ppm; 0.15 ppm; respectively). Moreover, AgNPs combination with culture period (5; 10 or 15 days) effect root formation stage and acclimatization in the greenhouse. The plantlets that cultured on MS medium supplemethed with 0.5 mg/L AgNPs during 10 days showed higher survival rate (93.33%) after 15 days as well as runner formation per plant (8.00 runners) after 60 days in greenhouse than those in control.Key messageAgNPs improved explant disinfection and in vitro growth. AgNPs improved runner formation in the greenhouse. AgNPs limited ethylene accumulation during micropropagation.

A previously healthy 10-year-old girl developed painless visual loss. She was diagnosed with a spasm of accommodation confirmed by cycloplegic refraction. She was prescribed low-dose atropine and again reported acute visual loss that was inconsistent with the level of daily function. She was referred to a pediatric psychiatrist with suspicion for a nonorganic visual disorder and was diagnosed with conversion disorder. She received psychotherapy and continued the treatment with low-dose atropine. Her visual acuity at distance returned to normal. Psychogenic visual loss can mimic organic disorders; hence, ophthalmologists should be aware of cases without the agreement between visual signs and daily manifestation.

Land use land cover (LULC) maps are crucial for various applications, such as disaster management, natural resource conservation, biodiversity evaluation, climate modeling, etc. The Japan Aerospace Exploration Agency (JAXA) has released several high-resolution LULC maps for national and regional scales. Vietnam, due to its rich biodiversity and cultural diversity, is a target country for the production of high-resolution LULC maps. This study introduces a high-resolution and high-accuracy LULC map for Vietnam, utilizing a CNN approach that performs convolution over a time-feature domain instead of the typical geospatial domain employed by conventional CNNs. By using multi-temporal data spanning 6 seasons, the produced LULC map achieved a high overall accuracy of 90.5% ± 1.2%, surpassing other 10-meter LULC maps for Vietnam in terms of accuracy and/or the ability to capture detailed features. In addition, a straightforward and practical approach was proposed for generating cloud-free multi-temporal Sentinel-2 images, particularly suitable for cloudy regions. This study marks the first implementation of the time-feature CNN approach for the creation of a high-accuracy LULC map in a tropical cloudy country.

The acclimatization stress is responsible for high mortality in tissue cultured plants, which significantly reduces micropropagation efficiency. In this initial study, selenium nanoparticles (SeNPs) (0.1, 0.3, 0.5, 0.7, 1, 1.5 and 3 mg/L) were supplemented in gerbera culture medium to increase their tolerance to ex vitro stresses. The results revealed that SeNPs were potential gerbera rooting inducers via increasing endogenous auxin (AUX) levels. Accordingly, rooting efficiency on MS medium supplemented with 0.7, 1 and 1.5 mg/L SeNPs was similar to treatment 1 mg/L IBA and was significantly higher than the free-auxin/SeNPs treatment. At concentrations of 0.1 to 1.5 mg/L SeNPs promoted in vitro plantlet growth such as plant height, leaf length, total chlorophyll content, plantlet biomass, which corresponds to high activity of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) as well as high levels of AUX, cytokinins (CKs) and gibberellin (GA). Furthermore, it is likely that SeNPs increased stomatal density via increased CKs and decreased stomatal aperture via increased abscisic acid (ABA). The stomatal density in 0.7 mg/L SeNPs treatment (473.58 stomata.mm−2) was 2.34-fold higher than 1 mg/L IBA treatment while stomatal aperture was significantly reduced compared to control treatments. However, SeNPs showed inhibitory activity at 3 mg/L with a decrease in shoot–root growth as well as stomatal closure compared with the other treatments. This study indicated that SeNPs improved gerbera plantlet quality by promoting antioxidant defense system activity and endogenous hormone alterations, which resulted in their higher survival and growth under ex vitro conditions.Key MessageSupplementation of SeNPs in culture medium positively effects on in vitro rooting, stomatal development and biochemical parameters of in vitro gerbera plantlets, conferring their high survival rates and accelerated flowering under ex vitro conditions.

