Combinations Of Growth Regulators Research Articles

A highly efficient organogenesis system based on 6-benzylaminopurine and indole-6-butyric acid in Suaeda glauca-a medicinal halophyte under varying photoperiods

Suaeda glauca (Bunge) is a pivotal halophyte species, well-known for its rich nutrient content and its importance as a superior vegetable and oil crop, offering significant health benefits for both human and animal consumption. However, the absence of an efficient regeneration technique has severely hindered its genetic development. Consequently, there is an urgent need to establish an effective in vitro organogenesis initiation method for this valuable plant. In this study, our primary objective was to develop a comprehensive protocol for micropropagating S. glauca, primarily capitalizing on the synergistic effects of 6-benzylaminopurine (6-BAP) and indole-6-butyric acid (IBA). We explored the impact of different combinations of 6-benzylaminopurine (6-BAP), 2,4-dichloroacetic acid (2,4-D), and IBA on callus induction, organogenesis, and rooting using various explants (cotyledons, hypocotyls, and leaves) under two different photoperiod regimes during in vitro culture. Our results unveiled noteworthy variations in several variables related to organogenesis. The optimal combination of plant growth regulators (PGRs) for inducing embryonic callus from cotyledon (COT) was pinpointed at 4.44 μM 6-BAP and 2.71 μM 2,4-D. By employing 6-BAP concentrations ranging from 8.88 μM to 13.33 μM, alongside 0.49 μM IBA, 3% sucrose, and 0.3% phytagel in full MS media under light conditions, we achieved a remarkable 100% regeneration rate through the direct organogenesis pathway. Our findings underscore the pivotal role of 6-BAP in triggering multiple shoots and attaining a 3.6% callus differentiation rate, while 0.98 μM IBA resulted in a 65.28% root induction rate, facilitating the successful acclimatization of plants. Based on the synergistic effects of 6-BAP and IBA, we propose a robust protocol for S. glauca organogenesis, which holds great promise for streamlining micropropagation in S. glauca tissue culture. This standardized protocol has the potential to advance genetic improvement and promote the commercial cultivation of S. glauca as a valuable halophyte species.

Mass Scale Micropropagation Of Andrographis Paniculata (Burm. F.) Wall Ex Nees

A reliable and efficient protocol was developed for in vitro propagation of Andrographis paniculata (Burm. f.) Wall ex Nees with the use of nodal and shoot tip explants. Nodal segments and shoot apex of in vitro grown seedlings were cultured on agar solidified MS medium supplemented with different concentrations and combinations of plant growth regulators (PGRs). Both the explants underwent direct organogenesis and produced multiple shoot buds. In case of shoot apex, maximum number of multiple shoot buds were formed when cultured on MS medium containing 1.5 mg/l Kn + 1.0 mg/l IAA. But nodal segments produced highest number of shoot buds on MS medium fortified with 1.5 mg/l BAP + 1.0 mg/l IAA. Multiple shoot buds underwent rapid elongation on elongation media and maximum elongation took place on MS medium fortified with 2.0 mg/l Kn + 1.5 mg/l IAA. Elongated shoot buds, on further culture in rooting media, produced strong and stout root systems. Half strength MS medium fortified with 2.0 mg/l IAA was most effective for induction and proliferation of roots. The healthy complete plantlets were successfully acclimatized and established in outside pots through successive phases of acclimatization. The Chittagong Univ. J. B. Sci.,Vol. 7(1 &2):121- 130, 2012.

Biochemical properties and pigment contents of Satureja genotypes affected by plant growth regulators and temperature stress.

