Acclimatization Of Plantlets Research Articles

Assessment of genetic uniformity in micro propagated plantlets of turmeric (Curcuma longa L.) through DNA markers

Turmeric is herbaceous plant, characterized by long lance-shaped leaves sprouting from its rhizomatous underground stem. Notably, its rhizomes contain the bioactive compounds curcuminoids, renowned for its medicinal and culinary significance. However, meeting the surging demand for turmeric, particularly during off- seasons, presents a formidable challenge due to the sluggish vegetative propagation rate in Curcuma longa. Given the scarcity of sexual reproduction in turmeric, micropropagation emerges as the convenient method for obtaining disease-free seeds. In addressing the challenge of direct regeneration of the native Erode local cultivar of turmeric, this study endeavors to establish a protocol for in vitro plantlet production. Results indicate that multiple shoots were successfully induced, notably with 13.32 μM of 6-benzylaminopurine (BAP), yielding a response rate of 73.2±4.7% and an average shoot count of 6.95±0.81 per explant. Subsequently, a concentration of 17.76 μM of BAP demonstrated a response rate of 56.5%±4.7%, with an average shoot count of 5.94±0.81 per explant. Additionally, a combination of 13.32 μM BAP and 2.68 μM Naphthaleneacetic acid (NAA) resulted in 8.65±0.47 shoots per explant, with a response rate of 73.66±1.25%. Similarly, 13.32 μM BAP combined with 5.37 μM NAA yielded 7.32±0.47 shoots per explant, with a response rate of 72.33±0.47%. The acclimatization of plantlets in a greenhouse exhibited a remarkable survival rate, ranging from 90% to 98%. Importantly, all regenerated plantlets closely resembled the mother plants morphologically. Genetic uniformity assessment, employing 10 ISSR and 4 DAMD markers, indicated more than 90% uniformity among one mother plant and regenerants. This indicates a significant genetic uniformity, ensuring consistency in desired traits across the regenerated plantlets.

Influence of growth regulators on microclonal propagation of <em>Scrophularia umbrosa</em> Dumort under <em>in vitro</em> conditions

The possibility of effective microclonal propagation of Scrophularia umbrosa Dumort for producing planting materials, aimed at preservation of the species has been shown. This will aid in the creation of artificial introduction populations of this endangered species in the Republic of Tatarstan, Russia. Optimal conditions for surface sterilization of seeds, development of microshoots, in vitro rooting and acclimatization have been developed. The most effective surface sterilization and germination was achieved with 10 % commercial bleach. Nodal explants were cultured in Murashige and Skoog’s (MS) medium with different concentrations of 6-benzylaminopurine (BAP) and indole-3-acetic acid (IAA). The maximum number of microshoots was developed on MS medium containing 1.0 mg/l of BAP and 1.0 mg/l of IAA. Full strength MS medium with only IAA or together with (indole-3-butyric acid) IBA is optimal for rapid rooting of microshoots. The combination of soil: perlite (2:1) (v/v) was the best for ex vitro acclimatization of plantlets.

Growth of Black Orchids (Coelogyne Pandurata Lindl) with Additional Ecoenzyme Liquid Organic Fertilizer and Biostimulant of Cengkodok Leaf Extract

Acclimatization of black orchid plantlets (Coleogyne pandurata Lindl.) with cengkodok leaf extract biostimulant treatment has been successfully carried out, but still have slow growth. To support growth and development at the enlargement stage, cultivated orchids need to be given eco enzyme liquid organic fertilizer (LOF) derived from various sources of organic matter. Provision of ecoenzyme LOF combined with biostimulant 20 mg/l of Cengkodok leaf extract to increase the efficiency of nutrient absorption. The aim of the research was to find the best type and concentration of LOF for the growth of black orchids at the enlargement stage. The study used a Complete Randomized Design (CRD) with two treatment factors namely type of LOF (ecoenzyme (ee) LOF from vegetable and fruit waste, ee LOF from pineapple peel waste, and "NASA" LOF) and . the POC concentration (0; 0.5; 1.0; and 1.5 ml/l). The results showed that the single treatment of ee LOF significantly effected the number of leaves and the number of black orchid tillers, while the single treatment of ee LOF concentration had an effect on the parameters of height, number of leaves, number of tillers and leaf area of black orchid. The parameter of chlorophyll content had no signifcant effect by the type and concentration of LOF. The largest leaf area was shown in the addition of ee LOF from vegetable and fruit waste at a concentration of 1 ml/l which was 11.88 cm2.

