Development of the prickly pear cactus Opuntia stricta (Haw.) Haw. (Cactaceae) in vitro in response to the replacement of potassium nitrate for a commercial kno 3 fertilizer

ABSTRACT: In micropropagation, potassium nitrate (KNO3), an ACS reagent grade chemical, used in the preparation of growing mediums is expensive and its procurement depends on bureaucratic procedures, as it is controlled by the Brazilian Army. This research to assessed the effect of replacing the ACS KNO3 for a commercially available fertilizer (KNO3- based) on the micropropagation of the prickly pear cactus (Opuntia stricta (Haw.) Haw. cv. Elephant Ear. Treatments used six different fertilizer concentrations (0, 0.5, 1, 1.5, 2 and 2.5 g L-1) and a control consisting of 1.9 g L-1 KNO3, as shown in the MS salts. The survival, size and number of sprouts and the value of fresh biomass were evaluated. After seedling acclimation, we assessed the survival, number of sprouts, length, and number of roots, racket formation, average fresh biomass mass, macronutrient absorption and morphological changes of the seedlings. Explants inoculated with fertilizers at concentrations of 0.0; 2.0 and 2.5 g L-¹ did not grow. The response of explants at concentrations of 0.5 and 1.5 g L-1 of the fertilizer were the same as those developed in a KNO3 medium, and at a concentration of 1.0 g L-1, in all variables, the means were higher than those of the control medium. Therefore, it showed the feasibility of using fertilizers in the in vitro cultivation of the prickly pear cactus, which may remove bureaucratic barriers and reduce product costs by 99.12%.

Growth regulators and their reflection on different hop genotypes cultivated under in vitro conditions

Hops is a new culture in Brazil. Tissue culture can be an important technique for rapid hop propagation. This paper aims to characterize responses from different genotypes under different growth regulators through the interrelationship of response variables important to hop in vitro growth. Three genotypes were cultivated in six culture media with different combinations of growth regulators, BAP (6-benzylaminopurine), IAA (3-indolacetic acid) and GA3 (gibberellic acid). The means were compared by orthogonal contrasts and the interrelationship of the response variables was performed by path analysis. American genotypes showed favorable root development under the BAP + IAA combination, while the use of IAA improved shoot development. The origin of genotypes was important for defining the best protocol for in vitro cultivation. The path coefficient showed that the variable number of shoots has stronger direct effect on the number of nodal segments. Additionally, in tissue culture assays, the use of a covariable and proper error distribution significantly increased experimental accuracy.

THE INFLUENCE OF LIGHT QUALITY IN THE in vitro CULTIVATION OF Cattleya crispata

ABSTRACT: Micropropagation technique is a valuable alternative for high quality genetic preservation of endemic species such as the orchid Cattleya crispata from “Campo Rupestre Ferruginoso”. This study aims to evaluate the influence of light quality on in vitro multiplication and elongation phases, offering new insights on the limiting factors of C. crispata. Seeds extracted from capsules were used for inoculation in the culture medium. Four light sources were evaluated for in vitro culture, namely: fluorescent lamp, white LEDs, red LEDs and red/blue LEDs. Data about the number of shoots, shoot length, shooting vigor and pigment content were assessed at 90 days of in vitro culture. Based on the recorded results, white LEDs are the most suitable ones for in vitro multiplication and elongation phases of C. crispata. It offers higher quality for seedling production and increases the chances of genetic conservation of the species. Keywords: ‘Campo Rupestre Ferruginoso’; in vitro propagation; wavelength; LEDs.

Antiplasmodial Activities of Some Locally Prepared Herbs Against Plasmodium falciparum Obtained from Asymptomatic School Children in Zaria, Kaduna State, Nigeria

The efficacy of current or any intended antimalarial can only be resolute by cultivation and susceptibility studies. The aim of this research was to cultivate Plasmodium falciparum in vitro and comparing the antiplasmodial effects of standard antimalarial medications including herbaceous preparation. Asymptomatic pupils attending some schools in Zaria, Kaduna state, Nigeria were recruited into this research and blood samples were collected from them. Microscopy was done after thin and thick blood films were prepared and stained. The antiplasmodial activities of antimalarial drugs as well as herbal preparation were determined after the successful culturing of red blood cells in the Jatropha curcas medium.The phytochemical constituents of the herbs that made up the concoction were determined. The incidence of asymptomatic Plasmodium infection amongst school kids was 17.5%. There was no statistical association of location, gender and age with the obtained prevalence. Presence of alkaloids was observed in every plant screened while the same was also observed for tannins except in Enantia chloranta.Steroids and phlobatanins were observed in Citrus aurantifolia while there was presence of saponins in all the plant extracts except Cymbopogbon citratus. All the plants except Enantia chloranta contained flavonoids. There was presence of terpenoids in all screened plants except Azadirachta indica and Cymbopogbon citratus while cardiac glycosides were found in every plant except Magnifera indica and Enantia chloranta. Results obtained from the in vitro cultivation of the Plasmodium falciparum with Athemether/lumefanthrine, amodiaquine and herbal concoction showed average percentage parasite inhibition of 80%, 37.8% and 38.6% respectively. This implies that Arthemether/lumefanthrine was capable of inhibiting the growth of the parasite best. The herbal concoction also inhibited growth (38.6% inhibition). There is need for additional investigation on a wider variety of plants to explore their antiplasmodial activities since there is evidence that it works, and it is quite available and affordable.

