Rooting Medium Research Articles

Studies on the induction of basal stem cluster buds and nodes propagation of Amomum villosum Lour.

Amomum villosum Lour. as Chinese herbal medicine and seasoning, which has a huge potential economic value. This plant is increasing shortage of resources by the slow sexual reproduction and the low artificial reproduction rate. The plants with strong stress resistance and high yield were selected as the female parent, on the basis of single factor and complete combination, the orthogonal test of L9 (34) and L16 (45) was further conducted. 6-BA induced basal stem cluster bud formation was obviously better than that of KT or ZT. 2, 4-D significantly induced callus occurrence and node enlargement, while NAA was more beneficial to adventitious root formation The combination of 6-BA and NAA was more beneficial to induce the formation of cluster buds from basal stem, but the proliferation effect was not ideal. Thus, KT or 2, 4-D was introduced for two orthogonal tests of L9 (34), and the highest proliferation coefficient was only 4.56. Then it was found that adding 0.5 mg·L-1 2, 4-D to the above combination, appeared a unique phenomenon of node propagation. Next, L16 (45) orthogonal test was conducted using 4 plant growth regulators combinations of 6-BA, 2, 4-D, KT and NAA. The optimal medium for proliferation culture was the MS medium with 7.5 mg·L-1 6-BA, 5.0 mg·L-1 NAA, 1.5 mg·L-1 KT, 0.5 mg·L-1 2, 4-D, and the proliferation coefficient reached above 10.00. The optimal rooting medium was the 1/2 MS medium with 2.0 mg·L-1 NAA. With the node propagation, a rapid propagation system of A. villosum was established which provided a possible solution for improve the efficiency of artificial planting, solve the market demand and quality problems.

Kajian Kesesuaian Lahan Tanaman Padi Sawah di Kecamatan Tanjung Selor Berbasis Sistem Informasi Geografis

Evaluation of the level of land suitability for rice crops is used in planning agricultural land use so that inhibiting factors and solutions can be found in processing land to be planted. This study aims to evaluate the suitability of land for rice crop plants by implementing a geographic information system that facilitates and accelerates the data processing process so that research output can be used for consideration in land use in Tanjung Selor Subdistrict of Bulungan District. The variable used in this study was temperature, water availability (rainfall), oxygen availability (soil drainage conditions), root media (soil texture), erosion hazard (slope), flood hazard (inundation), and land use. Rainfall data are obtained from the analysis of climate factor data from 2011 to 2020, soil texture data is obtained from field observations and soil maps, slope data were obtained from the Digital Elevation Model in 2014, and land use data is obtained from land-use map interpretation in 2019. Of the seven parameters, four parameters are obtained from the map, namely rainfall map, soil map, slope map, and land use map. Soil sampling and observations in the field in 2021 are carried out to obtain data on temperature, flood hazards, and soil drainage conditions. Based on the results of the analysis of land suitability of rice in Tanjung Selor Subdistrict, 13,65% is suitable marginal, and 86,35% is not suitable for planting rice. Tanjung Selor Subdistrict is dominated by areas that cannot be planted on and can be planted, but the results are less than optimal.

Organogenesis from Leaf-derived Calli of S. potatorum L. f.: A Vulnerable Medicinal Tree Species