There is little data, to our knowledge, on the biochemical properties of different Satureja sp. genotypes affected by plant growth regulators (PGR) under temperature stress. A split plot research on the basis of a complete randomized block design with three replicates examining temperature stress (planting dates, 8th of April, May and June) (main factor), and the factorial combination of plant growth regulators (PGR, control (CO), gibberellic acid (GA), fertilization (MI), and amino acid (A)), and genotypes (Khuzestani, Mutika, and Bakhtiari) on plant biochemical properties, was conducted. Plant pigment contents (chlorophyll a, and b and carotenoids (car)), antioxidant activity (catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GP)), and leaf protein were determined. Treatments significantly and differently affected the genotypes performance. PD3 and PD1resulted in significantly higher activity of APX (0.059 U. mg-1) and GP (0.190 U. mg-1), respectively (P ≤ 0.05). Temperature stress significantly affected plant CAT activity (U. mg-1) at PD1 (0.084) and PD3 (0.820). Higher temperature significantly enhanced leaf Pro, MI increased plant APX (0.054) and CAT activities (0.111 U. mg-1) significantly, and GA resulted in the highest and significantly different GP activity (0.186 U. mL-1). Treatments T1 and T3 significantly enhanced Chla and Car content, and MI resulted in significantly higher Chlb content (0.085mgg-1 leaf fresh weight). Car and CAT are the two most sensitive biochemical traits under temperature stress and can more effectively regulate Satureja growth and activity. It is possible to alleviate temperature stress on Satureja biochemical properties by the tested PGR.

A Comprehensive Study on the Micropropagation of Costus igneus: Media Composition, Growth, and Development

Costus igneus, commonly known as insulin plant, is an ornamental plant valued for its spiral ginger- like foliage and medicinal properties. Micropropagation is an efficient method for rapid multiplication of Costus igneus. This study aims to determine the optimal media composition and culture conditions for in vitro propagation of C. igneus. Axillary bud explants were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations and combinations of plant growth regulators including auxins (indole-3-acetic acid, indole-3-butyric acid and naphthaleneacetic acid) and cytokinins (6- benzylaminopurine and kinetin). Microshoots cultured on MS + 1.5 mg/L BAP showed the highest shoot proliferation rate (98%) and maximum number of shoots per explant (12.6). Elongated microshoots were rooted on half-strength MS medium supplemented with different auxins. The highest rooting percentage (95%) and maximum number of roots per shoot (9.8) were observed on medium containing 2.5 mg/L IBA. The regenerated plantlets were acclimatized and successfully transferred to pots with 80% survival rate. Morphological and phytochemical analysis showed no significant differences between the in vitro propagated and mother plants. This study demonstrates the potential of micropropagation for large scale production of quality planting material of C. igneus. Further studies on genetic and epigenetic stability are recommended to validate this protocol for commercial applications.

In Vitro Shoot Multiplication and Rooting of 'Kashan' and 'Hervy Azerbaijan' Damask Rose (Rosa damascena Mill.) Genotypes for Cosmetic and Ornamental Applications.

The damask rose (Rosa damascena Mill.) is an ornamental-medicinal plant from the Rosaceae family, and its aromatic compounds and essential oils are applied globally in the food, cosmetic, and pharmaceutical industries. Due to its economic value, this research aimed to establish a protocol for an efficient, rapid, and cost-effective method for in vitro shoot multiplication and rooting of the R. damascena 'Kashan' and 'Hervy Azerbaijan' genotypes. Nodal segments (as primary explants) were cultured on the Murashige and Skoog (MS) medium with combinations of various plant growth regulators (PGRs) such as gibberellic acid (GA3), 6-benzylaminopurine (BAP), and indole-3-butyric acid (IBA), as well as a PGR-like substance, phloroglucinol (PG), vitamins such as ascorbic acid (AA), and activated carbon in the form of active charcoal (AC). For the establishment stage, 0.1 mg·L-1 PG, 0.2 mg·L-1 GA3, and 1 mg·L-1 BAP were added to the media. Secondary explants (nodal segments containing axillary buds produced from primary explants) were obtained after 30 days of in vitro culture and transferred to the proliferation media supplemented with different concentrations of BAP (0, 0.5, 1, 1.5, 2, and 2.5 mg·L-1) and GA3 (0, 0.1, 0.2, 0.4, 0.8, and 1 mg·L-1) together with 0.1 mg·L-1 PG and 20 mg·L-1 of AA. The rooting media were augmented with different concentrations of BAP and GA3 with 0.1 mg·L-1 of IBA, PG and 20 mg·L-1 of AA and AC. The results showed that the highest regeneration coefficient (4.29 and 4.28) and the largest number of leaves (23.33-24.33) were obtained in the explants grown on the medium supplemented with 2 mg·L-1 BAP and 0.4 mg·L-1 GA3 for the 'Kashan' and 'Hervy Azerbaijan' genotypes, respectively. Likewise, this PGR combination provided the shortest time until bud break (approximately 6.5 days) and root emergence (approximately 10 days) in both genotypes. The highest number of shoots (4.78 per explant) and roots (3.96) was achieved in this medium in the 'Kashan' rose. Stem and root lengths, as well as stem and root fresh and dry weights, were also analyzed. In most measured traits, the lowest values were found in the PGRs-free control medium. Rooted plantlets were transferred to pots filled with perlite and peat moss in a 2:1 proportion and were acclimatized to ambient greenhouse conditions with a mean 90.12% survival rate. This research contributes significantly to our understanding of Damask rose propagation and has practical implications for the cosmetic and ornamental plant industries. By offering insights into the manipulation of regeneration processes, our study opens up new possibilities for the effective production of high-quality plant material.