Genetic Inactivation of D-Amino Acid Oxidase Genes in Methylotrophic Yeast Hansenula Polymorpha

Cellular D-amino acid oxidases (ODA-FAD containing flavoproteins) are widely used in biotechnology. In this regard, it is of particular interest to investigate the functional role of the composition and regulation of individual ODA genes. The aim of this work was to investigate physiological and biochemical characteristics of ODA genes of strain DL1x Hansenula (O.) polymorpha in vivo using gene knockout methodology as well as to determine the nature of these genes expression and regulation of ODA activity as a function of nitrogen and carbon source composition in the cultivation medium. H. polymorpha is a thermotolerant methylotrophic yeast. They are used to study the mechanisms of peroxisomal biogenesis and degradation, regulation of methanol metabolism, nitrate assimilation and stress response. A serial dilution method has been used for rapid assessment of strain growth and stress tolerance. Vector design for genetic inactivation of ODA genes in H. polymorpha was performed using yeast vector pAM773. Selection of "knockout" cell clones was performed using PCR analysis. To complete the transformation process, H. polymorpha was deleted from the pAM773 vector and the obtained DNA was used in the experiment. In vitro cultivation of knockout strains of H. polymorpha was found to exhibit substratespecificity of the ODA. According to the authors, the HP2914 gene is important for D-alanine oxidation, while the gene complex 2400 and 2914 is important for ODA activation in the presence of D-Phe in the medium. It is likely that the gene complex 2082 and 2165 regulates ODA activation when cells are cultured in medium with D-Ala and D-Asp. It was found that in the absence of 2165, 2400, 2914 genes, increased ODA activity to D-Ala only was observed in cell culture medium. The presence of D-alanine combined with 1 % glycerol and 1 % methanol in the culture medium stimulated the activity of the three major ODAs of H. polymorpha through the expression of the HP2914 gene, while the presence of glucose and L-alanine in the culture medium suppressed their activity

Micropropagation of lavender: a protocol for production of plantlets

ABSTRACT Lavender (Lavandula dentata) has several medicinal applications, both in the fresh form and after industrial processing. Productivity increase could be obtained through the mass propagation, expanding the possibility of obtaining raw material for production of essential oil. The objective of this work was to develop a micropropagation protocol from explants obtained from seeds. Aspects of in vitro germination, multiplication, elongation and rooting were evaluated and, in sequence, the acclimatization process as well. The in vitro germination of lavender seeds can be obtained using a medium composed of agar and water. For multiplication, the use of MS medium (Murashige & Skoog, 1962) added with 5.0 µM 6-benzylaminopurine to the nutrient medium is the most appropriate. For elongation and rooting, the use of growth regulators is unnecessary. Acclimatization can be obtained directly by transferring the explant to plastic bags with substrate, kept in a greenhouse. It was possible to develop a protocol for the in vitro cultivation (establishment, multiplication, elongation, rooting and acclimatization) of lavender from explants of seed origin.

Development of a method for obtaining healthy mini-tubers of potatoes of the Yubilyar variety using a humic preparation from peat

The influence of various nutrient medium compositions on the growth of potato plants during in vitro cultivation and the possibility of using biological fertilizer from peat in different concentrations to improve the adaptation of plants to growing in ground for the development of a method for obtaining healthy mini-tubers of potatoes of the Yubilyar variety were studied. The influence of various nutrient medium compositions on the height, biomass, intensity of rhizogenesis, the number of internodes of improved potato micro-plants, as well as humic fertilizer from Humostim peat on the survival rate and height of potato plants when adapting it to ground conditions is analyzed. Taking into account the data obtained, as well as the cost of the studied variants of the medium, the optimal medium for growing potato micro-plants in laboratory conditions in vitro is a nutrient medium with a content of mineral components 1/3 from the norm. The use of humic preparation from peat Humostim in a concentration of 0.001% caused an acceleration of plant growth and an increase in their height, and this concentration is recommended for use.

Study of Phytophthora infestans Mont. de Bary isolates in the planting of potatoes

Relevance. One of the most common diseases of potatoes and other nightshade family species is late blight caused by a pathogenic oomycete of the Phytophthora infestans (Mont.) de Bary. At least 100 species of phytophthora have been described in nature, affecting a wide range of plant species. The phytophthora population is heterogeneous and is represented by races, as well as different types of mating. This leads to a rapid adaptation of the pathogen and the emergence of new, more aggressive, and resistant races. Phytophthora is a parasite, the damage from which cannot be avoided within the organic farming framework. Therefore, it is particularly important to know the pathogenesis and racial composition of phytophthora in each individual region of Solanaceae cultivation.Research methodology. Differentiation and collection of material from the natural population were carried out using potato varieties with known R-genes in the genome. Isolation and introduction into the culture were carried out from leaves with the dampening chambers method, followed by cultivation on nutrient media. The pathogen was identified by microscopic analysis. Culture filtrates were obtained on the liquid nutritious medium, followed by liquid filtration and autoclaving. Phytotoxic activity was determined by the effect on the seedlings of the nightshade, grass, and pea families by the standard method. Molecular genetic analysis of the isolates was carried out by ISSR analysis; the primer, amplification mixture, and temperature profile of the reaction were selected according to the literature data; the calculation of genetic characteristics was carried out using POPGENE software packages.Results. Samples of seven Phytophthora infestans isolates were collected and introduced into culture. As a result of in vitro cultivation, morphological differences were revealed, expressed in the structure and color of the mycelium, the shape of the colonies, the nature of sporulation, the color of the reverse, and the medium under the colonies. The genetic differences of the natural phytophthora material introduced into the culture, collected from potato varieties with single resistance genes (R1, R3, R4), were revealed. Differences in the phytotoxic activity of the studied isolates' cultural filtrates were revealed. The isolated isolates demonstrate differentiation at the phenotypic, genetic and physiological levels, which allows us to speak about their belonging to races.