An efficient protocol for in vitro regeneration of Strychnos potatorum L. f. through indirect organogenesis was developed using mature leaf disc explants. The explants were selected from twenty years old tree. Cultured on Murashige and Skoog’s medium supplemented with 2,4-dichloro phenoxy acetic acid (2,4-D) was used for the induction of organogenic calli. A pale yellow coloured friable callus developed at 2 mg/L-1 2,4-D where showed higher morphogenic potential. Further de-novo shoots formation and multiplication in optimal concentrations of cytokinins with different combinations of auxins. An average mean shoots number (14.2±0.42) and shoots height (3.5±0.27cm) was obtained from piece of calli in 6-benzylaminopurine (BAP) 1 mg/L-1 with 0.5 mg/L-1 α-naphthalene acetic acid (NAA). BAP in combinations with NAA was found to be superior to shoot development than other combination used. The well developed shoots were transferred to root induction medium for effective rooting. The rooting medium consisted of in half-strength MS medium augmented with 0.5 mg/L-1 NAA was used. The maximal mean number of roots per shoots 6.5±0.53 was recorded in 4 weeks. The rooted plantlets were removed from the culture tubes, gently washed with sterile double distilled water to remove agar adhering on the plant surface. The regenerated plants were transferred to plastic cups filled with a potting mixture containing sterile sand and soilrite (1:1 ratio) and allowed to grow in the greenhouse. The slowly acclimatized plants were further transferred to substrate containing red soil and farmyard manure (1:1) for effective hardening. 75% survival rate was recorded. This protocol can be useful for the ex-situ conservation and rehabilitation of this vulnerable medicinal tree S. potatorum.
 Keywords: Indirect organogenesis, friable callus, shoot development, 6-benzylaminopurine, α-naphthalene acetic acid

Improving galegine production in transformed hairy roots of Galega officinalis L. via elicitation

Galega officinalis L. is an herbaceous legume used to treat symptoms associated with hyperglycemia or diabetes mellitus because of its dominant alkaloid, galegine. In this study, we induced hairy roots in this plant using Rhizobium rhizogenes strain A4, and investigated the effect of type, concentration, and duration of elicitor application on galegine content and some phytochemical characteristics in the hairy roots. Hence, the best growing hairy root line in terms of growth rate was selected and subcultured for treatment with elicitors. Then, at the end of the log phase of growth, chitosan (100, 200, and 400 mg/L), salicylic acid (100, 200, and 300 mM), and ultrasound (1, 2, and 4 min) were applied to hairy roots culture medium. High-performance liquid chromatography (HPLC) showed that the content of galegine was significantly increased after elicitation compared with the control. Thus, the highest content of galegine (14.55 mg/g FW) was obtained 2 days after elicitation when ultrasonic waves were applied to the hairy root culture medium for 4 min. Also, elicitation resulted in a significant increase in the content of total phenol, flavonoid, H2O2 and MDA compared with the control. So that the highest total flavonoid content was obtained in hairy roots that were treated with ultrasonic waves for 4 min and harvested 2 days after elicitation; while, application of 400 mg/L chitosan for 4 days resulted in the highest total phenol (16.84 mg/g FW).Graphical

​Effect of Plant Growth Regulators on Rooting of Avocado (Persea americana Mill.) Cuttings in Sikkim

Background: Avocado (Persea americana Mill.) family, Lauraceae, sub-tropical evergreen tree, which is very nutritious fruit having large oil fraction which is one of the unique features and has good medicinal properties. The vegetative propagation of avocado has become increasingly important to produce a large amount of planting material. Methods: The present study was conducted in the research field at the Department of Horticulture, Sikkim University, Gangtok during 2016-2017 to evaluate the effect of different concentration plant growth regulators on the rooting of two cultivars. Hass and Fuerte Avocado (Persea americana Mill.) cuttings were investigated at the mist chamber. The experiment was laid in a completely randomized design for avocado cuttings of cvs. Hass and Fuerte with eighteen treatments comprising of different concentrations of IBA (control, 200 ppm, 400 ppm, 800 ppm, 1000 ppm) and NAA (control, 200 ppm, 400 ppm, 800 ppm, 1000 ppm). In all the treatments the cuttings were dipped in the plant growth regulators for 10 seconds. Rooting medium for planting the avocado cutting used was fine coarse vermiculite 80%, soil 10% and well rotten cow dung manure 10% in the ratio of 8:1:1 respectively for all the treatments. Result: In general, the results showed a significant increase for root initiation under treatment (IBA 800 ppm + Fuerte) followed by (IBA 400 ppm + Fuerte) which took 105.67 days for root initiation as compared to control at 5% level of significance. The avocado cuttings exhibited significant results for root initiation was 99.33 days which was recorded under treatment IBA 800 ppm + Fuerte as compared to treatment Fuerte (control) which was 121 days observed in root initiation. The maximum number of 14.05 roots at the time of transplanting in cuttings under treatment IBA 400 ppm + Fuerte and minimum was 2.00, 2.11, 2.22, 2.66 and 2.89 observed in treatment control + Hass, NAA 200 ppm + Hass, IBA 1000 ppm + Hass, IBA 200 ppm + Hass and IBA 400 ppm + Hass respectively. The maximum length of 1.53 cm root at the time of transplanting was found with treatment IBA 400 ppm + Fuerte and the minimum was 0.17 cm observed in treatment Hass (control). The rooting 72.22 percentage at the time of transplanting in cuttings was observed treatment IBA 400 ppm + Fuerte and minimum was 11.11 percentage observed in Hass (control). Fuerte with IBA 400 ppm was better in rooting capacity as compared to others.

