Highest Shoot Formation Research Articles

Effect of Different Hormones Concentration on In vitro Regeneration of Apricot Cultivars

The use of modern breeding methods along with appropriate cultivation techniques facilitates the acquisition and multiplication of varieties that possess the desired characteristics. Therefore, efforts towards the in vitro propagation of woody plants are increasing day by day. Today, plants such as Malus, Prunus, Pyrus, Ribes, Rubus, etc., can be successfully propagated in vitro. Apricot stands out as a stubborn species among Prunus types for shoot regeneration and genetic transformation. In this context, this study aims to determine how different plant growth regulators affect shoot regeneration of some native apricot varieties, which hold significant importance in apricot cultivation in our country. In the conducted study, mature cotyledons of Kabaaşı, Hacıhaliloğlu, and Hasanbey apricot varieties were used along with the culture medium consisting of MS. Different doses and ratios of plant growth regulators, including BAP and TDZ, in combination with NAA and GA3, were added to the culture media. At the end of the in vitro study, the callus and primordium formation rate (%), bud and shoot formation rate (%) and number of shoots per explant were recorded. According to the results, the variety with the highest callus formation was Kabaaşı, followed by Hasanbey and Hacıhaliloğlu. In all three varieties, the rate of callus formation decreased in media containing GA3. Regarding the stage of shoot regeneration from callus, the highest shoot formation with an average of 4 shoots per explant was observed in the Kabaaşı variety in the TDZ (1.0 mgL-1) + NAA (0.25 mgL-1) and TDZ (1.0 mgL-1) + NAA (0.50 mgL-1) media. Looking at the other varieties, the highest number of shoots, 1.6 shoots per explant, was obtained from the TDZ (2.0 mgL-1) + NAA (0.25 mgL-1) medium in Hasanbey and Hacıhaliloğlu varieties. As a result of the findings, the Kabaaşı variety showed the best result in terms of the regeneration capacity of apricot varieties. In contrast the best regeneration medium was obtained from the combinations of TDZ and NAA.

Shoot regeneration in Nepenthes mirabilis as affected by flurprimidol and GA3 application

Abstract. Dwiati M, Widodo P, Susanto AH. 2023. Shoot regeneration in Nepenthes mirabilis as affected by flurprimidol and GA3 application. Biodiversitas 24: 4168-4174. Nepenthes mirabilis (Lour.) Druce. is a pitcher plant species at a higher risk of extinction mainly due to overexploitation. Previous investigations have shown that in vitro micropropagation can be used as an approach for ex-situ conservation of N. mirabilis. Therefore, this study aimed to assess the new shoot formation of N. mirabilis under in vitro conditions stimulated with the application of flurprimidol and GA3. The three concentrations of flurprimidol and GA3 used as treatments were arranged factorially in a Randomized Complete Block Design (RCBD), with internodes 2, 3, 4, and 5 serving as blocks. Based on the results, F1G0 (flurprimidol of 1 mgL-1 without GA3) had the highest shoot formation, which was not accompanied by sufficiently high contents of chlorophyll, leading to improper shoot development. Despite the smaller number of newly formed shoots in F2G2 (flurprimidol of 2 mgL-1 and GA3 of 2 mgL-1), significantly higher chlorophyll contents were observed, enabling better development of shoot. Leaf length and shoot diameter also showed similar results under F2G2, indicating that higher concentrations of exogenous GA3 were necessary for better shoot development. This indicated that appropriate concentrations of both plant growth regulators should be applied for micropropagation of N. mirabilis in support of ex-situ conservation.

In Vitro Shoot Induction of Musa acuminata cv. Mas Kirana

Abstract: The availability of �mother plants� used for source of explants is one of the most important limitations for the development of in vitro culture in new banana cultivar�s. To increase produce large quantities of uniform and healthy seedlings, induction of multiplication has been carried out on Musa acuminata cv. Mas Kirana. Plant regeneration were obtained by culturing sucker on MS medium supplemented with PGRs BAP and NAA (1 mg/l + 0.5 mg/l, 2 mg/l + 0.5 mg/l, and 3 mg/l + 0.5 mg/l) and TDZ (0.25 mg/l, 0.5 mg/l, and 0.75 mg/l). The highest shoot formation was found in 0.25 mg/l TDZ with average shoots of 13.67 � 3.16 and primary shoot height is 20 cm. TDZ induction tends to form somatic embryos, while induction of BAP and NAA leads to organogenesis. The rate of contaminants occurrence from bacteria is 87.50% and 12.50% from fungus. In histological observation, TDZ, BAP, and NAA affect the development of many new meristematic zones seen in the scalps.

