Efecto de la desinfección, el desarrollo foliar y las fitohormonas en la inducción de callos de Simarouba amara Aubl.

Aims: This work aims to evaluate the influence of different growth regulators combined with antioxidants on the induction of callus with different explants in cashew.
 Materials and Methods: Nucellar tissues, cotyledons and testa from elite tree nuts are cultured on media that differ in their concentration of 6-Benzylaminopurine (BAP: 0 mg/l; 0.25 mg/l; 0.5 mg/l) and Acid 2,4 dichlorophenoxyacetic (2,4-D: 0 mg/l; 0.8 mg/l). Therefore, for the control of the browning of the explants, the effect of activated charcoal and polyvinylpyrrolidone was tested. The amount of callus formed is evaluated after 28 days and after 90 days by simple observation according to a given scale. 
 Results: Analysis of variance of callus formation 28 days after the culture of explants shows that the interaction between growth regulators and antioxidants significantly influences (p < 0.05) the induction of callus. The combination BAP 0.25mg/l and 2,4-D 0.8mg/l produces on average more callus (0.47 ± 0.00). There is a very significant difference (P < 0.05 to p<0.001) in the effect of growth regulators and antioxidants on obtaining callus after 90 days of cultivation. The 0.25 mg/l combination of BAP and 0.8 mg/l of 2,4-D still appears to be the best combination of growth regulators for callus with 58% of callus formed. Cotyledons in the presence of PVP respond better than activated charcoal. The nucellus are the explants that respond better in the presence of activated charcoal. The test for Least Significant Difference reveals that PVP significantly promotes (p <0.05) the production of a large number of calli (77%) unlike activated charcoal (9%) after 90 days of culture.
 Conclusion: Summary, for obtaining viable and embryogenic callus in cashew, the combination of BAP at 0.25 mg/L and 0.8 mg/L of 2,4-D is the best and this in the presence of PVP with cotyledons.

Haploid and doubled haploid lines can be obtained in a short time using in vitro methods. In this study, unfertilized ovaries of cucumber were harvested and placed on semi-solid MS media as explants in Petri dishes. The thermal shock pretreatment, cucumber genotypes, hormonal combinations and AgNO3 were evaluated as experimental factors in three consecutive experiments. The results of first experiment revealed that the thermal shock pretreatment had a significant influence on embryo induction, and the highest rate of embryogenesis was produced in presence of thermal shock pretreatment and the NAA+2,4-D+KIN+BAP (0.5+0.7+1+1.8) mg/L hormonal combination. The highest rate of callus induction was recorded in combination of absence thermal shock and the NAA+2,4-D+KIN+BAP (1.5+0.7+1+1.8) mg/L hormonal combination. According to the second experiment results, genotypes and the other hormonal combinations in media culture had highly significant effects on embryo and callus induction. The NBDC6*6/32441 genotype had the highest effects on these traits. A combination of BAP (4 mg/L) and 2,4-D (1.5 mg/L) was found to be optimal for embryogenesis. In third experiment, the highest level of embryogenesis (24.93%) and callus (24.19%) induction were found in the local Iranian cultivar in comparison to NBDC6*6/32441 genotype. Silver nitrate treatment had significant effects on the embryo and callus induction. The highest rate of embryo induction was recorded in presence of silver nitrate; however the absence of AgNO3 had a positive effect on the callus induction. In conclusion, the thermal shock pretreatment, silver nitrate, genotype and hormonal combination factors could play key roles in embryo and callus production, independently and simultaneously.

Various food products distributed throughout the cold chain can present a health risk for consumers due to the presence of psychrotolerant B. cereus group species that possess enterotoxin genes and antibiotic resistance. As these bacteria can grow at the low temperatures used in the food industry, this study evaluated the antimicrobial efficacy of acetic acid, sodium hypochlorite, and thermal treatments for inhibition of psychrotolerant strains and the effect that differences in activation temperature (30 °C and 10 °C) have on their efficacy. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and bacterial growth assay of acetic acid and thermal treatment showed an equal or higher antimicrobial efficacy in isolates activated at 10 °C than in those activated at 30 °C. In particular, psychrotolerant strains from the B. cereus group were completely eliminated with 0.25% acetic acid, regardless of the activation temperature. The possibility of tolerance was determined by observing responses in cells activated at 10 and 30 °C when exposed to different concentrations of sodium hypochlorite. Five isolates activated at 10 °C exhibited enhanced survivability in sodium hypochlorite compared to isolates activated at 30 °C, and these isolates were able to grow in sodium hypochlorite at concentrations of 250 ppm or higher. Although a significant difference in antimicrobial efficacy was observed for psychrotolerant B. cereus group strains depending on the activation temperature, acetic acid may be the most effective antimicrobial agent against psychrotolerant B. cereus species isolated from food products distributed in a cold chain.