Application Of Pes Fertilizer To The Growth Of Kappaphycus alvarezii Plantlets

This study aims to determine the growth of Kappaphycus alvarezii plantlets applied with different PES fertilizers. This research was conducted at Blitok Installation, brackish water aquaculture center, Situbondo. This study began with the preparation of water as a maintenance medium, acclimatization of plantlets in the greenhouse, maintenance of plantlets in the greenhouse (plantlet cleaning, fertilization), and checking water quality. The application dose of PES fertilizer given as treatment was 15 ml, 20 ml, and 25 ml which was repeated 3 times. The rearing design used a completely randomized design (CRD) model. The results obtained showed that the average absolute weight gain of planlets from the 15 ml treatment was 0.249 g - 0.271 g, the 20 ml treatment was 0.35 g - 0.432 g, and the 25 ml treatment ranged from 0.306 g - 0.372 g. For the specific growth rate from the first to the fifth week of rearing, the 15 ml treatment ranged from 3.162-1.693, the 20 ml treatment ranged from 3.922-4.21 and the 25 ml treatment ranged from 2.899-3.904. From the results of the study, it can be concluded that the application of a PES fertilizer dosage of 20 ml gave better growth than the 15 ml and 25 ml doses. Keywords: growth, Kappaphycus alvarezii, plantlets, PES fertilizer, dosage

In Vitro Propagation of Two Tomato Hybrids (Lycopersicon Esculentum Mill.) Via Tissue Culture Technique

This investigation was carried out at the Tissue Culture Lab., Biotechnology Research Center (BTRC) in Tripoli, Libya in 2009 to establish a micro propagation protocol for two hybrids of Tomato in which several factors were studied including the effect of concentration of growth regulator on shoot multiplication, and rooting of explant on MS media. Shoot tips were cultured into (MS medium) with different concentrations of benzyl adenine (BA) + 0.5 mg/l (IAA) compared with MS basal medium as a control treatment. Generally, the results showed that there were no significant differences between several concentrations of (BA+IAA) on the number of leaves and shoot length. The obtained results illustrated was M1 gave high number of shoots/explant, shoot length, and leaves number for two hybrids of Tomato which were 1.90, 3.89, 4.48 respectively compared with the control. The results showed that there were no significant differences between Tomato hybrids on shoot length and the number of shoots. The best result for leaves number was hybrid HH-56 which gave 4.54 leaves. From the foregoing results, MS media supplementing IAA at 0.2 mg/l was the best treatment for rooting stage of hybrid HH-56 and Hybrid AZHAR F1. The plantlets were transferred to plastic cups containing peatmoss + sand at 1:1 (V/V). Acclimatization of plantlets were successfully.

In Vitro Propagation of Philodendron erubescens ‘Pink Princess’ and Ex Vitro Acclimatization of the Plantlets

This study describes the in vitro propagation and ex vitro acclimatization of Philodendron erubescens pink princess, one of the most popular ornamental variegated foliage plants. For shoot proliferation, the protocorm-like bodies of the Philodendron pink princess were cultured on solid Murashige and Skoog (MS) media supplemented with 6-benzylaminopurine (BAP) and 1-naphthaleneacetic acid (NAA) at different concentrations. The results revealed that supplementation with BAP alone at a concentration of 1.0 mg/L yielded the maximum number of shoots and leaves. Furthermore, the application of BAP at 1.0 mg/L significantly enhanced the shoot proliferation of Philodendron pink princess when grown in liquid MS medium, yielding 11.2 shoots/explant and 4.7 leaves/explant. When the established microshoots were subjected to root induction using solid MS media supplemented with different kinds and concentrations of auxins, indole-3-butyric acid (IBA) at 3 mg/L resulted in the highest number of roots (3.2 roots/explant) and longest root length (1.9 cm). Three supporting materials, i.e., peat moss, vermiculite, and perlite, were used as planting media for the ex vitro acclimatization of the Philodendron pink princess plantlets. The results demonstrated that the in vitro plantlets acclimatized and exhibited a relatively high survival frequency in all planting media without morphological abnormalities. Peat moss outperformed all other types of planting media in terms of sustaining the vegetative growth of the plantlets. In the future, the approach established in this study could be employed for the extensive production of Philodendron pink princess.