Young capitulum as important explant in in vitro mass propagation of gerbera (Gerbera jamesonii)

A new route of in vitro propagation of gerbera selected clones was successfully established using young capitula in tight buds and buds that were started to unfold stage as explant source. The one-fourth pieces of young capitula of tight flower stage and half-strength MS medium containing 0.25 mg/l BAP was the suitable for initiation and produced higher number of shoots per explant up to 3.8 shoots. The results were improved by culturing the one-fourth piece of 01.092 capitulums on MS medium fortified by 0.2 mg/l BAP and 0.02 mg/l NAA producing the highest shoot formation up to 8.5 shoots per explant with 28.7 leaves per explant and 2.1 cm leaf length. High multiple shoots were determined in third to fourth subculture periods and reduced thereafter with high multiplication rate noted on 01.092 clone. Shoots were easily rooted on half-strength MS medium supplemented with 2 g/l activated charcoal. Plantlets were transferred to ex vitro condition with 96.4% survivability of 03.045 clone using Cycas rumphii bulk and cocopeat (1:1, v/v) under spraying 1 g/l Growmore (32N:10P:10K) solution once week periodically. The route has high potential applied in qualified plantlet production for other Gerbera’s due to high shoots produced up to 35 shoots per whole young capitulum used.

Generation of Virus Free Potato Plantlets through Meristem Culture and Their Field Evaluation

Different aspects of micropropagation through meristem culture for the production of virus indexed source plants, in vitro tuberization and field evaluation of the in vitro regenerated plants were studied on four commercial cultivars of potato (Solanum tuberosum L.) viz., Diamant, Cardinal, Shilbilati and Lalpakri. The investigation was conducted at Rajshahi, Bangladesh from December 2010 to March 2012 to produce virus-free potato plantlets through meristem culture, shoot multiplications with root induction as well as their acclimatization and evaluation of morphological characters and tuber yield under field condition. Shoot tips of 25 - 30 day old field-grown plants of above mentioned four cultivars were used for meristem isolation. After isolation, meristems of these varieties of potato were cultured on “M” shaped filter paper bridge in Murashige and Skoog (MS) liquid medium. Four different treatments of media formulations viz. 0.1 mg/L KIN + 0.1 mg/L GA3, 0.1 mg/L KIN + 0.5 mg/L GA3, 0.5 mg/L KIN + 0.1 mg/L GA3 and 0.5 mg/L KIN + 0.5 mg/L GA3 were used as plant growth regulators. From these formulations MS + 0.1 mg/L KIN + 0.5 mg/L GA3 was found to be the best for the primary establishment of meristem culture. The primarily established meristems were subcultured on to MS semisolid basal medium supplemented with four different treatment combinations of hormones viz. 0.5 mg/L BA + 1.0 mg/L IBA; 0.1 mg/L KIN + 0.1 mg/L GA3; 0.5 mg/L BA + 0.5 mg/L GA3 and 0.5 mg/L KIN + 0.5 mg/L GA3 were used to identify the suitable media compositions for shoot proliferation. Results showed that out of these four media treatments the formulation 0.5 mg/L BA + 0.5 mg/L GA3 was found to be the best suitable for shoot generation. Among the four cultivars of potato higher frequency of shoot proliferation (number of shoots/explant and longest shoot length) was observed in Diamant, though the highest shoot formation (76%) was recorded in Cardinal. Virus free in vitro grown potato plantlets were obtained through DAS-ELISA test and used substantially for micro-propagation. After gradual acclimatization of rooted plantlets of four potato cultivars, they were transferred into the field for cultivation and established successfully. It was observed from the field study of in vitro meristem-derived plantlets that there were no virus-affected plants. The virus-free exotic varieties were much superior in all vegetative attributes and yield compared to those of indigenous varieties with producing potato plants of normal height. In contrast, the indigenous varieties took a longer time to tuber initiation and maturity, lower plant height and number of leaves per plant, a higher number of tubers but a lower amount of tuber weight per plant, and poorer tuber grade than the exotic varieties. However, the variety Cardinal exposed the best performances in the context of survival percentage of plantlets (90%), days to tuber initiation (DTI), a number of leaves per plant (NL), tuber weight per plant (343.40%) and the percentage of rich tuber grade.