Bacterial blight is a serious disease of carrot production worldwide. Under favorable conditions, the causal organism Xanthomonas hortorum pv. carotae causes serious loss especially in seed production because of its seed-borne character. Unlike fungal diseases, the treatment of bacterial diseases is limited and methods such as hot water or sodium hypochlorite (bleach) treatment are mainly used by seed companies. Here, we compared the efficacy of hot water treatment, sodium hypochlorite treatment and treatment with three phenolic compounds-carvacrol, thymol and eugenol, to eliminate Xanthomonas growth in vitro and subsequently in vivo on seeds of Xhc low, medium and highly infested carrot seed lots. The complete elimination of Xhc from germinated plants was obtained only for Xhc low infested seed lot with 1% sodium hypochlorite and carvacrol solutions in concentrations of 0.0196%- 0.313%. The significant reduction of Xhc presence in germinated plants of Xhc medium infested seed lot was achieved with 1% sodium hypochlorite treatment and hot water treatment. However, hot water treatment resulted in a significant reduction of seed germination percentage as well. Considering the elimination of Xhc infection from germinated plants and the effect on seed germination and plant vigor, 0.0196% carvacrol solution was suggested as an alternative to 1% sodium hypochlorite treatment regarding additional costs related to the liquidation of used treated water and to hot water treatment that has been proved to be insufficient to obtain disease-free plants.

Celery (Apium graveolens L.) belongs to the Apiaceae family and biennial herbs. Celery is an important vegetable that is cultivated and consumed worldwide. Celery leaves, particularly the petioles, are the main edible parts. Seven genes (AgTCP1, AgTCP2, AgTCP3, AgTCP4, AgDELLA, AgLEP, and AgARGOS) that are involved in leaf growth and development were cloned from two celery cultivars (‘Liuhehuangxinqin’ and ‘Ventura’). The expression profiles of these genes were determined in different tissues and at three stages of leaf growth and development. Then, the petioles and leaf blades at the three stages were anatomically characterized. Results demonstrated that the seven genes were expressed in all tissues. The highest expression of all genes, except for AgLEP and AgTCP2, was found in the leaf blades, followed by the root, stem, and petioles. The relative expression of the genes in the petioles and leaf blades increased during the three stages. Higher gene expression was detected in ‘Ventura’ than in ‘Liuhehuangxinqin’. From Stage 1 to Stage 3, the collenchyma and vascular bundles of the petioles and leaf blades developed to be thick and large, the phloem and xylem developed extensively, and the cells grew large and tightly arranged. The growth and development of ‘Ventura’ were faster than those of ‘Liuhehuangxinqin’. The expression profiles of the seven genes (AgTCP1, AgTCP2, AgTCP3, AgTCP4, AgDELLA, AgLEP, and AgARGOS) and the anatomic characteristics of the petioles and leaf blades were used as bases to identify the related functions of potential genes at the different stages of leaf growth and development in celery. This study provided insights into the leaf regulation mechanism and development in the Apiaceae plant.