Tissue culture of gerunggang (Cratoxylum arborescens (Vahl) Blume): multipurpose native species of Indonesian peatland

Gerunggang (Cratoxylum arborescens (Vahl) Blume) is a tree native to Indonesian peatlands that has great potential as an alternative fiber-producing species for the pulp and paper industry because it is adaptable and does not have the potential to disrupt local ecosystems. The species also contains important anti-cancer compounds for the pharmaceutical industry. These industries require large quantities of raw materials to meet their needs, which cannot be met by the supply of conventional plant seedlings. Tissue culture is one of the propagation biotechnologies that can be used as an alternative to provide more efficient germplasm. In this study, we developed a protocol for gerunggang propagation using tissue culture technique. The results showed that the combination of 1 mg/l 6-benzylamino purine (BAP) and 0.5 mg/l naphthalene acetic acid (NAA) in Murashige & Skoog media provided the fastest bud break time (2 weeks before the first subculture), with the highest shoot initiation (3.0 ± 0.2 cm), and after 4 weeks of incubation, the highest auxiliary shoot elongation (7.4 ± 0.1 cm). The significant effect of this hormone concentration also increases the nodule multiplication coefficient (NMC), which is 7.5. In vitro root response on the same propagation medium showed good growth with an average root length of 4.8 ± 0.2 cm. Acclimatization of plantlets was successful under ex vitro conditions and resulted in good growth after 2 and 3 months in the greenhouse. The advantage of applying the tissue culture method to gerunggang is that it can produce about seven times more seedlings from one explant in about 4 weeks. These results will be very useful for further research in the field and require a more intensive and comprehensive study.

Interspecific hybridization of Dendrobium mirbelianum x D. nindii or D. discolor, in vitro seed germination, seedling growth and plantlet acclimatization

Abstract. Maulida D, Yusnita Y, Hapsoro D, Agustiansyah A, Karyanto A. 2023. Interspecific hybridization of Dendrobium mirbelianum x D. nindii or D. discolor, in vitro seed germination, seedling growth and plantlet acclimatization. Biodiversitas 24: 3004-3011. Dendrobium mirbelianum Gaudich. (P1), D. nindii W.Hill (P2), and D. discolor Lindl. (P3) as a parent crossing are potentially resulting a new type of orchid as the novel breeding achievement. This study aimed to identify orchid crossing compatibility and evaluate the most effective and efficient media for hybrid seed germination and growth. The study consisted of three experiments, namely interspecific hybridization (experiment 1), in vitro hybrid seed germination (experiment 2), and in vitro growth of the hybrid seedlings (experiment 3). The first experiment was conducted by a simple modified line×tester mating design, and all experiments used a completely randomized design, with five replications in the first experiment and three replications in the second and third experiments. The first experiment presented all of the crossing emerging seed pods, but only hybrid seeds from cross D. mirbelianum x D. nindii and its reciprocal cross that potent to germinate in all tested media as the second experiment result. The third experiment showed FF+tryptone was the best media indicated by the highest and heaviest seedling after 8 months after sowing. All of the crossings resulted seed pods, however, only D. mirbelianum x D. nindii and its reciprocal cross that able to germinate in all tested media. Foliar fertilizer is the most recommended media for germinating hybrid orchid seeds, and FF+tryptone is the best for seedling growth.