Effect of Different Concentrations of Auxin as Well as Cytokinin on Shoot Initiation, Formation and Multiplication of Pepino (Solanum muricatum Ait.) cv. Valentia with MS Semi-solid Medium

The pepino (Solanum muricatum Aiton) is conventionally propagated through vegetative means. But, this approach of propagation is not feasible for commercial production of plants and has at more time the chances of reduction yield. Therefore, the availability of quality planting material is of urgent need. Recently, there has been a promising approach for pepino multiplication at large scales through tissue culture because it generates a large number of contamination free plantlets in a minimum space and time. The combination of different growth regulators may be tried to maximize the initiation, growth and development of shoot in commercial propagation of pepino plants. The Minimum days taken for shoot initiation (5.21 days) was noted under BAP 3.00 mgl-1 + IBA 0.50 ppm, and minimum days taken for shoot development (40.82 days) was noted under of BAP 3.00 ppm + IBA 1.00 ppm. The highest length of shoot (9.52 cm) was produced in media supplemented with BAP 3.00 ppm + IBA 1.00 ppm. Maximum percent of developed shoots obtained from the established culture (67.79) was noted under the treatment of BAP 3.00 ppm + IBA 1.00 ppm; While maximum shoots per explants/ innoculums from the established culture (4.06) was noted under the treatment of BAP 3.00 ppm + IBA 1.00 ppm. Maximum number of leaves / plantlet from the established culture (10.85) was noted under the treatment of BAP 3.00 ppm + IBA 1.00 ppm and maximum fresh weight (mg) of shoot / plantlet obtained from the established culture (26.05 mg) was noted under the treatment of BAP 3.00 ppm + IBA 1.00 ppm.

Establishment of plant regeneration protocol through callus induction of sugarcane (Saccharum officinarum l.) var. China using leaf-sheath

Establishment of a plant regeneration system through direct organogenesis or via callus is also a prerequisite to further in vitro genetic manipulation of the cultivar through somaclonal variation, in vitro mutagenesis and genetic transformation. Production of sufficient numbers of plants of a unique genotype is possible using in vitro culture system. In this study, the effect of various concentrations and combinations of plant growth regulators for in vitro regeneration of sugarcane via callus was described using leaf-sheath as explants. Thus, a reproducible protocol for induction of callus and regeneration into plantlets were developed in sugarcane var. china using leaf-sheath as explants. Potential callus induction was observed on MS medium supplemented with 4.5 mg/l 2,4-D, in which 80% explants induced callus after culture initiation of 90 days. Shoot formation from the callus was optimum on MS + 1.0 mg/l GA3 + 0.5 mg/l Kin., in which 70% of the cultured calli formed shoots. The average number of shoot formed per culture callus was 27.0 ± 2.50 and the average shoot length of 6.5 ± 0.50 cm were achieved in this medium after culture of 60 days. Regenerated shoots rooted well when they were transferred into half strength of MS + 2.50 mg/l NAA, in which 90% shoots rooted within 30 days of culture. The average number of root produced per shoot was 18.0 ± 2.25 and the average root length of 7.50 ± 1.20 cm were observed in this medium. Ninety percent of the in vitro raised plantlets were survived in the natural environment.