In vitro clonal propagation, organogenesis and somatic embryogenesis in Bacopa monnieri (L.) Wettst

Bacopa monnieri (L.) Wettst is a well-known medicinal herb in the Ayurveda. It is also used as laxative and curative for ulcers, inflammation, anaemia, scabies, leucoderma, asthma and epilepsy, enlargement of spleen, leprosy and others. In vitro propagation and regeneration through somatic embryogenesis of B. monnieri has played an important role in the production of healthy, disease-free plants with desirable traits. In B. monnieri, there are few reports which indicate rapid regeneration and somatic embryogenesis. For in vitro clonal propagation, the highest shoot formation was obtained when BAP 2 mg/ l used. The best response for rooting was obtained in IAA 1.0 mg/ l. The recorded survival rate of the plants was 70%. Plants were without any detectable phenotypic variations. Cytological study indicated that the chromosome number remain same (2n= 64) in in vitro and in vivo roots. A rapid, simple and efficient protocol for plantlet regeneration was achieved through embryogenic callus from leaf explants of B. monnieri. Callus induction and embryogenesis were significantly affected by presence/absence and type and concentration of growth regulators. Best organogenic callus induction was obtained in MS medium supplemented with BAP 5mg/ l. For induction of somatic embryogenesis, auxin (2, 4-D 1 mg/ l) was used in the culture medium subsequently in basal media for embryo maturation. Kn 0.2 mg/ l was the best for production of plantlet from embryo. Thus, this can be an easiest protocol for stable clonal propagation and plant regeneration through somatic embryogenesis in B. monnieri. The protocol used here for propagation and regeneration is much easier, low cost and reliable.

Sodium nitroprusside enhances callus induction and shoot regeneration in high value medicinal plant Canscora diffusa

The present investigation was carried out to demonstrate the plant morphogenetic potential of sodium nitroprusside (SNP) in a commercially important medicinal plant Canscora diffusa. Leaf and nodal explants were used and highest callusing frequency (97.18%) was recorded for leaf explants supplemented with 1.0 mg/L NAA +2.0 mg/L 2ip + 15 µM SNP. SNP enhanced multiple shoot formation in both nodal and leaf explants derived callus considerably in the media supplemented with 1.0 mg/L NAA + 15 µM SNP and 0.5 mg/L BAP + 15 µM SNP (98.32 and 96.12%) respectively. The root induction also drastically increased with the supplementation of SNP (10 µM) in combination with 1.0 mg/L IBA. Our results proved that SNP with other growth hormones acts synergistically to enhance the in vitro responses including the callus, shoot, and root induction. This optimized tissue culture system will be very useful for the mass propagation of C. diffusa for both commercial and conservation aspects. First report using sodium nitroprusside to enhance in vitro propogation of Canscora diffusa presented. Synergestic action of various growth regulators on SNP supplementation reported. Leaf and nodal segments used as explants produced better callusing and higher shoot formation with SNP treatments.

Genetic differentiation and host preference reveal non‐exclusive host races in the generalist parasitic weed Phelipanche ramosa

SummaryWe developed 20 microsatellite markers to genotype over 100 populations of the parasitic weed Phelipanche ramosa, which covers a wide host crop and geographic range. A representative core collection of 15 populations was also used in cross‐infestation assays to study host preference during germination, attachment and shoot formation. We observed low genetic differentiation within most of the populations, but high genetic differentiation between populations partitioned into 3 genetic groups with different host preferences and geographic distributions. Genetic group 1 is detected exclusively in western France and on various host crops, notably winter oilseed rape (WOSR) and not hemp. Cross‐infection assays confirmed its incompatibility with hemp and showed its preference for WOSR and tobacco in terms of germination and attachment success. The group 2 populations share a large geographic distribution in France and Europe, low germination success with WOSR and high germination success, attachment success and shoot formation with hemp, tobacco or tomato. The subclades 2a and 2b include most of the French populations in hemp crops in eastern France and in tobacco fields in several European countries respectively. The genetic analyses revealed the potential of the three groups to increase their geographic range in the future. Intermediate genetic groups showed higher intrapopulation diversity and represent potential stocks for new host race emergence. Those findings argue in favour of the existence of host races in P. ramosa and should be considered for appropriate management strategies, notably in breeding programmes for resistance against this parasitic weed.