Adventitious Root Culture—An Alternative Strategy for Secondary Metabolite Production: A Review

Medicinal plants are valuable sources of botanical drugs, extracts and pure compounds. Although several species can be propagated or collected, the access to herbal material is limited in certain cases. The protection of natural habitats and biodiversity demands new sources to provide plant secondary metabolites of medical importance. Adventitious root culture is used to harvest the secondary metabolites from the medicinally important plants, thereby offering an alternative to collection and propagation of medicinal plants. In this review, we comprehensively summarize the previously published data on the use of adventitious root cultures for numerous therapeutic plants. Adventitious roots showed elevated growth rates and production of pharmaceutically important metabolites under sterilized condition with optimized plant-growth regulators in culture media. In the present study, major influencing factors, such as the stages involved in the process of adventitious root formation, medium composition and type of growth regulators, specifically the effect of different auxins on the initiation and formation of roots, are discussed. Elicitation strategies using biotic (yeast extracts, chitosan and pectin) and abiotic factors (MJ, SA, CuSO4, AgNO3, NaCl) that affect the in vitro growth of adventitious roots and the role of bioreactors, which are new advancements in the scale-up process, are also highlighted. The development of adventitious root cultures for the production of secondary metabolites of medicinal importance is a perspective that is advantageous from ecological and economical aspects as well.

Analysis of limiting factors for food agriculture development in peatland areas

This study aims to determine the main limiting factors in agricultural development on peat lands and the agricultural input to improve it. The study was conducted in peat land of the Sriwijaya Botanical Gardens, Bakung Ogan Ilir Village, South Sumatra, Indonesia. A detailed survey was designed based on a map scaling of 1: 5,000 and analyses of peat samples were carried out in the Soil Science Department Laboratory of Sriwijaya University. The Soil Map Unit (SMU) was then generated based on peat depth and its maturity. The indicator of agricultural food crops is corn. The results showed that the maturity of the peat was dominated by sapric, the depth was divided into two classes, namely 1.5-2m and >2m. The actual land suitability of the site was unsuitable (Nrc, nr) with the limiting factors, i.e. nutrient retention and root media. The limitation of nutrient retention was on low soil pH and low potassium. Whereas, Nitrogen and Phosphorus content were considered as high and medium. By giving agricultural input, the potential land suitability class improve to S3rc (less suitable) with the limiting factor including peat depth. There were some areas considered as permanently unsuitable (Nrc) due to peat depth. Drainage control is essential management to ensure crop water availability.