Rapid Multiplication of Geographical Indication (GI) Tagged Mysore Mallige (Jasminum azoricum L.) Using Single Node through In vitro Culture

Aims: The present study was undertaken to rapid multiplication of (GI) tagged Mysore Mallige (Jasminum azoricum L.) using single node through in vitro culture. Study Design: The present study follow Completely Randomized Design (CRD). Place and Duration of Study: The study was conducted at the Plant Tissue Culture Laboratory, Department of Horticulture, University of Agricultural Sciences, Gandhi Krishi Vignana Kendra, Bengaluru, from 2020 to 21. Methodology: Single node cutting from the young shoots of field growing plants were used as explants to conduct the experiment. The explants were sterilized and placed on MS medium supplemented with different concentrations and combinations of growth regulators, namely BAP and Kinetin. Results: Among the different combinations of growth regulators, the combination of BAP 1.5 mg L-1 and Kin 1.5 mg L-1 produced maximum number of shoots from single node. Very low intensity of callus formation was observed from the cut ends of single node explants that were cultured on half strength MS medium consisting of 1.5 mg L-1 BAP + 0.0 mg L-1 Kin and 1.5 mg L-1 BAP + 1.0 mg L-1 Kin. Conclusion: The use of growth regulators such as BAP and KIN is reliable for shoot regeneration even when the field explants are used.

Exploring somatic embryogenesis in Ajuga multiflora Bunge: Profiling lipophilic metabolites via HPLC, GC-FID, and GCMS– analysis

The present study aims to assess the effect of different concentrations of auxins and combinations of plant growth regulators (PGRs), specifically auxin and cytokinin, on somatic embryogenesis in Ajuga multiflora. We also aim to compare the lipophilic metabolite profiles, such as carotenoids (CAs), fatty acids (FAs), phytosterols (PSs), and tocopherols (TPs), in globular somatic embryos (SEs), germinated SEs, and shoots of SEs derived plantlets. This assessment is carried out utilizing high performance liquid chromatography, gas chromatography-flame-ionization detection, and gas chromatography–mass spectrometry techniques. The results reveal that the application of 2,4-dichlorophenoxyacetic acid (2,4-D) had the most significant impact on somatic embryogenesis, inducing both SE initiation (34.4%) and the number of SEs (3.5) per explant. Among the explants used, leaf explants were found to be the most effective for SE induction (SEI). Additionally, the study explores the combined effect of 2,4-D and cytokinins (N6-benzyladenine, N6-BA, or 1-phenyl-3-(1,2,3-thiadiazol-5-yl) urea, TDZ) on somatic embryogenesis, highlighting optimal conditions for SEI percentages and the number of SEs per explant. The maximum SE induction rate (100%) and the number of SEs (45.9) per leaf explant were obtained on an SEI medium with 30 µM of 2,4-D and 2.3 µM of TDZ. The maturation and conversion of SEs were also examined, emphasizing the role of GA3 in achieving the highest conversion percentage (94.0 ± 2.7 at 0.8 µM GA3). Furthermore, the study details the biochemical composition during various stages of somatic embryogenesis, including CAs, TPs, PSs, and FAs. Globular SEs displayed comparatively lower concentrations of CAs than their germinated counterparts and shoots from SE-derived plantlets, while the total PSs content remained relatively consistent across all stages. Conversely, fatty acids tended to accumulate more in globular SEs, with the exception of α-Linolenic acid. These findings provide valuable insights into the optimization of somatic embryogenesis protocols in A. multiflora, with implications for plant tissue culture, regeneration and lipophilic metabolites production.

Direct Plant Regeneration from Nodal Explants of Grapefruit (Citrus paradisi Macfad.)