Effects of silver nanoparticles (AgNPs) on somatic embryogenesis and plantlets with rhizome of Panax vietnamensis were presented in this study. The highest number of somatic embryos (140) was obtained on MS medium containing 1 mg/L 2.4-D, 0.5 mg/L NAA, 0.2 mg/L Kin and 1.6 mg/L AgNPs. Plantlets with rhizome growth enhanced on SH medium supplemented with 1 mg/L NAA and 1.2 mg/L AgNPs and limited the ethylene gas content in the culture flasks. A low concentration of ethylene gas (0.92 ppm) stimulated plantlets with rhizome growth and development, and provided positive effect on the formation and quality of plantlets. The rhizome size of the plantlets in 1.2 mg/L AgNPs treatment was larger than those in the control without AgNPs. Plantlets acclimatized on the soilless substrate were higher survival rate (93.65%) as compared to the control (44.44%) after one year in the greenhouse. In particular, the rhizome saponin content was doubled compared with that in the planlets without AgNPs after 4-year planting in the greenhouse. These results may be scaled up for micropropagation of this important medicinal plant.Key MessageAgNPs improved somatic embryogenesis. AgNPs enhanced plantlets with rhizome. AgNPs limited ethylene accumulation during micropropagation. AgNPs increased the survival rate of plantlets with rhizome in the greenhouse. AgNPs increased saponin content of plantlets with rhizome.

Micropropagation has proven to be an effective method for large-scale plant production in a short time and a useful tool for plant breeding. Microbial contamination is one of the most difficult micropropagation challenges, resulting in reduced plant quality and loss of valuable stocks. Therefore, sterilization of culture media is a critical step in plant micropropagation. However, sterilized media might reduce the activity of plant growth regulators and nutritional components of culture media. The sterilization effects of silver nanoparticles (AgNP) on the growth of expiants and culture media were examined. The treatment with 250 ppm AgNP for 15 to 20 min of 4-wk-old ex vitro leaves proved optimal for controlling the contamination. Furthermore, the Murashige and Skoog medium containing 4 ppm AgNP resulted in 100% medium disinfection (no contamination) after 4 wk of culture. The plantlets obtained from non-sterilized MS medium (NoM) containing 4 ppm AgNP and 4 g L⁻¹ agar gave similar results as the control medium with 8 g L⁻¹ agar and the absence of AgNP. Large scale culture systems using NoM in large plastic containers of two different sizes (NoM1 and NoM2) could produce quality plantlets. Chrysanthemum plantlets in the NoM1 system showed higher antioxidant enzyme activities of ascorbate peroxidase and Superoxide dismutase than plantlets in the autoclaved medium. Furthermore, the plantlets from NoM were better acclimatized under greenhouse conditions than those from the autoclaved medium (AuM) system. The developmental stages (flower buds and blooming time) of NoM1 and NoM2 plantlets, were 1 wk earlier than those from the AuM system. The successful use of AgNP as a sterilizer and as a component of culture media would reduce the cost of micropropagation and improve plants' quality.