Establishment and Optimization of Plant Growth Media for the Propagation of Mas Cotek (Ficus deltoidea Jack var. trengganuensis)

The propagation of Mas Cotek using tissue culture techniques is time-consuming and requires specific conditions. Therefore, this study was conducted to determine the best rooting media formulation to propagate Mas Cotek under field conditions. First, the effects of plant growth media (rice husk biochar (RHB), bris soil, cocopeat (CC), peatmoss, and a mixture of 3CC: 7RHB) on plant traits were investigated. Subsequently, the optimal ratio of CC and RHB for Mas Cotek propagation was carried out. In addition, the evaluation of the traits of the Mas Cotek plant when grown with the mixture of 3CC: 7RHB enriched with different rooting-promoting materials (effective microorganism, Agromedia™, Indole-3-butyric acid (IBA), organic fertilizer, peatmoss, and seasol) was also performed. Plant growth variables measured were the total number of roots, length, plant biomass, chlorophyll content, and stem diameter. Planting media characters observed were soil pH, soil electrical conductivity, and plant growth media biomass. The results showed that Mas Cotek propagated best in the combination of 3CC:7RHB growth media added with IBA. This plant growth media has enhanced the total root, root length, plant biomass, root biomass, stem diameter and chlorophyll content of the plant seedlings. The pH of plant growth media (7.00-neutral) and electrical conductivity (0.61 mS/m) are also suitable for growing many types of plants. Findings will help farmers choose the best plant growth media to propagate their plant seedlings.
 Keywords: Mas Cotek, Ficus Deltoidea, Plant Growth Media, Plant Propagation, Rooting

Induction of adventitious buds and establishment of an efficient regeneration system in Polygonatum cyrtonema Hua

Polygonatum cyrtonema Hua is not only a widely used traditional Chinese medicine, but also processed into food and cosmetics. However, its large-scale cultivation and application are limited by the low reproduction rate for traditional artificial propagation technology. Therefore, the aim of this study was to establish an efficient and stable adventitious buds induction system for P. cyrtonema by using one bud rhizome segment as initial explants. The results showed that the optimal medium for the rhizome growth, adventitious buds occurrence and proliferation was MS medium supplemented with 3.0 mg·L–1 BA, 1.0 mg·L–1 NAA and 1.0 mg·L–1 KT, with a proliferation coefficient of 6.5. The best rooting medium was found to be half strength of MS medium with 0.5–1.0 mg·L–1 NAA. The survival rate was higher than 95%. Finally, an asexual rapid propagation system of P. cyrtonema was established, which can provide the technical basis for the development of nursery culture.

Rooting and growth characteristics of ‘Maehyang’ strawberry cutting transplants affected by different growing media including decomposed granite

This study was conducted to examine the effects of different rooting media that include decomposed granite on the rooting characteristics and growth of strawberry cutting transplants. The six rooting media that were used in the experiment included coir (CO), mixed media (MIX, coir:perlite = 8:2, v/v), perlite (PL), decomposed granite 1–3 mm (GS), decomposed granite 3–5 mm (GM), and decomposed granite 5–9 mm (GL). The cuttings of strawberries were transplanted on January 4, 2021. Humidification was carried out for 14 days. At 14 days after cutting, a rooting rate of 100% was confirmed in all media. However, cutting transplants in GM and GL, which were quite large in particle size, showed a low likelihood of survival. At 28 days after cutting, the fresh weights of shoot and root were significantly higher in CO, as compared to the others, but the dry weights showed no significant differences regardless of the growing media. The root growth of strawberry cutting transplants showed the highest values in GS at 14 days after cutting (and end of humidification). However, at 28 days after cutting, the transplants in the CO medium showed better root growth than those in the other media. Chlorophyll fluorescence values (Fv/Fm) were decreased at 28 days after cutting in the GM and GL media. In conclusion, we found that GS has potential for use as a strawberry rooting medium.

Alleviation of drought stress by root-applied thiourea is related to elevated photosynthetic pigments, osmoprotectants, antioxidant enzymes, and tubers yield and suppressed oxidative stress in potatoes cultivars.