Regeneration of Raja (Musa AAB Group) and Kepok (Musa ABB Group) bananas on various stages of in vitro culture

Banana group can be divided into two groups based on their method of its utilization. Banana group that can be eaten immediately after ripening is called "dessert banana", e.g., Raja, while the group that needs particular processing before consumption is called "plantain banana", e.g., Kepok. This study aimed to compare the growth of Raja banana with Kepok plantain through experiments at three stages of the in vitro culture media: the shoot initiation, shoot multiplication, and plantlet acclimatization, also to compare the growth of Raja bananas with Kepok plantains in response to cytokinins BAP and TDZ at shoot multiplication stage. Planting material was in the form of rhizomes that was prepared with the same size. The experiment was performed using a completely randomized design. Results showed that Kepok plantain could adapt faster to the media condition than Raja banana; the phenomenon was evident in the growing speed of Kepok during shoot initiation stage. The proportion of the B genome did not show a direct effect on shoot induction at the multiplication stage or enlargement and organ formation at the acclimatization stage. Shoot induction at the multiplication stage depended more on the composition of the media used. The combination of BAP 3 mg L-1 and TDZ 0.01 mg L-1 in MS media produced the best shoot induction rate, and TDZ 0.01 mg L-1 in MS media had the highest shoot elongation rate.
 Keywords: banana, BAP, genome, PGR, plantain, TDZ

Morpho-genetic characterization of diploid and tetraploid taro (Colocasia esculenta L. Schott) cv. Kaliurang - An Indonesian local cultivar

Kaliurang is one of the local taro cultivars in Indonesia, potentially due to its high productivity and delicacy. This study analysed morpho-genetic variation between one diploid and three tetraploid Kaliurang taro clones from <i>in vitro</i> polyploid induction after plantlet acclimatization in the greenhouse for 6 weeks. Plants’ morphological characters were analysed using the unweighted pair group method with arithmetic mean (UPGMA) method based on 50 characters according to the taro descriptor from the International Plant Genetic Resources Institute (IPGRI). Furthermore, a morphometric characterization based on the Euclidean distance of 17 digitations from mature leaves, was analysed with the Analysis Phylogenic and Evolution package in R software. DNA band pattern was also performed with ISSR to analyse the clone’s genetic variance. The results showed morpho-genetic character diversity in diploid and tetraploid plants. A plant morphological study revealed that 22 out of 50 characters were distinct, with similarity coefficients ranging from 0.35 to 0.78. Leaf geometric morphometric analysis showed changes in five digitations and formed three clusters. Twelve ISSR primers out of twenty amplified the sequence of the Kaliurang taro genome to yield two clusters with a similarity coefficient of 0.71–0.83. Based on these three characterization approaches, tetraploid clones (K2 and K3) consistently differed morphologically from diploid clones (K0).

Propagation of the Colombian genotype of cacao (Theobroma cacao L.) CNCh-12 by somatic embryogenesis

Cocoa production (Theobroma cacao L.) is essential globally and constitutes one of the leading export products for Colombia. Understanding the limitations faced by this crop in Latin American countries, it is required, among other aspects, to contribute to strengthening the first link in the production chain through efficient propagation methods and genetic improvement. Knowing that somatic embryogenesis is an alternative to conventional propagation and constitutes an obligatory step in a breeding platform, the objective of this work was to establish a somatic embryogenesis protocol until the plantlet acclimatization in the nursery for the regional genotype CNCh-12, a promising material with productivities higher than 2,000 kg/ha. Different protocols were evaluated, from callogenesis induction, through the expression of primary somatic embryos (PSE) followed by maturation and subsequent conversion to plantlet two types of explants (petal and staminode) and culture time (according to the stage). Additionally, the induction of secondary somatic embryos (SSE) was evaluated in two culture media (L and F). For CNCh-12, the petal was found as an appropriate explant, with a minimum time of 15 days in induction for PSE formation, without difference between the culture media F and L (22 average embryos). Embryo maturation was achieved in medium F after 30 days, followed by an additional 30 days for conversion to plantlet (52.83%). The concentration of salts to increase the conversion and development of the embryos was 1/5 of that used in F. The highest number of SSE was in the L medium. Finally, the ex-vitro adaptation was achieved when the plants were planted in 50:50 sand-coconut fiber and moistened weekly with Hoagland's solution (1:10). Keywords: Cacao, petals, in vitro propagation, plant growth regulators, somatic embryogenesis.