Aims: The present study was undertaken to develop a protocol for in vitro regeneration and multiplication of disease-free quality planting material of Grapefruit (Citrus paradisi Macfad.). Study Design: Completely Randomized Design (CRD) Place and Duration of Study: The study was conducted at the Plant Tissue Culture Laboratory, Department of Horticulture, University of Agricultural Sciences, Gandhi Krishi Vignana Kendra, Bengaluru, from 2020 to 21. Methodology: Nodal segments from the young shoots of field growing plants were used as explants to conduct the experiment. The explants were sterilized and placed on MS medium supplemented with different concentrations and combinations of growth regulators, namely BAP, Kinetin and Gibberellic acid. Results: Among the different combinations of growth regulators, the combination of BAP 1.0 mgL-1 and GA3 3.0 mgL-1 produced maximum number of shoots (7) from nodal segments Conclusion: The use of growth regulators such as BAP and GA3 is reliable for shoot regeneration even when the field explants are used.

An Efficient Method for the Propagation of Bougainvillea glabra ‘New River’ (Nyctaginaceae) from In Vitro Stem Segments

Bougainvillea, an evergreen climbing shrub of the Nyctaginaceae family, holds significant ornamental, economic, and medicinal value. Bougainvillea glabra ‘New River’ is widely used in landscapes due to its strong adaptability to the environment, abundance of flowers, and frequent flowering. Traditionally, Bougainvillea glabra ‘New River’ cultivation has relied on methods such as cuttings or grafting, with limited research on in vitro tissue culture propagation. This study aimed to optimize the tissue culture system, exploring a combination of plant growth regulators (PGRs) for Bougainvillea regeneration from in vitro stem segments. The Murashige and Skoog (MS) medium supplemented with indole-3-butyric acid (IBA), 6-benzylaminopurine (6-BA), and 1-naphthlcetic acid (NAA) was employed. The optimal sterilization of Bougainvillea stem segments involved a 30 s treatment with 75% alcohol and 10 min with 1% NaClO. The synergistic effect of 0.1 mg·L−1 of NAA and 2.5 mg·L−1 of 6-BA maximized the shoot sprouting frequency, while 2.5 mg·L−1 of 6-BA and 0.1 mg·L−1 of NAA produced the maximum shoots. Furthermore, 1.5 mg·L−1 of IBA and 0.1 mg·L−1 of NAA induced the highest rooting levels. This work demonstrates the successful adaptation of a greenhouse environment to efficiently regenerate plants in vitro from stem segments. This approach allows for the mass production of Bougainvillea glabra ‘New River’.

Effect of Different Plant Growth Regulators on In-vitro Micropropagation of Banana Cultivar Grand Naine (Musa spp.)

Banana (Musa sapientum) is one of the most important fruit crop cultivated in India. It is widely grown in more than 150 countries, producing on an average of 105 million tons of fruit per annum. Grand naine Banana variety is the most commonly cultivated banana with high yielding plantain. This variety mainly grown in the region of Uttar Pradesh state. Present study mainly focuses on the in-vitro micropropagation method which is described for banana cv. Grand naine. For this study, healthy sword suckers of three months old banana plantlets was used as explants. The explants was sterilized thoroughly and cultured on MS (Murashige and Skoog) media supplemented with the different concentration and combination of auxin and cytokinin like BAP, IAA and NAA which were used for the optimization of best plant growth regulator combination for multiple shoot generation and shoot growth. Among all the tested cytokinin 5 mg/l BAP along with 1mg/l IAA in medium concentration performed well and produced healthy shoots further at higher concentration of all tested cytokinin showed declining effect within the growth parameters. For the rooting purpose, MS media was supplemented with different levels of IBA, IAA and NAA. Results indicated that rooting was highly promoted in the medium supplemented with 0.5 mg/L IAA + 1.5 mg/L IBA.

An Efficient Agrobacterium-Mediated Genetic Transformation System for Gene Editing in Strawberry (Fragaria × ananassa).