The growth and productivity of plants are enhanced by the use of thiourea (TU) under stressful conditions. When TU is applied as a rooting medium, it improves plant growth characteristics and other physiological parameters in stressed environment. A pot experiment was conducted in the botanical garden of the Government College University, Faisalabad 38000, Pakistan to examine the TU-mediated fluctuations in some crucial physio-biochemical parameters and the oxidative defense of potatoes under a restricted water supply. For this purpose, two potato cultivars (potato-SH-5 and potato-FD-73) were sown in pots containing 10 kg of soil. Water was regularly applied to the pots until germination. After 2 weeks of germination, drought stress with 65% field capacity was imposed, while the control was subjected to 100% field capacity. TU, as a rooting medium, was applied at the vegetative stage (0 (no application), 0.5, 0.75 mM). A substantial reduction in the total number of leaves, leaf area, tuber biomass (fresh and dry weight), photosynthetic pigments, membrane permeability, and leaf relative water content (RWC) was recorded in plants under drought stress conditions as compared to control plants. The damaging effects of water stress were more critical for cv. potato-FD-73 as compared to cv. potato-SH-5. In contrast, drought stress enhanced the malondialdehyde (MDA) and hydrogen peroxide (H2O2) content while also increased antioxidant enzyme activities (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)) and triggered the accumulation of soluble proteins, soluble sugars, proline, and phenolic and anthocyanin contents. However, TU applied as rooting medium at 0.5 and 0.75 mM was effective in reducing the detrimental effects of water stress in both cultivars. Furthermore, increasing levels of TU enhanced chlorophyll pigments, dissolved proteins, complete dissolved sugars, and enzymatic capabilities of POD, SOD, and CAT, while reducing the MDA and H2O2 in both cultivars under stress conditions. In conclusion, TU improved the yield and chlorophyll pigments of potato plants by mitigating the adverse effects of drought stress through reduced EL, MDA, and H2O2 contents and improved activities of enzymatic and non-enzymatic antioxidants and osmoprotectants.

Effects of Iron Deficiency Stress on Plant Growth and Quality in Flowering Chinese Cabbage and Its Adaptive Response

Iron (Fe) plays an important role in the growth and development of plants. The effects of different Fe concentrations, 1-aminocyclopropane-1-carboxylic acid (ACC), and cobalt chloride (Co2+) treatments on plant growth, quality and the adaptive response to Fe deficiency stress were investigated in flowering Chinese cabbage. The results revealed that Fe deficiency stress inhibited plant growth. The contents of vitamin C, soluble protein, and soluble sugar in leaves and stalks were significantly reduced under Fe deficiency stress, while the content of cellulose and nitrate was increased. Fe deficiency stress clearly reduced the net photosynthetic rate and nitrate reductase activity in the leaves. The balance system of active oxygen metabolism was destroyed due to Fe deficiency, resulting in the decrease in catalase activity, superoxide dismutase activity of roots and leaves, and peroxidase (POD) activity of leaves, while POD activity in roots and malonaldehyde content in roots and leaves were significantly increased. The treatments of Fe deficiency and ACC significantly reduced the pH value of the root medium, promoted the release of ethylene, and increased Fe3+ reductase activity, while Co2+ treatment showed results that were the opposite to those of Fe deficiency and ACC treatments. Thus, Fe deficiency stress affected nitrogen metabolism, photosynthesis, reactive oxygen metabolism, pH of root medium, and Fe3+ reductase activity, which was related to physiological adaptive response and tolerance mechanisms. We also found that ethylene could be involved in regulating the adaptive response to Fe deficiency stress in flowering Chinese cabbage.

Standardization of media and container for improving seed and seedling growth in papaya (Carica papaya) cv. Red Lady

An experiment was conducted to standardize the suitable media and type of the container for improving seed germination and seedling growth of papaya (Carica papaya L.) cv. Red Lady during 2019–20. Five different types of media and three types of containers were used for study. Present experiment was conducted in a Complete Randomized Block Design (Factorial) with 15 treatment combinations replicated thrice. The observations were recorded on seed germination attributes and seedling growth parameters. The results showed that the plastic containers were found better followed by earthen pots and polybags using media mixture of soil + cocopeat + vermicompost (1:1:1) for improving seed germination (94.76%). However, the maximum plant height (17.40 cm), number of leaves (12.03), stem girth (6.42 mm), leaf area (131.02 cm2), root length (18.60 cm) and seedling survival (97.30%) was observed in the earthen pots having rooting media mixture made up of garden soil + cocopeat + vermicompost + FYM (1:1:1:1). The seed germination and plant growth parameters, root length and seedling survival was recorded in polybags.