Somatic embryogenesis in two cassava (Manihot esculenta Crantz) genotypes

Plant breeding through hybridization in cassava is facing a problem due to inconsistent flowering, and also the donor genes controlling superior traits are limited. An alternative method of breeding is through genetic transformation, and regeneration via somatic embryogenesis is promising route to achieve this. As somatic embryogenesis in cassava is genotype-specific, in the present study a protocol has been developed for UJ-3 and BW-1 genotypes. Immature sterile leaves from 7-10 days axillary shoots in a pre-condition medium were used as an explant. Leaves were inoculated on Murashige and Skoog (MS) medium containing picloram (0.0, 7.5, 10.0, 12.5, and 15.0 mg/L) and 1-naphthalene acetic acid (NAA, 6 mg/L) for induction of somatic embryos (SEs). Genotype BW-1 showed best results as early callus formation time i.e. 8.04±0.32 days after induction (dai) compared to UJ-3 (8.67±2.13 dai). The callus fresh weight (0.64 g) was also higher in BW-1 than UJ-3 (0.38 g) after 4 weeks in callus induction medium (CIM), and the callus formation ranges between 85.19±3.70 to 96.30±3.70% for both genotypes. Subculturing embryogenic callus to MS+CuSO4 (4 µM) + picloram (6 mg/L) +NAA (0.5 mg/L) (SK1 medium) germinated maximum SEs in BW-1 (46.56±36.86), whereas the number was less for UJ-3 (11.89±11.90). Further, shoots were developed from green cotyledons followed by hardening and acclimatization of plantlets.

Influences of Organic Additives on Asymbiotic Seed Germination of Dendrobium cruentum Rchb. f. for In Vitro Micropropagation

Dendrobium cruentum Rchb. f., a commercial orchid in Thailand, faces the risk of extinction and should be conserved, and propagated for commercial. Therefore, the aim of this research was to identify a suitable VW medium supplemented with organic additives for the micropropagation of D. cruentum through asymbiotic seed germination. The VW media supplemented with separate organic additives (coconut water (CW) (100 mL/L), ‘Hom Thong’ banana homogenate (BH) (1000 mg/L), and potato homogenate (PH) (1000 mg/L) or its combination was determined, and the seed germination rate (%), protocorm formation, and plantlet development were observed. The results showed that a combination of BH and PH resulted in the highest seed germination (94.69 ± 1.55 %) when compared to basal VW (control). Protocorm formation was highest with CW alone (47.38 ± 7.17 %) and a combination of CW and PH (52.13 ± 6.20 %). Additionally, after 10 weeks of culture, supplementation with BH yielded the highest number of plantlets. However, after 24 weeks of culture, each organic additives gave the different developments of healthy plantlets. To investigate suitable potting media for acclimatization of well-grown plantlets in greenhouse conditions, 2 pieces of foam, dried coconut husk, and a combination of peat moss: Sphagnum moss: Pumice: Perlite (3:1:1:1) were investigated. The highest survival rate percentage was found in foam-planted plantlets (80 %). Ultimately, the effectively simple mediums containing organic additives and a one-step protocol were provided for the micropropagation of D. cruentum via seeds, and the derived information could be used for D. cruentum conservation and production. HIGHLIGHTS The effects of organic additives on asymbiotic seed germination for in vitro micropropagation of Dendrobium cruentum Rchb. f. was firstly reported The media supplemented with organic additives yield significantly the highest seed germination, protocorm formation, and plantlet formation and development of D. cruentum when compared to basal media In greenhouse conditions, 2 pieces of foam gave the highest survival rate percentage of plantlets (80 %) The practical and beneficial media supplemented with organic additives for micropropagation of D. cruentum was provided GRAPHICAL ABSTRACT

In vitro bioactive metabolite production and plant regeneration of medicinal plant Angelica sinensis