Evaluation of the antioxidant potential of in vitro propagated hyssop (Hyssopus officinalis L.) with different plant growth regulators

An efficient method for the micro propagation of hyssop (Hyssopus officinalis L.) has been developed. The plants were cultured on Murashige and Skoog's medium supplemented with 6-benzyl-aminopurine, thidiazuron, zeatin and indole-3butyric acid after four weeks of culture. Maximum numbers of shoots, shoot length, fresh weight and dry weight were established at 1.0 mg/L 6-benzyl-aminopurine and 0.1 mg/L indole-3-butyric acid. For induction of root, uniform micro shoots were excised and transferred to the rooting medium (half strength Murashige and Skoog medium macro and microelements) supplemented with 0.1 mg/L indole-3-butyric acid and 20 g/L sucrose. Indole-3-butyric acid increased culture rooting, number of roots and root length more efficiently at 0.1 mg/L after four weeks of culture. The multiple plants were successfully ex vitro adapted with 90% survival. The described protocol allows the establishment of numerous micro propagated plants of H. officinalis. The used growth regulators for hyssop micro propagation influenced plant antioxidant system. Antioxidant defence of micropropagated H. officinalis determined by the activities of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and guaiacol peroxidase) resulted in higher shoot formation and increasing of shoot number per explant.

Effect of Hormone Types and Concentrations on In Vitro Multiplication and Growth of Pineapple (Ananas Comosus (L.) Merr.) Cv Moris on Liquid MS Medium

The effect of two cytokinins, 6-benzyleaminopurine (BAP) and kinetin (KN) and two auxins, naphthalene acetic acid (NAA) and indole acetic acid (IAA) each applied at 10 concentrations with an increment of 0.5 mg/l in the in vitro shoot formation of Moris pineapple was evaluated in static liquid MS medium. The highest shoot formation (9 shoots per explant) was obtained in medium enriched with NAA but at high concentration (4.5 mg/l). The second best was 8 shoots per explant obtained in medium enriched with BAP at 2.0 mg/l. Out of 10 concentrations, NAA was better than BAP at the highest 5 and less at lowest 5 concentrations and at all concentrations both hormones resulted in production of more shoots per explant than hormone free medium. Except at two concentrations, NAA and BAP were better than KN. Either one of these three hormones, BAP, NAA, KN could be claimed, depending on the tested range of concentrations, better than the others for in vitro shoot formation of Moris pineapple. All of the IAA concentrations, on the other hand, failed to produce more shoots than hormone free medium. But, the longest shoot (56 mm) obtained in medium enriched with IAA at 2.5 mg/l and the shortest shoots (6 mm) on medium enriched with KN at 4.0 mg/l. Seven of the IAA concentrations resulted in shoots longer than hormone free medium (27 mm) while the shoots length on the BAP, NAA and KN contained media was two times shorter than hormone free medium. BAP at 2.0 mg/l was the best treatment for multiplication and IAA at 2.5 mg/l was the best for elongation of Moris pineapple.

Effect of Light Quality, Sucrose and Trehalose on In Vitro Organogenesis of Cymbidium devonianum (Lindl.)

The present study investigated the effect of sucrose, trehalose and combination of sucrose and trehalose with modified MS medium on in vitro regulation of protocorm-like bodies (PLBs) of Cymbidium devonianum under different quality of lights (white fluorescent tube, green, red and blue LED). As a result of this study, new PLB and shoots were successfully regenerated on modified MS medium under different quality of lights. The highest PLB formation rate (100%) and the highest shoot formation rate (85%) were observed amongst explants cultured on medium supplemented with 10 g/l sucrose + 10 g/l trehalose under green LED. The maximum fresh weight of PLBs, the highest average number of PLBs and shoots were recorded on medium containing 10 g/l sucrose + 10 g/l trehalose under green LED. For plant tissue culture, sucrose is considered an indisputably important carbon and energy source and biosynthesis of trehalose is similar to that of sucrose. The hereby study concluded that the contribution of LED lights, sucrose and trehalose (combined) can induce PLB and shoot formation of Cymbidium devonianum tissue culture without the use of any other plant growth regulator, whereas the green light showed the best formation rate compare with the other studied qualities of lights.