Efficient plant regeneration system for New Guinea Impatiens (Impatiens hawkeri W. Bull) CV. ‘Violet’ and ‘Scarlet Bronze Leaf’

New Guinea Impatiens (Impatiens hawkeri W. Bull) is an eye-popping landscaping plant of bright and colorful blooms. A highly efficient in vitro plant regeneration system via direct shoot organogenesis was established for the first time from hypocotyl with partial cotyledons of New Guinea Impatiens. Our results showed that the explant sterilization method, basic medium type, AgNO3, sucrose and plant growth regulators have significantly influenced in vitro morphogenesis. The regeneration rate in regeneration media that MS supplemented with 0.5 mg·L−1TDZ and 0.1 mg·L−1NAA was acceptable, the induction rate of ‘Violet’ was 86.67%, and its proliferation coefficient was 5.27, while the induction rate of 'Scarlet Bronze Leaf' was 83.33%, and its proliferation coefficient 5.13. PIC could not induce clumped sprouts; however, it had a better effect on callus induction. We also included a shoot multiplication stage using regeneration New Guinea Impatiens medium that MS supplemented with 0.8 mg·L−16-BA, 0.5 mg·L−1TDZ and 0.05 mg·L−1NAA. Reducing sucrose concentration to 20 g·L−1 or adding 1 mg·L−1AgNO3 could alleviate the hyperhydricity phenomenon in the process of tufted bud proliferation. The optimal root culture medium for the regenerated seedlings of ‘Violet’ and 'scarlet bronze leaf' of New Guinea Impatiens was MS supplemented with 0.05 mg·L−1IBA, the rooting rate reached 100%.The study examined the micropropagation responses of New Guinea Impatiens in the presence of various growth regulators, which provide a simple and more suitable protocol adapted for the mass propagation of clones.

ISOLATION, CLONING AND AGROBACTERIUM MEDIATED TRANSFORMATION OF MYMV REPLICASE (REP) GENE IN VIGNA RADIATA (L.) WILCZEK FOR MYMV RESISTANCE

The binary plant cloning vector pCAMBIA1305.2 carrying the MYMV Replicase (Rep) gene was constructed and transformed into a competent Agrobacterium tumefaciens, strain LBA4404 and was used for co-cultivation of mungbean varieties, KKM-3, IC-39340-1, China mung and LM-1668 for imparting mungbean yellow mosaic virus (MYMV) resistance. The putative transformants (To generation) were selected on shooting media (SM) supplemented with 5 mgl-1 BAP, 50 mgl-1 hygromycin and 250 mgl-1 cefotaxime. The multiple shoots were inoculated on shoot elongation media (SEM) with 0.3 mgl-1 zeatin and 2.5 mgl-1 BAP for elongation and rooted on rooting media (RM), comprising half MS supplemented with 0.2 mgl-1 NAA. The GUS assay and genomic PCR analysis of the To transformants revealed, four positive putative transgenic lines for Rep gene specific primers and had a positive correlation with vector specific hptII primers. Likewise, VirG amplification revealed no Agrobacterium contamination in the apoplast of allthe putative To transformants.

First Report of Root Rot Caused by Pythium dissotocum on Hydroponically Grown Collard Greens (Brassica oleracea var. acephala).