Improvement of sugarcane through conventional breeding takes longer time (8-10 years) to release new improved genotypes. Callus induction and regeneration protocol is a prerequisite for genetic improvement through genetic engineering. Hence, this study was initiated to develop a protocol for in vitro callus induction and regeneration of three sugarcane genotypes (C86-56, C132-81 and SP70-1284) using immature young leaf as a source of explants. Seed cane of 30 cm size having 2 nodes each were obtained from Metehara Research and Development, operating under Ethiopian Sugar Corporation. They were then brought to the National Agricultural Biotechnology Research center and planted in the greenhouse to serve as sources of explants. The treatments were arranged in a factorial experiment laid out in a completely randomized design. For callus induction MS medium supplemented with five levels of 2,4-D (2.0, 2.5, 3.0, 3.5 and 4.0 mg/l) was used. Immature leaves were collected from the green house grown plants 3 months after planting and were cultured on callus induction medium after sterilizing with 5% berekina for 15 minutes and then followed by 70% alcohol for 30 seconds under the biological safety cabinet. For plant regeneration four levels of BAP (0.5, 1.0, 1.5 and 2.0 mg/l) were used in combination with four levels of IBA (0.0, 0.25, 0.5 and 0.75 mg/l). Callus induction experiment was replicated four times and each replicate was represented by four explants per a culture jar and shoot regeneration experiment was replicated three times, 2 embryogenic calli per jar each for regeneration. Data were recorded for all parameters and analyzed using Statistical Analysis System (SAS) Software version 9.3. Means were separated using least significant differences (LSD) at 0.001 probability level. Analyses of variance indicated that days to callus initiation, frequency of callus induction and callus weight were affected significantly (p≤0.001) by genotype, 2, 4-D levels and their interaction. Genotype C132-81 was identified as the best for early callus initiation, high frequency of callus and callus weight. The highest percentage (92.31%) of callus initiation was recorded on medium supplemented with 3.0 mg/l of 2,4-D with higher callus weight (454.5 mg). Regeneration percentage, number of shoots, shoot length and number of leaves per shoot were also significantly (p≤0.001) affected by genotype, BAP, IBA and their interaction effect. Genotype C132-81 also recorded significantly higher number of shoots (43.44±0.5) on MS medium supplemented with 1 mg/l BAP in combination with 0.5 mg/l IBA. Genotype C86-56 gave higher shoot length (6.38±0.08) cm while C132-81 gave the higher number of leaves (8.24±0.06) at 2.0 mg/l BAP+0.25 mg/l IBA. In conclusion, 3.0 mg/l and 3.5 mg/l 2,4-D concentrations were found optimum for callus induction and development, while 1.5 mg/l BAP+0.5 mg/l IBA was the best for plant regeneration. Keywords : genotype, explant, callus induction, regeneration DOI: 10.7176/JBAH/11-3-05 Publication date: February 28 th 2021

In modern plant breeding, anther culture is an important biotechnological tool that shortens the breeding cycle and improves efficiency, thereby playing a crucial role in genetic improvement and cultivar development. To date, there have been few studies on anther culture in daylily (Hemerocallis spp.). The present study aimed to investigate the effects of the microspore developmental stage, low-temperature pretreatment duration, and phytohormone combinations on callus induction and plant regeneration from daylily anthers. We first studied the morphological characteristics of flower buds and anthers at different microspore developmental stages, and then used anthers from different developmental stages for callus induction. The results showed that microspores at the late uninucleate stage were optimal for callus induction. Low-temperature pretreatment at 4°C for 24h could effectively promote the formation of callus tissue in daylily anthers. In the (L9(34)) orthogonal array experiment, the callus induction rate was highest (45.57%) in the medium containing MS (Murashige and Skoog) + 70g/L sucrose + 2mg/L Kn (Kinetin) + 2mg/L 2,4-D (2,4-dichlorophenoxyacetic acid) + 0.1mg/L NAA (1-naphthaleneacetic acid). Among the nine media for callus bud differentiation, the highest adventitious bud induction rate was achieved with MS + 30g/L sucrose + 2mg/L 6-BA (N6-benzyladenine) + 0.1mg/L NAA (43.33%). The optimal rooting medium was MS + 30g/L sucrose + 0.05mg/L NAA + 0.1mg/L IBA (Indole- 3-butyric acid) (93.33%). Flow cytometry and Simple sequence repeats (SSR) analysis showed that all 55 intact plantlets derived from anthers were diploid. This study optimized the anther culture technique for daylily and proposed a comprehensive anther culture method for callus induction and plant regeneration. For the first time, plant regeneration was achieved via anther culture in daylily, providing relevant theoretical and technical support for genetic research and daylily breeding.

Since silicon regulates plant physiological and biochemical processes, it was hypothesized that foliar silicon application could contribute to improving the quality of new potatoes. This paper analyzes the effect of silicon (sodium silicate) on the nutritional value and sensory quality of new potatoes. Silicon was applied at the dose of 23.25 g Si·ha−1 or 46.50 g Si·ha−1 once at the leaf development stage (BBCH 14–16) or at the tuber initiation stage (BBCH 40–41) and twice, at the leaf development and tuber initiation stages. Potatoes were harvested 75 days after planting (the end of June). Silicon had no effect on the dry matter, total sugars and monosaccharides, protein, L-ascorbic acid or nitrate content in new potato tubers, but it increased the starch content under water deficit conditions. The most starch was accumulated by tubers following the application of 46.50 g Si·ha−1 at the leaf development stage (BBCH 14–16). Silicon did not affect the color of tuber flesh after cooking.

