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Euryodendron excelsum H. T. Chang, a critically endangered species endemic to China, is a source of valuable material for the furniture and construction industries. However, this species has some challenges associated with rooting during in vitro propagation that have yet to be resolved. In this study, we optimized rooting and conducted a transcriptomic analysis to appreciate its molecular mechanism, thereby promoting the practical application of in vitro propagation of E. excelsum, and providing technical support for the ecological protection of this rare and endangered species. Results showed that ex vitro rooting performed the highest rooting percentage with 98.33% at 25 d. During ex vitro rooting, there was a wide fluctuation of endogenous levels of indole-3-acetic acid (IAA) and hydrogen peroxide (H2O2) at the stage of root primordia formation. Transcriptome analysis revealed multiple differentially expressed genes (DEGs) involved in AR development. DEGs involved in plant hormone signal transduction, such as genes encoding auxin-induced protein, auxin-responsive protein, and IAA-amido synthetase Gretchen Hagen3, and in response to H2O2, oxidative stress, abiotic and biotic stimuli were significantly up- or down-regulated by ex vitro treatment with 1 mM indole-3-butyric acid (IBA). Our results indicate that ex vitro rooting is an effective method to induce AR from E. excelsum plantlets during micropropagation. DEGs involved in the plant hormone signal transduction pathway played a crucial role in AR formation. H2O2, produced by environmental stimulation, might be related to AR induction as a result of the synergistic action with IBA, ultimately regulating the level of endogenous IAA.

The primary objective of this work was to generate species-specific information about root architectural adaptation to variation in boron (B) availability at the onset of storage root formation among three sweetpotato [Ipomoea batatas (L.) Lam] cultivars (Beauregard = BX; Murasaki = MU; Okinawa = OK). Three B levels were used: 0B (B was omitted in the nutrient solution, substrate B = 0.1 mg·kg−1), 1XB (sufficient B; 0.5 mg·kg−1), and 2XB (high B; 1 mg·kg−1). The check cultivar BX showed evidence of storage root formation at 15 days in 0B and 1XB, whereas cultivars MU and OK failed to show evidence of root swelling. The 1XB and 2XB levels were associated with 736% and 2269% increase in leaf tissue B in BX, respectively, relative to plants grown in 0B. Similar magnitudes of increase were observed in MU and OK cultivars. There were no differences in adventitious root (AR) count within cultivars but OK showed 25% fewer AR numbers relative to BX across all B levels. 0B was associated with 20% and 48% reduction in main root length in BX and OK, respectively, relative to plants grown in 1XB and 2XB. 2XB was associated with a 10% increase in main root length in MU relative to plants grown in 0B and 1XB. 0B was associated with reduced lateral root length in all cultivars but the magnitude of responses varied with cultivars. These data corroborate findings in model systems and well-studied crop species that B deficiency is associated with reduced root growth. These data can be used to further understand the role of cultivar-specific responses to variation in B availability in sweetpotato.

In legumes, waterlogging is a major detrimental factor leading to huge yield losses. Generally, legumes lack tolerance to submergence, and conventional breeding to develop tolerant varieties are limited due to the lack of tolerant germplasm and potential target genes. Moreover, our understanding of the various signalling cascades, their interactions and key pathways induced during waterlogging is limited. Here, we focus on the role of two important plant signalling molecules, viz. hydrogen sulphide (H2 S) and nitric oxide (NO), during waterlogging stress in legumes. Plants and soil microbes produce these signalling molecules both endogenously and exogenously under various stresses, including waterlogging. NO and H2 S are known to regulate key physiological pathways, such as stomatal closure, leaf senescence and regulation of numerous stress signalling pathways, while NO plays a pivotal role in adventitious root formation during waterlogging. The crosstalk between H2 S and NO is synergistic because of the resemblance of their physiological effects and proteomic functions, which mainly operate through cysteine-dependent post-translational modifications via S-nitrosation and persulfidation. Such knowledge has provided novel platforms for researchers to unravel the complexity associated with H2 S-NO signalling and interactions with plant stress hormones. This review provides an overall summary on H2 S and NO, including biosynthesis, biological importance, crosstalk, transporter regulation as well as understanding their role during waterlogging using 'multi-omics' approach. Understanding H2 S and NO signalling will help in deciphering the metabolic interactions and identifying key regulatory genes that could be used for developing waterlogging tolerance in legumes.