Collards (Brassica oleracea var. acephala) are grown throughout the United States. Hydroponic greens are more common now due to technological advances lowering the cost and increasing the efficacy of production. In January 2021, a 325 m2 indoor hydroponic farm opened to provide fresh produce for a school in Los Angeles County, CA. Three week old collard seedlings were purchased from a local nursery, rinsed of their rooting media, and transplanted into deep water culture beds (1.2 m x 2.5 m x 0.3 m). Two weeks later, symptoms including plant stunting, chlorosis, leaf curling and wilting, and brown necrotic roots appeared. By and by 80-100% of usable plants were lost to disease. Symptomatic roots were plated on corn meal agar (CMA) amended with 2 ml of 25% lactic acid and CMA amended with pimaricin, ampicillin, rifampicin, and pentachloronitrobenzene (PARP) (Kannwischer et al. 1978). After 2 days a single colony type emerged on PARP but no growth occurred on acidified CMA. Representative isolates were transferred to CMA and to filtered (0.02 µm) soil extract solution with boiled grass blades (Martin 1992), both of which were incubated at 22 C and ambient light conditions. On CMA, isolates produced coenocytic mycelium with minimal aerial hyphae. After 24 h in soil extract, isolates developed filamentous sporangia, elongated discharge tubes with slightly inflated tips, and zoospores. Oospores were not observed. Pathogenicity was confirmed by soaking the roots of five day old collard seedlings in beakers containing zoospores (1 x 102 zoospores/ml) in filtered soil extract. Four isolates were tested on 15 seedlings each. After 24 h at 22 C in ambient light conditions, plants were transferred to new beakers with roots placed on filter paper at the bottom and saturated with sterile distilled water. Three days after this transfer, leaves on all plants turned chlorotic and roots developed brown lesions from which morphologically identical colonies were isolated. Control plants, soaked in filtered soil extract, developed no root or foliar symptoms. To molecularly identify the collard isolates, DNA was extracted from mycelial original and re-isolated isolates and was amplified by PCR using mitochondrial primers for the cytochrome oxidase I (COI) gene (Robideau et al. 2011) and the cytochrome oxidase II (COX2) gene (Martin 2000). The only species that matched both loci from the original and re-isolated isolates with a high percent identity was Pythium dissotocum. The COI locus from the original isolate (MZ027311) matched P. dissotocum with 99% identity and with 332/334 base pairs matching the isolate with Sequence ID MT981134.1. From the re-isolated isolate (MZ027313), the COIequence perfectly matched 657/657 base pairs of P. dissotocum (Sequence ID MT981147.1). The COX2 locus from the original isolate (MZ027312) matched P. dissotocum (Sequence ID MG719859.1) with a 99% identity and 517/518 matching base pairs and the re-isolated isolate (MZ027314) perfectly matched P. dissotocum (Sequence ID MG719859.1) with 515/515 matching base pairs. Based on these molecular and morphological data, the isolates were identified as Pythium dissotocum. To our knowledge, this is the first report of P. dissotocum causing root rot on collards. At this same facility, P. dissotocum was also confirmed as the cause of declining bean (Phaseolus vulgaris) plants. As hydroponics will be necessary to feed a growing population - especially in urban areas -- and because leafy greens are a main crop of the hydroponics industry, we anticipate this issue may become common. Hydroponic systems are highly conducive to the persistence of Oomycetes and a record of infection and plan of action will be necessary to preserve crop health.

Baccor, in vitro formation of biofilm in broken endodontic files in radicular canals

The aim of this study to evaluate the biofilm formation of sulfate-reducing bacteria from two microbial species, Desulfovibrio desulfuricans (oral and environmental strain) and Desulfovibrio fairfieldensis, in root canals with fractured endodontic files in vitro and the biocorrosive changes that these strains are capable of promoting on the metal surface of endodontic files. Fourteen teeth were included with fractured # 90 Kerr files and inoculants of Desulfovibrio desulfuricans strains and Desulfovibrio fairfieldensis in a modified Postgate E culture medium. The inoculated teeth were evaluated at 28, 41, 51 and 477 days. The biofilm was evaluated through scanning electron microscopy (SEM) and confocal laser scanning microscope with the fluorophore the Live / Dead® kit. For the 477 day, chemical pickling followed, with subsequent evaluation of the metallic surface of endodontic files in the SEM. In the biofilm analyzes of 28, 51 and 477 days, a mixed biofilm was observed, with a predominance of living cells and areas of corrosion along the entire metallic surface of the file for the last time, contrasting the metallic surface of the control groups. The SRB showed cellular activity both on the metal surface of the file and on the dentin surface of the root canal at the deepest levels of the root canal, apical and medium, promoting biocorrosion along the metal surface of endodontic files.