ОТДАЛЕННАЯ ГИБРИДИЗАЦИЯ ВИДОВ РОДА ALLIUM L.

The basic problem of breeding of onions, including development of varieties and hybrids, characterized by high yield, early maturity, marketable product that are grown in different regions of the country is described in the article. The combination of resistance to pests and diseases in the same variety/hybrid is the most problematic. Interspecific hybridization of onions is promising, as a result of which, along with resistance to diseases, provided early spring regrowth of plants, their high shoot formation, the long period of return of greenery as well as a high solids content, vitamins, and volatile production in the bulbs and aboveground mass. Perennial onions are donors of cold and frost resistance. VNIISSOK scientists, Omsk Agricultural Institute and other institutions in the country set up a number of interspecific hybrids with wild species of onions, which are of undoubted interest for practical use. However, a significant portion of perennial species is not compatible with cultivated ones. The main reason is the different number of chromosomes in parents, and hence irregularities in meiosis and sterile progeny. To overcome the sterility of hybrids there are effective methods of modern biotechnology, including the embryo culture in vitro and polyploidization. The initial material for research is the collection of VIR, with more than 3,000 samples and diverse breeding material obtained by breeders of our country.

Optimization of Regeneration Conditions and In Vitro Propagation of Sideritis Stricta Boiss & Heldr

In this study the micropropagation of endemic species Sideritis stricta was investigated. Leaf segments and shoot explants (hypocotyl, single node and shoot tips) taken from in vitro growing plantlets and cultured on MS and B5 media containing different growth regulators combinations BAP (0.0, 1.0, 2.0 and 3.0mg/l) and NAA (0.0, 0.1 and 0.5mg/l). MS and B5 media supplemented with BAP (1.0, 2.0 and 3.0mg/l) and NAA (0.1mg/l) combinations or only BAP and kinetin (2.0 and 3.0mg/l) were used at the subculture experiments of shoots and MS and B5 media supplemented with different concentrations of IBA (0.0, 1.5, 3.0, 4.5 and 10.mg/l) were used at the rooting experiments. S. stricta seeds germinated at the rate of 100% when the seed coat was removed and endoperm with embryo part cultured on B5 medium. The single node explants taken from in vitro germinated and grown 30–40 days plantlets on B5 medium have been determined as the most successful explant at all used hormone combinations. B5 medium supplemented with 1.0mg/l BAP+0.1mg/l NAA and 2.0mg/l BAP+0.5mg/l NAA was determined as the most effective medium on shoot formation. At the first and second subculture, the highest shoot formation was maintained on medium supplemented with 1.0mg/l BAP+0.1mg/l NAA and the number of shoots per explant were 4 and 2.11, respectively. The highest multiplication rate has been determined as 33.76 at the end of second subculture. The best rooting was achieved on B5 medium supplemented with 4.5mg/l IBA. The rooted shoots were successfully acclimatized to outdoor conditions and survival rate was determined as 90%.

Leaf-derived organogenesis in vitro for mass propagation of lisianthus (Eustoma grandiflorum (Raf.) Shinn

Lisianthus (Eustoma grandiflorum (Raf.) Shinn) is an important ornamental commodity in South-East Asia. However, mass propagation of the plant at a commercial scale to satisfy market demands is faced by limited availability of high quality and uniform seedlings as planting material. Using different regeneration media and leaf explants for callus induction, regeneration, proliferation, root formation and acclimatization were studied. High callus induction and adventitious shoot formation were possible from leaf explants of E. grandiflorum ‘White Lavender’ cultured on Murashige and Skoog (MS) medium supplemented with 3.0 mg/l thidiazuron (TDZ) and 0.3 mg/l α-naphthalene acetic acid (NAA), but high quality shoots (8.0) was established on MS medium containing 0.5 mg/l N6-benzyladenine (BA) and 0.002 mg/l NAA. In the same medium, adventitious shoots could be multiplied up to the fourth subculture at a rate of 1.74 which decreased to a 1.57 multiplication rate in subsequent subcultures. Shoots rooted easily on MS medium containing 0.1 mg/l BA and 0.02 mg/l NAA with 3.9 roots per shoot. The plantlets, which were successfully acclimatized in a mixture of burned-rice husk and organic manure (1:1, v/v) with 90% survival, grew well after repotting.