The root of Angelica sinensis (Oliv.) Diels is a traditional Chinese medicine (TCM) widely used for the cardio-cerebrovascular, anti-inflammatory, and anti-cancer agents, etc. Currently, the root yield is mainly limited by narrow geographical distribution, early bolting and flowering (EBF), continuous cropping obstacle, and germplasm degeneration. While two ancillary strategies to produce bioactive metabolites by bioreactor and innovate new germplasms by genome editing have not been conducted. Here is reported embryogenic callus induction, histomorphological structure identification, suspension cell culture, bioactive metabolite determination, shoot bud and root differentiation, and plantlet acclimatization at different treatments such as explants, hormones, and culture conditions. The embryogenic calli can be effectively induced (99.0%) from the root of aseptic seedlings by a combination of 2.0 mg/L IBA and 0.2 mg/L KT, and embryogenic cells including: three-cell, globular-, heart-, torpedo-, and cotyledon-shaped embryos were observed. The maximum growth rate, bioactive metabolites contents (i.e., ferulic acid, soluble sugar, flavonoids, and phenolic), and antioxidant capacities were observed at 9–12 d with inoculum density 40 g/L, 22 ℃ and 16/8 h light/dark. Robust plantlets can be obtained within 180 d after successive shoot bud and root differentiation as well as plantlet acclimation. Based on the strategies for the satisfaction of root demand, an effective and complete scheme is proposed for producing bioactive metabolites and regenerating plant of A. sinensis.

Evaluation of Different Substrates Compositions for Acclimatization of Tissue Culture Taro Plantlets in a Propagator

Evaluation of Different Substrates Compositions for Acclimatization of Tissue Culture Taro Plantlets in a Propagator

ACCLIMATIZATION OF CHERRY ROOTSTOCK KRYMSK-5 (VSL-2)

This article presents new aspects regarding theinfluence of nutrient media on acclimatization of cherry rootstock Krymsk-5 (VSL-2). Experiments are carried out for estimating the effect of nutrient media: MS, mMS DKW, WPM on acclimatization of cherry plantlets. The shoot length and width are measured periodically. The highest mean shoot length of Krymsk-5 in acclimatization were observed in DKW media: 4,55±0,22 cm after 30 days, and followed by118,87±2,56 cm growth after 160days in transferring to the field. The DKW nutrient media is found the most suitable among four nutrient media for acclimatization development of Krymsk®5 explants.

Design and Evaluation of a Smart Ex Vitro Acclimatization System for Tissue Culture Plantlets

One of the technological advancements in agricultural production is the tissue culture propagation technique, commonly used for mass multiplication and disease-free plants. The necessity for date palm tissue culture emerged from the inability of traditional propagation methods’ offshoots to meet the immediate demands for significant amounts of planting material for commercial cultivars. Tissue culture plantlets are produced in a protected aseptic in vitro environment where all growth variables are strictly controlled. The challenges occur when these plantlets are transferred to an ex vitro climate for acclimatization. Traditional glasshouses are frequently used; however, this has substantial mortality consequences. In the present study, a novel IoT-based automated ex vitro acclimatization system (E-VAS) was designed and evaluated for the acclimatization of date palm plantlets (cv. Khalas) to enhance their morpho-physiological attributes and reduce the mortality rate and the contamination risk through minimal human contact. The experimental findings showed that the morpho-physiological parameters of 6- and 12-month-old plants were higher when acclimatized in the prototype E-VAS compared to the traditional glasshouse acclimatization system (TGAS). The maximum plant mortality percentage occurred within the first month of the transfer from the in vitro to ex vitro environment in both systems, which gradually declined up to six months; after that, no significant plant mortality was observed. About 6% mortality was recorded in E-VAS, whereas 18% in TGAS within the first month of acclimatization. After six months of study, an overall 14% mortality was recorded in E-VAS compared to 41% in TGAS. The proposed automated system has a significant potential to address the growing demand for the rapid multiplication of tissue culture-produced planting materials since the plant survival rate and phenotype quality were much higher in E-VAS than in the conventional manual system that the present industry follows for commercial production.