The octoploid-cultivated strawberry variety Benihope (Fragaria × ananassa Duch cv. Benihope) is an important commercial plant. It is highly susceptible to different diseases, which ultimately leads to a reduction in yield. Gene-editing methods, such as CRISPR/Cas9, demonstrate potential for improving disease resistance in the strawberry cv. Benihope. Establishing a plant regeneration system suitable for CRISPR/Cas9 gene editing is crucial for obtaining transgenic plants on a large scale. This research established a callus induction and plant regeneration system for Agrobacterium-mediated CRISPR/Cas9 gene editing in strawberry cv. Benihope by evaluating multiple types of explants and various plant growth regulators throughout the entire tissue culture process. The results showed that the efficiency of callus induction is strongly influenced by the type of explant and is highly sensitive to the combination of plant growth regulators. Among the different plant growth regulators employed, thidiazuron (TDZ), in combination with 2,4-dichlorophenoxyacetic acid (2,4-D), effectively induced callus formation and plant regeneration from explants derived from nutrient tissues such as runner tips and crowns. In addition, the regeneration experiment demonstrated that the addition of polyvinylpyrrolidone (PVPP) to the shoot regeneration medium could inhibit tissue browning. The gene-edited plants in which some or all of the Fvb7-1, Fvb7-2, Fvb7-3, and Fvb7-4 genes in the MLO (Mildew resistance Locus O) gene family were knocked out by CRISPR/Cas9 system were obtained by applying the plant regeneration system developed in this study.

Morphogenesis Response of Leaf and Petiole Explant of Rootstock Apple (Malus sylvestris Mill.) to Auxin and Cytokinin

Rootstock apple is a type of plant used in grafting propagation. Research related to the response of morphogenesis in this plant has not been widely carried out. The aim of this research was to study the effect of auxin and cytokinin ratio on the morphogenesis response of leaf and petioles explants of rootstock apple and to study variations in the ratio of auxin and cytokinin with the best response. The study used a 2-factorial Completely Randomized Design (CRD) with variations in the types of explants and combinations of plants growth regulators (PGR) in the culture medium. There were 12 treatments with five repetitions. Explants in the form of young apple leaf (third leaf) and petiole rootstock that had been sterilized and cut with a size of 5x5 mm for the leaf and 5 mm long for the petiole were inoculated into MS medium with cytokinin in the form of BAP (1 ppm) combined with auxin, IBA (0, 0.1, 0.2, 0.3, 0.4, 0.5 ppm). Each culture bottle contains five explants. The results showed that the average leaf explant was capable of producing 34% callus. Meanwhile, petiole explants produced 4% callus. Callus began to form on leaf and petiole explants on the 26th and 42nd days after inoculation respectively. Most calluses have a compact texture with variations in green, yellowish white, and brownish green. The PGR combination with the highest percentage of callus formation in leaf explants was found in the BAP 1 ppm + IBA 0.4 ppm treatment, while the petiole was in the BAP 1 ppm + IBA 0.3 ppm treatment

Suspension culture of stem cells established of Calendula officinalis L.

Plant stem cell cultures have so far been established in only a few plant species using cambial meristematic cells. The presence of stem cells or stem cell-like cells in other organs and tissues of the plant body, as well as the possibility of de novo generation of meristematic cells from differentiated cells, allow to consider the establishment of stem cell cultures in a broader range of species. This study aimed to establish a stem cell culture of the medicinal plant Calendula officinalis L. Callus tissues were induced from leaf and root explants, and already at this stage, stem and dedifferentiated cells could be identified. The cell suspension cultures established both from the root- and leaf-derived calli contained a high proportion of stem cells (92–93% and 72–73%, respectively). The most effective combination of growth regulators for the development of stem cells in calli as well as cell cultures was 1.0 mg/L 2,4-D and 0.5 mg/L BAP. The highest amount of stem cells (5.60–5.72 × 105) was in cell suspension derived from the roots. An effective protocol for the establishment of marigold stem cell suspension culture was developed. The ratio of root-derived stem cells against dedifferentiated cells exceeded 90%.