In vitro propagation, genetic and phytochemical assessment of Thymus persicus — a medicinally important source of pentacyclic triterpenoids

AbstractThymus persicus (Ronniger ex Rech. f.) Jalas is a valuable and endangered natural source of antitumor pentacyclic triterpenoids, i.e., betulinic acid, oleanolic acid and ursolic acid, which grows in northwest Iran. As the plant has a low propagation rate in nature, a suitable method for in vitro-propagation is needed. With the aim of identifying a suitable system for regenerating T. persicus via direct organogenesis, Murashige & Skoog (MS) medium supplemented with different plant growth regulators (PGRs) was tested. In vitro-grown shoot tips were exposed to the cytokinins 6-benzylaminopurine (BAP), kinetin (KN), and thidiazuron (TDZ), alone or in combination with the auxins 1-naphthalene-acetic acid (NAA), 2,4-dichlorophenoxyacetic (2,4-D), indole-3-butyric acid (IBA) and indole-3-acetic acid (IAA). The highest shoot formation (7.1 ± 0.9) was obtained with a medium fortified with 8.9 μM BAP plus 2.7 μM NAA. Regenerated shoots were easily rooted on the different tested media, with the most abundant (16.6 ± 1.4) and strongest roots obtained on half-strength MS medium containing 2.5 μM IBA. The rooted plantlets were successfully acclimatized (76.6%) in a greenhouse before transference to natural conditions. Homogeneity and phytochemical productivity of the in vitro regenerated plantlets were confirmed by random amplified polymorphic DNA (RAPD) profiles and high performance liquid chromatography (HPLC), respectively.

Multiplicação in vitro de segmentos apicais caulinares de segurelha (Satureja hortensis L.)

O presente estudo teve por objetivo avaliar o efeito de BAP, na presença e ausência de ANA, sobre a multiplicação in vitro de segmentos apicais caulinares de Satureja hortensis. Os explantes foram isolados de plântulas germinadas in vitro e cultivados em meio nutritivo MS. O delineamento experimental utilizado foi o inteiramente casualizado, em esquema fatorial 2x5, correspondendo às concentrações de ANA (0 e 1 µM) e de BAP (0; 5; 10; 15 e 20 µM), com seis repetições, cada uma composta por três explantes. Para a porcentagem de explantes com brotações houve efeito significativo para o fator BAP, aumentando à medida que cresce a concentração da citocinina. A variável "número de brotos por explante" apresentou interação entre os fatores, havendo a maior formação de brotos na presença de ANA na faixa de 10 - 15 µM de BAP. Na presença da auxina, o maior valor ocorreu com 15 µM de BAP tendendo a diminuir independente da presença de ANA. O enraizamento dos segmentos apicais foi maior na presença de ANA e ausência de BAP, diminuindo com o aumento da citocinina. O número de folhas foi influenciado pela maior concentração de BAP sendo que a 15 µM foi observado o maior número, tendendo à queda com aumento da concentração. A concentração de 15 µM de BAP, independente de ANA, proporcionou os melhores resultados na multiplicação da espécie produzindo aumento de brotações e número de folhas, à exceção do enraizamento que foi influenciado pela auxina.

Multiple nitrogen and phosphorus deficiency in Zantedeschia

Multiple nutritional deficiencies are considered one of several factors that can induce doubt in the diagnosis based only in visual symptoms, because it makes identification more difficult. The aim of this work was to evaluate the development of Zantedeschia and the morphological changes resulting from nutritional disorders caused by multiple and simple nitrogen and phosphorus deficiency in plants grown in nutrient solution. Zantedeschia plants were grown for a period of eight months in a complete Hoagland and Arnon (1950) solution, with nitrogen (-N) omission, with phosphorus (-P) omission, with nitrogen and phosphorus (-NP) omission, and also nutrient solution with N and P at concentrations of 25, 50 and 75%, totalizing 7 treatments, with 4 replicates in a completely randomized experimental design. At the end of the experimental period, plant height, number of emitted leaves, leaf size, number and mineral composition of shoots were assessed. The omission of nutrients both in simple and multiple forms affected plant development. The highest shoot formation occurred in plants grown in solution and with 50% of the concentration of NP. The mineral composition of macronutrients present in leaves and shoots of plants was influenced by multiple deficiencies of N and P.