MICROPROPAGATION OF GRAPEVINE (VITIS VINIFERA L.) CVS. RED GLOBE AND SUPERIOR

This study was conducted to develop a protocol for micropropagation of grapevine (Vitis vinifera L.) cultivars Red globe and Superior by investigating their response to three media Murashige and Skoog (MS), Chee and Pool (C2D), and Woody Plant Medium (WPM) during the establishment stage besides study the impact of four cytokinin types 6-benzylaminopurine (BA), 2-isopentyladenine (2iP), kinetin (Kin) and thidiazuron (TDZ) at various concentrations on the shoot multiplication as well as acclimatization of neoformed plantlets on several media. A completely randomized design (CRD) was used and data were analyzed by SASS 9.1. The results revealed that the WPM medium was optimum in terms of shoot length and leaf number (4.00 cm, 5.10) respectively. On the other side, Red globe gave the best results on both C2D and WPM media in average shoot length (4.38, 4.46 cm) and average leaf number (6.00, 5.42) respectively. In the multiplication stage and at 1 mgL-1, BA showed the longest shoot and leaf number (2.3, 6.67) respectively. While kin gave the maximum shoot length with a mean of 3.57 cm. Moreover, BA significantly at 1 mgL-1, 2iP at 2 mg L-1, Kin at 5 mgL-1 , and TDZ at 1 mgL-1 gave the highest values compared to other concentrations. Plantlets acclimatization results revealed that sterilized 1:1:1 (v:v) peatmoss+perlite+sand mix gave the highest survival rate (100.00%) and showed the best vegetative growth.

Micropropagation from Inflorescence Nodal Segments of Phalaenopsis and Acclimatization of Plantlets Using Different Substrates

Phalaenopsis is an orchid genus of great economic value in world floriculture. In vitro clonal propagation is the only large-scale feasible method for Phalaenopsis propagation, but it is difficult because of the low multiplication rate. The aim of this study was to evaluate the effect of types and concentrations of N6-benzyladenine (6-BA) and gibberellic acid (GA3) on the in vitro multiplication of shoots from inflorescence nodal segments (INS) of Phalaenopsis hybrids. INS with one axillary bud were inoculated in New Dogashima Medium with different combinations of BA and GA3. The results show that the treatment containing 1.0 mg L−1 BA and 1.5 mg L−1 GA3 showed the higher percentage of live inflorescence segments (71.48%) and a number of shoots (1.68 shoots/INS). The highest 6-BA concentration (4 mg L−1) tested in this study resulted in the best shoot multiplication rate (4.3). Contamination and browning of the INS tissues were the main difficulties identified for clonal propagation of Phalaenopsis. Successful in vitro rooting occurred on half-strength Murashige and Skoog medium (100%), and acclimatization (100%) was obtained independent of the substrates. However, the best gains in number of roots, leaves, chlorophyll content, and fresh weight of plantlets were achieved using vermiculite.

Colonization with non-mycorrhizal culturable endophytic fungi enhances orchid growth and indole acetic acid production

BackgroundSymbiotic associations of endophytic fungi have been proved by possessing an ability to produce hormones and metabolites for their host plant. Members of the Orchidaceae are obligate mycorrhizal species but a non-mycorrhizal association needs more investigation for their ability to promote plant growth and produce plant growth hormones. In the present study, endophytic fungi were isolated from the roots of Dendrobium longicornu Lindl., to investigate the root colonizing activity and role in plant growth and development.ResultsAmong 23 fungal isolates were identified both by morphological and molecular technique as Penicillium sp., Fusarium sp., Coniochaeta sp., Alternaria sp., and Cladosporium sp. The dominate species were Coniochaeta sp. and Cladosporium sp. The dominant species as per the isolation was Coniochaeta sp. These fungal strains were screened for growth-promoting activity of Cymbidium aloifolium (plantlet) consider as cross genus interaction and Dendrobium longicornu (protocorms) as a host plant in in-vitro condition. Importantly, Cladosporium sp., and Coniochaeta sp. showed successful colonization and peloton formation with roots of C. aloifolium. Moreover, it also enhanced acclimatization of plantlets. Fungal elicitors from nine fungal isolates enhanced the growth of the in vitro grown protocorms of D. longicornu. Key bioactive compounds detected in the fungal colonized plant extract were 2H-pyran-2-one, Cyclopropanecarboxylic acid, Oleic Acid and d-Mannitol, which may have a potential role in plant-microbe interaction. All fungal endophytes were able to synthesize the indole acetic acid (IAA) in presence of tryptophan. Moreover, fungal extract DLCCR7 treated with DL-tryptophan yielded a greater IAA concentration of 43 μg per ml than the other extracts. The iaaM gene involved in IAA synthesis pathway was amplified using iaaM gene primers successfully from Alternaria sp., Cladosporium sp., and Coniochaeta sp.ConclusionsHence, this study confirms the production of IAA by endophytes and demonstrated their host as well as cross-genus plant growth-promoting potential by producing metabolites required for the growth of the plant.