Plant growth regulators improve root growth of rice seedlings after mechanical transplanting and increase grain yield

Summary Enhancing seedling quality and promoting root growth post-transplantation are crucial for improving mechanically transplanted rice productivity. Here we investigated the impact of various plant growth regulators on hybrid and conventional rice varieties. Treatments, including two-diethylaminoethyl hexanoate (DA-6, 10 mg L−1), a combination of potassium 3-indole-butyrate + potassium 1-naphthylacetate + 6-benzylaminopurine (C3, 50 + 50 + 10 mg L−1), potassium 3-indole-butyrate + potassium 1-naphthylacetate + 1-triacontanol (C4, 50 + 50 + 50 mg L−1), potassium 3-indole-butyrate + potassium 1-naphthylacetate + 1.8% sodium nitrophenolate (C5, 50 + 50 + 1 mg L−1), and a combination of potassium 3-indole-butyrate + potassium 1-naphthylacetate + 1.8% sodium nitrophenolate + DA-6 (C6, 50 + 50 + 1 + 10 mg L−1), were sprayed either 3 or 10 days before transplanting. Seedlings sprayed 10 days before transplanting exhibited a higher number of white roots and total roots at the returning green stage, along with increased grain yield, irrespective of the plant growth regulator used. The C6 combination emerged as the most effective treatment, enhancing the growth of both hybrid and conventional rice seedlings, accelerating the growth rate of white roots and total roots, and increasing the length of the longest white root during the greening period, ultimately resulting in higher grain yield. Our findings demonstrate that pre-transplantation application of a combination of plant growth regulators positively influences rice seedling growth.

In Vitro Seed Germination and Seedling Development of Mimusops laurifolia (Forssk.) Friis.: An Endangered Plant Species

Mimusops laurifolia (Forssk.) Friis is an endangered medicinal plant and natural propagation of this plant through seeds is found to be very difficult due to its hard seed coat. To conquer this problem, an efficient in vitro seed germination as well as subsequent in vitro regeneration technique has been developed in conserving this endangered plant species. Seed germination was achieved on half strength of MS (HMS), full strength MS (FMS) and MS medium supplemented with different concentration and combination of Plant Growth Regulators (PGR) like BA, Kn and GA. The highest seed germination rate (18%) was obtained from water soaking de-coated seeds inoculated on full strength of MS (FMS), on the other hand, 12% germination of seeds was recorded on HMS medium, but both the conditions required more than 90 days to germinate. A similar rate of germination was also found on MS with PGRs, but it required 55-60 days. Best responses towards seed germination with elongated shoots (2.8 cm and 3.0 cm) were obtained when seeds were inoculated on MS with 3.0 mg/l BA, 0.5 mg/l Kn and 0.2 mg/l GA. After a long period of period of 8 months following germination, seedlings produced elongated tap roots only. Rooted seedlings were successfully transferred to soil for their further growth and development. Apart from this, for in vitro regeneration of shoots, explants of nodal segments and shoot tips from the natural plant were cultured on woody plant medium (WPM) supplemented with various combination and concentration of BAP, Kn and TDZ. In these cases, there was no positive response recorded towards the initiation of shoots from nodal segment and shoot tips. Plant Tissue Cult. & Biotech. 33(2): 143-153, 2023 (December)

Effects of different explant and growth regulator combinations on in vitro propagation of Poinsettia (Euphorbia pulcherrima Willd.)