The tomato (Solanum lycopersicum cv. Micro-Tom) natural genetic variation Rg1 and the DELLA mutant procera control the competence necessary to form adventitious roots and shoots.

Despite the wide use of plant regeneration for biotechnological purposes, the signals that allow cells to become competent to assume different fates remain largely unknown. Here, it is demonstrated that the Regeneration1 (Rg1) allele, a natural genetic variation from the tomato wild relative Solanum peruvianum, increases the capacity to form both roots and shoots in vitro; and that the gibberellin constitutive mutant procera (pro) presented the opposite phenotype, reducing organogenesis on either root-inducing medium (RIM) or shoot-inducing medium (SIM). Mutants showing alterations in the formation of specific organs in vitro were the auxin low-sensitivity diageotropica (dgt), the lateral suppresser (ls), and the KNOX-overexpressing Mouse ears (Me). dgt failed to form roots on RIM, Me increased shoot formation on SIM, and the high capacity for in vitro shoot formation of ls contrasted with its recalcitrance to form axillary meristems. Interestingly, Rg1 rescued the in vitro organ formation capacity in proRg1 and dgtRg1 double mutants and the ex vitro low lateral shoot formation in pro and ls. Such epistatic interactions were also confirmed in gene expression and histological analyses conducted in the single and double mutants. Although Me phenocopied the high shoot formation of Rg1 on SIM, it failed to increase rooting on RIM and to rescue the non-branching phenotype of ls. Taken together, these results suggest REGENERATION1 and the DELLA mutant PROCERA as controlling a common competence to assume distinct cell fates, rather than the specific induction of adventitious roots or shoots, which is controlled by DIAGEOTROPICA and MOUSE EARS, respectively.

식물생장조절제 및 광원처리에 따른 헛개나무 줄기와 경정유래 신초의 기내증식

This study was conducted to examine effects of plant growth regulators and light resources on the formation of multiple shoot and plant regeneration of Hovenia dulcis var. koreana Nakai. Stem and shoot tip were cultured on MS medium or WPM supplemented with various plant growth regulators. At the single treatment, the highest shoot formation was obtained when stem explants were cultured on WPM supplemented with kinetin 1.0㎎ · L^-1. MS medium containing NAA 0.1 and TDZ 0.1 ㎎·L^-1 gave the best results for shoot induction rate and shoot growth in combination treatments. Of the BAP and kinetin tested, BAP 0.5 ㎎·L^-1 on WPM was found to be more effective for shoot growth from shoot tip. Under white fluorescent light treatment, shoot growth was much higher than blue, red LED treatments. Root induction from in vitro growth of plantlet was the best on WPM supplemented with 1.0㎎ · L^-1 IBA. The results suggest that selection of plant growth regulators and light resources could be important factor to achieve an efficient in vitro growth.

Recalcitrant effects associated with the development of basal callus-like tissue on caulogenesis and rhizogenesis in Sclerocarya birrea

In the micropropagation of woody plant species, adventitious root and shoot formation remain some of the major bottlenecks due to their recalcitrance to in vitro manipulation. Some plant growth regulators may ameliorate these recalcitrant effects and improve in vitro caulogenic and rhizogenic processes. Shoot induction on shoot meristems, hypocotyls and epicotyls was evaluated using equimolar concentrations of benzyladenine (BA), meta-topolin (mT), meta-topolin riboside (mTR), and meta-methoxytopolin riboside (MemTR). Three auxins, indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and α-naphthalene acetic acid (NAA) were used in the induction of adventitious roots. Moderately high shoot formation (62.7%) was achieved at a concentration of 8.0 μM mT after 8 weeks in culture. The highest number of adventitious shoots per explant (2.4 ± 0.3) and the longest shoots (23.5 ± 3.16 mm) were recorded on 8.0 μM mT, though not significantly different from BA treatments. Most shoots progressively produced brown basal callus, which is a potential sink for cytokinin conjugates that are inhibitory to further proliferation of adventitious shoots. Good adventitious shoot formation occurred in 55% of hypocotyl explants on 8.0 μM mT. The highest rooting (91.6%) was achieved with IBA-treated shoots at a concentration of 4.0 μM. The use of mT and IBA provide an efficient micropropagation method for S. birrea, though further research is required especially in overcoming ex vitro plantlet survival challenges.