The sterilization effectiveness of copper nanoparticles (CuNPs) replaced common disinfectants such as mercury chloride (HgCl2) or calcium hypochlorite (Ca(ClO)2) on different explants (petioles—P, inflorescence—F and stem nodes—S) of ex vitro tuberous begonias (Begonia × tuberhybrida Voss) was investigated. Subsequently, the P, F and S explants were cut transversely into thin cell layer (tTCL) approximately 1 mm in length (P-tTCL, F-tTCL and S-tTCL) and cultured on SE induction medium in order to investigate the effect of disinfectants on somatic embryogenesis, somatic embryo morphology, antioxidant activity (Catalase—CAT and Ascorbate Peroxidase—APX), and carbohydrate content (sugar and starch) of somatic embryos and their subsequent growth. The results showed that CuNPs can replace HgCl2 and Ca(ClO)2 and are effective in surface disinfection of P, F and S explants. CuNPs enhanced embyrogenic callus and somatic embryogenesis of treated explants compared to those on HgCl2 and Ca(ClO)2. CuNP-treated F-tTCL and S-tTCL explants recorded the highest number of somatic embryos (38.00–36.67 embryos, respectively) as well as the percentage of somatic embryos in cotyledon-shape (47.37–49.09%, respectively). Moreover, the antioxidant enzyme activity (CAT and APX) and starch content of somatic embryo clusters derived from CuNPs-treated F-tTCL and S-tTCL explants were higher and the sugar content was lower as compared to those sterilizated with HgCl2 or Ca(ClO)2. Plantlets derived from different different disinfectant treatments showed no difference in morphology, in vitro rooting and acclimatization stages in the greenhouse.Key messageSurface disinfection efficiency of CuNPs on ex vitro begonia explants compared to those of common disinfectants.CuNPs effected on somatic embryogenesis, antioxidant activity, carbohydrate content.

In the present study, the positive effects of AgNPs were demonstrated for adventitious shoot formation, in vitro flowering and fruiting of Passiflora edulis Sims f. edulis—an important commercial crop. The results showed that shoot regeneration from lTCL (87.67%) and oTCL (100%) explants were significantly improved on the medium supplemented AgNPs. The in vitro shoots derived from TCL explants were used for shoot multiplication. The treatment with 1.0 mg/L meta-topolin (mT) and 5 mg/L AgNPs enhanced the shoot multiplication with the highest number of shoots (13.67 shoots/explant), shoot height (4.33 cm), and total chlorophyll content (33.93 nmol/cm2). For flowering induction, shoot tips cultured in MS medium supplemented with 7 mg/L AgNPs gave the highest of flowering rate (51.67%) and number of flowers per shoot (2.33 flowers) after 60 days of culture. In addition, shoots cultured in medium supplemented with 7 mg/L AgNPs showed significantly lower endogenous hormone of GA3, ABA, and melatonin levels than the control. In the treatment with 7 mg/L AgNPs, the flower bloom rate was 100% and the flower diameter was the largest (3.43 cm). The in vitro developed flowers self-fertilized and formed fruits. After 90 days of culture, the treatment supplemented with 7 mg/L AgNPs gave the highest fruiting rate (56.67%), number of fruits (1.67 fruits), and fruit diameter (1.13 cm). These findings pave the way for further research into flowering and fruiting mechanisms, as well as improving the efficient breeding process of this plant.Key messageA first procedure has been established for in vitro flowering and fruiting of purple passion fruit via the application of nanotechnology and the thin cell layer technique. Silver nanoparticles significantly improved shoot formation, in vitro flowering and fruiting of purple passion fruit.

Saponin compounds released by Panax vietnamensis into the rhizosphere play critical roles in drug discovery. This study investigated the growth and saponin accumulation of P. vietnamensis adventitious root. Results showed the root growth and productivity of three-saponins (MR 2 , Rb 1 , and Rg 1 ) were increased highest on the modified MS medium containing 7 mg/L IBA and 0.5 mg/L BA at 56 days. The root culture divided into three phases: (1) Growth phase 14–56 culture-days; (2) Stationary phase 56–70 days; and (3) Decline phase after 70 days. Saponin accumulation was significantly increased in the treatments of three plant-hormone-elicitors (JA, ABA, and SA), and two cell-wall elicitors (YE and CHN), but five elicitors inhibited formation lateral roots. Although contents of Rg 1 (0.32%), Rb 1 (0.85%), and MR 2 (2.83%) were highest in JA treatment at 0.48 mM, 0.24 mM, and 0.96 mM JA respectively, maximum biomass as well as saponins productivity was observed in 150 mg/L YE. In addition, combination of YE and SA showed effective lower than the solitary YE treatment. The results suggest that adventitious root biomass of P. vietnamensis developed effectively in the modified MS medium after 56 days, and the culture could be scale-up in bioreactor 20 L.