The aim of the research is to develop a suitable micropropagation protocol for the Poinsettia (Euphorbia pulcherrima Willd.) plant, which is used as an ornamental plant. In the sterilization step, mercuric chloride together with sodium hypochlorite is approved as the best option. Thus, contamination of explants is eliminated. At the shoot propagation stage, BA is absolutely necessary as all doses of BA increased shoot propagation compared to the control. The highest number of shoots per explant (2.62 shoots/explant) and the longest shoots (2.16 cm) were obtained from 1.0 mg.L-1 BA medium. The highest number of leaves (20.41 leaves/explant) was obtained from 2.0 mg.L-1 BA medium. Kinetin was also effective when adding different concentrations to the culture medium compared to the control. In general, BA is more effective than Kinetin in these parameters. Kinetin, on the other hand, performed much better than BA in terms of shoot number. On the other hand, the highest rooting percentage (58.2%) was obtained from the addition of 0.3 mg.L-1 NAA. The highest root number (5.10 roots/explant) was obtained by adding 0.1 mg.L-1 NAA. Good performance was found in the acclimatization phase with plantlets transferred to the soil with a high survival rate reaching 100%. Most of the plantlets started growing well. The plantlets grew well and did not show morphological abnormalities. In addition, a successful plant regeneration was achieved by adding 1.0 mg.L-1 BA and 0.5 mg.L-1 NAA on the callus produced in leaf disc explants and a very good organogenesis was determined in terms of roots and shoots.

Trends in the Tissue Culture Techniques and the Synthesis of Bioactive Compounds in Eurycoma longifolia Jack-Current Status and Future Perspectives.

Over the last two decades, there has been a concerted effort by researchers to mass propagate Eurycoma longifolia and improve the yield of its very important and sought-after anti-cancer and aphrodisiac bioactive compounds. To achieve this, various techniques have been used to mass propagate and improve the yield of these bioactive compounds in tissue cultures. These techniques include the optimization of media conditions and application of various types and combinations of plant growth regulators (PGRs). In addition, some elicitation techniques have been used to improve the synthesis of these bioactive compounds. However, in comparison with other herbal species with similar economic importance, many techniques have not been applied to E. longifolia. Adopting the most recent methodologies would ensure efficiency and sustainability in the in vitro production of bioactive compounds in E. longifolia. Therefore, in this review, we present an up-to-date record on the success stories in the tissue culture techniques and synthesis of bioactive compounds. In addition, we attempted to identify some of the missing links on the road to the effective and sustainable biotechnological utilization of this super important biological resource.

Studies on Improving the Efficiency of Somatic Embryogenesis in Grapevine (Vitis vinifera L.) and Optimising Ethyl Methanesulfonate Treatment for Mutation Induction.

Somatic embryogenesis (SE) has many applications in grapevine biotechnology including micropropagation, eradicating viral infections from infected cultivars, mass production of hypocotyl explants for micrografting, as a continuous source for haploid and doubled haploid plants, and for germplasm conservation. It is so far the only pathway for the genetic modification of grapevines through transformation. The single-cell origin of somatic embryos makes them an ideal explant for mutation breeding as the resulting mutants will be chimera-free. In the present research, two combinations of plant growth regulators and different explants from flower buds at two stages of maturity were tested in regard to the efficiency of callusing and embryo formation from the callus produced in three white grape cultivars. Also, the treatment of somatic embryos with the chemical mutagen ethyl methanesulfonate (EMS) was optimised. Medium 2339 supplemented with β-naphthoxyacetic acid (5 μM) and 6-benzylaminopurine (BAP-9.0 μM) produced significantly more calluses than medium 2337 supplemented with 2,4-dichlorophenoxyacetic acid (4.5 µM) and BAP (8.9 µM) in all explants. The calluses produced on medium 2337 were harder and more granular and produced more SEs. Although the stage of the maturity of floral bud did not have a significant effect on the callusing of the explants, calluses produced from immature floral bud explants in the premeiotic stage produced significantly more SEs than those from more mature floral buds. Overall, immature ovaries and cut floral buds exposing the cut ends of filaments, style, etc., tested for the first time in grapevine SE, produced the highest percentage of embryogenic calluses. It is much more efficient to cut the floral bud and culture than previously reported explants such as anthers, ovaries, stigmas and styles during the short flowering period when the immature flower buds are available. When the somatic embryos of the three cultivars were incubated for one hour with 0.1% EMS, their germination was reduced by 50%; an ideal treatment considered to obtain a high frequency of mutations for screening. Our research findings will facilitate more efficient SE induction in grapevines and inducing mutations for improving individual traits without altering the genetic background of the cultivar.