Since silicon can improve nutrient uptake in plants, the effect of foliar silicon (sodium metasilicate) application on micronutrient content in early crop potato tuber was investigated. Silicon was applied at dosages of 23.25 g Si∙ha–1 or 46.50 g Si∙ha–1 (0.25 L∙ha–1 or 0.50 L∙ha–1 of Optysil) once at the leaf development stage (BBCH 14–16), or at the tuber initiation stage (BBCH 40–1), and twice, at the leaf development and tuber initiation stages. Potatoes were harvested 75 days after planting (the end of June). Foliar-applied silicon reduced the Fe concentration and increased Cu and Mn concentrations in early crop potato tubers under water deficit conditions but did not affect the Zn, B, or Si concentrations. The dosage and time of silicon application slightly affected the Fe and Cu concentration in the tubers. Under drought conditions, the highest Mn content in the tuber was observed when 46.50 g Si∙ha–1 was applied at the leaf development stage, whereas under periodic water deficits, it was highest with the application of the same silicon dosage at the tuber initiation stage (BBCH 40–41). The Si content in tubers was negatively correlated with the Fe and B content, and positively correlated with the Cu and Mn content.

Cananga odorata (ylang-ylang) is a plant with numerous uses, including ornamental use, traditional medicinal ingredient, as fragrance, and cosmetics. The high market demand for ylang-ylang essential oil needs to be supported by information on the in vitro process of callus formation to supports the secondary metabolites production without having to cut or harvest the trees so that biodiversity is maintained. The aims of this study were to analyze the explants sterilization method using sodium hypochlorite (NaOCl) solution that was most suitable for the ylang-ylang initiation, and to analyze the effect of BAP and NAA treatment on the formation of ylang-ylang callus. The design used is a completely randomized design. The methods used included the preparation, sterilization, and callus induction using a combination of BAP and NAA hormones with twenty four treatment combinations. The results are: the sterilization of explants with sodium hypochlorite (NaOCl) solution at a concentration of 20% (v/v) 10 minutes followed by a concentration of 15% (v/v) 20 minutes was able to produce sterile explants in as much as 67.5% of cases. At the callus induction stage, the highest score of callus formation in leaf explants was in media-23 (BAP 4 ppm plus NAA 5 ppm).

Colour fading is a method that is used to achieve a vintage look in textile goods. It is desired by customers in the textile market. Additionally, customers demand that these types of products are produced by environmentally friendly methods. In this study, sodium hypochlorite and ozone were used as laboratory‐scale colour fading reagents on dyed cotton fabrics. Cotton fabrics were dyed with four different primary colours: red, yellow, blue and black. Dyed fabrics were subjected to ozone and sodium hypochlorite treatment under different treatment conditions. Ozone was chosen as an alternative for comparison and it was applied at fixed flow rate (5 L/min) and time (10 minutes). Colour differences, chemical oxygen demand, bursting strength and energy, water and chemical consumptions were measured. The surface morphology was characterised by scanning electron microscopy. We can conclude that ozonation is effective in discharging colour from dyed fabric samples, and the colour‐fading effect is uniform, like in sodium hypochlorite treatment. It was observed that both processes are similar in terms of strength and surface modification. Results showed a 90% cost reduction, 85% water conservation and a 26% chemical oxygen demand reduction.

Cinchona officinalis L., considerada una especie iconica del Ecuador, fue explotada durante el siglo XVIII el cultivo hasta el XIX que la llevo casi a la extincion. Hoy en dia, utilizando como herramienta el cultivo de tejidos vegetales se puede dar solucion a problemas naturales y/o inducidos en algunas especies forestales nativas, como el caso de Cinchona. Asi, la presente investigacion desarrollada en el Laboratorio de Micropropagacion Vegetal de la Universidad Nacional de Loja durante el ano 2016, consistio en generar informacion sobre los procesos biotecnologicos que permitan la propagacion in vitro de Cinchona officinalis L., en sus fases de: implantacion, induccion de callos e induccion de embriones. Se utilizo el medio de cultivo basal de Murashige & Skoog (MS) suplementado con vitaminas y hormonas. Se aplico un diseno completamente al azar, analizado por medio de un ANAVA con prueba estadistica de LSD Fisher. Para la desinfeccion de semillas, en la fase de implantacion, se aplico hipoclorito de sodio y peroxido de hidrogeno, donde los dos desinfectantes controlaron eficientemente la contaminacion; mientras, en el ensayo de germinacion el efecto de desinfeccion mas la adicion de AG3 al MS liquido resulto efectiva. En la fase de induccion de callos, los segmentos nodales se cultivaron en medio MS solido, suplementado con auxinas y citoquininas; logrando los mejores resultados en la combinacion hormonal. En la fase de induccion de embriones, los explantes se cultivaron en medio de MS solido suplementado con auxinas y citoquininas en diferentes concentraciones