In vitro Regeneration of Japanese Burdock (Arctium lappa L.) from Cotyledon and Leaf Derived Explants

Considering the vegetable and medicinal values, a micropropagation protocol has been established for Japanese Burdock (Arctium lappa L.) by culturing the explants of cotyledon and leaf obtained from in vitro grown seedlings. Direct shoot regeneration was achieved from cotyledon and leaf explants on MS fortified with 4.0 μM BAP and 2.0 μM IBA or NAA after 5 weeks of culture. In addition, both the explants also formed callus from their cut margins within 6 weeks of cultivation on medium complemented with 6.0 μM BAP and 4.0 μM IBA or NAA. Adventitious shoots were also redeveloped through indirect organogenesis from the cotyledon and leaf-derived callus within 10 weeks of culture on MS containing 4.0 μM BAP and 2.0 μM IBA or NAA. The highest rate of shoot reproduction was attained at the third subculture, and more than 12.6 shoots were formed per callus clump. Within 4 weeks of transfer to the rooting medium on MS containing 6.0 μM IBA, the cultured micro-shoots produced highest 5.3 roots per cultured shoot. Rooted plantlets were successfully established on a soil-composed-sand mixture under natural condition with 93.3% survival rate Plant Tissue Cult. & Biotech. 31(2): 123-134, 2021 (December)

Effect of different growing media for elite seedlings production in Arabica coffee (Coffea arabica L.)

Study on identifying the suitability of different growing media for seedling establishment and elite seedling production in Arabica coffee (Coffea arabica L.) cv. Chandragiri was conducted with an objective to evaluate the suitability of different growing media for raising the seedlings and to find out most suitable media for better rooting and growth of coffee seedlings. Coffee seedlings were grown in different media for a period of 6 months in nursery. It was revealed from the study that, the growth and vigour of coffee seedling was greatly influenced by different growing media used. Coffee seedlings grown in growing media containing Soil + Sand + Vermicompost (6:2:1) recorded maximum germination (64%), seedling vigour (2125), seedling height (51.7 cm), number of leaves (8.3), leaf area index (71.17 cm2), diameter of stem (2.18 cm), seedling fresh weight (16.79 g) and higher seedling dry weight (3.09 g) when compared with control and other treatments.

EFFECT OF SALT STRESS ON RICE SEED GERMINATION AND SEEDING GROWTH

PURPOSE: the purpose of the study was to analyse the influence of different NaCl concentrations on germination and seedling parameters in three rice cultivars belong to species Oriza sativa L. - Osmanchik 97, Kameo and Luna. METHODS: six NaCl salt concentrations were studied (low concentrations: 25 mM and 50 mM NaCl solutions, medium concentrations: 75 mM and 100 mM NaCl solutions and high concentrations: 125 mM and 150 mM NaCl solutions). Germination data and seedling parameters were recorded. RESULTS: The application of salt concentrations between 25 and 150 had no significant effect on seed germination, while suppressive effect on seedling characteristics. At 150 mM NaCl mean germination time ranged from 2.10 days (for Osmanchik 97) to 3.15 days (for Kameo), mean ShL ranged from 3.65 cm for Kameo to 5.33 cm for Osmanchik 97. With increasing concentrations of NaCl vigor index decreased from 2043 for Osmanchik 97 (control) to 1050.24 for the variety Kameo. CONCLUSION: At 150 mM NaCl concentrations, the studied varieties showed very high salt tolerance to seed germination, high salt tolerance to root growth and medium salt tolerance to shoot growth. Тhe study confirmed that rice cultivars at the stage of seed germination are more tolerant to salinity than at the early seedling stage.