Catechins, a group of polyphenolic compounds in the green leaf of tea [Camellia sinensis (L.) O. Kuntze], are major components conferring quality attributes and health benefits on processed tea. Expression patterns of the basic genes related to accumulation of the catechins and total polyphenols at different stages of tea leaf development and their relationship with catechin concentration were investigated by reverse transcriptase polymerase chain reaction and high‐performance liquid chromatographic methods. The results showed that the concentration of total catechins and polyphenols in leaves at different stages of development declined with age of the leaf but changes of the individual catechins varied, with a general decrease in catechin gallate and epigallocatechin gallate and increase in epigallocatechin and epicatechin gallate. Genes of phenylalanine ammonium lyase (PAL), dihydroflavonol reductase (DFR) and three chalcone synthase genes (CHS1, CHS2, CHS3) were highly expressed in bud, first leaf and second leaf but were barely detected in mature leaves. The expression of DFR, a downstream gene in the catechin biosynthesis pathway, was closely related to the concentration of total catechins and polyphenols in various stages of leaf development. Copyright © 2005 Society of Chemical Industry

Summary Plants protect themselves against potentially harmful UV-B radiation mainly by epidermal accumulation of UV-B shielding phenolic compounds and repair of cellular damage. The capacity and necessity for these protection mechanisms alter with the stage of plant and leaf development, which might be crucial for horticultural hardening techniques aiming at a UV-B pre-acclimation of greenhouse grown seedlings before transplantation to the field. In order to examine the development-dependence of UV-B responses and to estimate the efficiency of different hardening strategies, lettuce ( Lactuca sativa L., var. crispa L. 'Bughatti') was raised in greenhouses covered with a UV-B transmitting and a UV-B excluding covering material and transferred from one treatment to the other at the age of 20 days. Plant fresh mass and flavonoid content were frequently determined. Distribution of flavonoids within the plants was assessed by extraction of different leafage classes. Continuous exposure to near ambient UV-B induced a strong enhancement in cyanidin and quercetin content and a severe growth reduction, whereas late UV-B treatment merely led to a slight enhancement of quercetin in the absence of any growth response. At the leaf level, continuous UV-B exposure caused a comparable quercetin induction at all three stages of leaf development, whereas late treatment caused a much stronger response in young compared to intermediate and old leaves. These findings indicate that UV-B effects on growth and flavonoid content and pattern of lettuce plants are highly dependent on the leaf and plant developmental stage. We conclude that UV-B exposure throughout seedling development is a more efficient hardening strategy than late short-term exposure.

The 84K poplar (Populus alba × Populus glandulosa) is a fast-growing hybrid poplar that was introduced from South Korea by the Chinese Academy of Forestry in 1984. To gain deeper insight into the regulatory mechanisms of leaf development in 84K poplar, we performed bulk RNA sequencing and found that numerous members of the AP2/EREBP family exhibited expression changes, suggesting their crucial roles in leaf development. The AP2/EREBP transcription factor family is one of the largest and most conserved gene families in plants. These genes play a crucial role in plant growth, development, and stress responses. In this study, we identified and analyzed 400 AP2/EREBP genes through transcriptome analysis, excluding genes with missing values (NAs) or FPKM < 1, and selected 76 genes based on their expression patterns at different stages of leaf development. The 76 genes were classified into three subfamilies based on phylogenetic analysis and structural domain characteristics: the RAV subfamily, the ERF subfamily, and the AP2 subfamily. Each subfamily shares similar gene structures and motifs while also exhibiting distinct differences. Segmental duplication events may have contributed to the evolution of this gene family. Most of the promoter cis-acting elements are related to light responses, with fewer elements associated with palisade tissues and hormones. Eight genes, selected for their gradually decreasing expression during leaf development, were validated through RT-PCR experiments. Among them, five genes—Pop_G10G022861, Pop_A01G003858, Pop_A01G081120, Pop_A01G074798, and Pop_A07G010900—exhibited a decreasing trend in expression across the three stages of leaf development. Subcellular localization analysis indicated that Pop_A01G003858 and Pop_G11G077730, two randomly selected genes from the eight AP2/EREBP members validated by RT-PCR, are localized in the nucleus. In conclusion, these findings provide valuable insights into the evolutionary relationships of the 73 AP2/EREBP family members in 84K poplar leaves and lay a foundation for future studies on leaf development.