Medicinal plants of Jordan are under threat due to several factors of habitat perturbation. Some of these factors include ruinous, over-harvesting, climate change, competition and invasion. In this study simple we employed a reliable method for micropropagation and assessment of antimicrobial activity of some important medicinal plants of Jordan. Seeds were surface sterilized and germinated on agar water media, and then shoots were cultured on Murashige and Skoog (MS) medium with the addition of 3% sucrose. To generate enough plant material, microshoots were transferred after fourteen days onto hormone free MS medium. Among all studied plants we found that Achellia millefolium and Moring perigrina plants were successful multiply in vitro containing different 6-benzyl amino purine (BA). For potential antimicrobial activity ex vitro (field leaf plants) and in vitro (plantlet) extracts were evaluated against some bacteria strain using ethanolic extracts. Both ex vitro and in vitro plants extract showed antimicrobial activity against the microorganism tested. The results from the study suggest that these two plants showed good antimicrobial activity against the different tested bacteria.

Kendala utama dalam budidaya tanaman manggis adalah lambatnya pertumbuhan fase seedling karena minimnya akar yang terbentuk. Untuk mengatasi masalah tersebut salah satu upaya yang dapat dilakukan yaitu dengan pemberian zat pengatur tumbuh pemacu pertumbuhan akar, salah satunya menggunakan ZPT alami dari ekstrak bawang merah dan tomat. Penelitian ini bertujuan untuk mengetahui pengaruh konsentrasi ekstrak bawang merah dan ekstrak tomat yang terbaik pada pertumbuhan seedling manggis. Kedua bahan ini dipilih sebagai sumber zpt karena bawang merah sering digunakan untuk pemacuan akar pada setek dan tomat sering digunakan sebagai bahan addenda pada media kultur jaringan. Penelitian ini disusun secara faktorial (3×2) menggunakan rancangan acak kelompok (RAK) dengan perlakuan ekstrak bawang merah konsentrasi 0 g L-1, 400 g L-1, dan 800 g L-1, dan ekstrak tomat konsentrasi 0 g L-1 dan 100 g L-1 yang diulang sebanyak tiga kali. Data dianalisis dengan sidik ragam dan uji lanjut BNT pada taraf 5%. Hasil penelitian menunjukkan bahwa pemberian ekstrak bawang merah konsentrasi 400 g L-1 dapat meningkatkan diameter batang, bobot segar tanaman, dan menunjukkan kecenderungan perlakuan yang terbaik pada jumlah akar sekunder seedling manggis. Pemberian ekstrak tomat 100 g L-1 dapat meningkatkan bobot segar tanaman dan terjadi interaksi antara pemberian ekstrak bawang merah dengan ekstrak tomat pada luas daun. Pada perlakuan ekstrak bawang merah konsentrasi 400 g L-1 tanpa penambahan ekstrak tomat atau perlakuan ekstrak tomat 100 g L-1 tanpa ekstrak bawang merah menghasilkan luas daun yang lebih tinggi dibandingkan dengan penggunaan kedua campuran ekstrak tersebut.

Sedum aizoon L. is a medicinal plant that contains various flavonoids and phenolic acids, and plays positive roles in lowering blood pressure, hemostasis, anti-bacterial and anti-inflammatory. However, the clinical application of Sedum aizoon L. is limited because of its low yield in natural state. Here, we aim to explore the application of adventitious root culture technology in Sedum aizoon L., further to improve the yield of Sedum aizoon L. and the production of secondary metabolites. We found that the callus of Sedum aizoon L. could be induced in MS medium containing 2.0 mg L−1 2,4-D and 0.5 mg L−1 BA. Then, the adventitious roots were obtained in Sedum aizoon L. with maximum induction rate (98.32%) when the callus were cultured in a stratified combination MS medium supplemented with 4.0 mg L−1 IBA, 1.0 mg L−1 KT, 1.0 mg·L−1 NAA and 60 mmol L−1 NO3−/NH4+ (5:1 ratio). Furthermore, the production of flavonoids in adventitious roots of S. aizoon L. (16.32±0.51 mg·g−1 DW) was obviously higher than those in the callus (3.66±0.65 mg g−1 DW). In conclusion, we determined that adventitious roots culture might be an effective alternative in improving the potential application of Sedum aizoon L..

In the garden of Omsk Agrarian Scientific Center, located in the southern forest-steppe of Omsk region in 2018-2020 research has been carried out with the aim of studying the features of the influence of various stimulants of root formation during the propagation of clonal pear rootstocks by green and lignified cuttings. The soil is meadow-chernozemic medium loamy with a pronounced sandy fraction, the reaction of the soil solution is close to neutral. The object of research is clonal pear stocks PG 2, PG 12, PG 17-16. Rooting of green and lignified cuttings was carried out in a greenhouse with a film coating with an artificial fogging installation. The substrate is a mixture of sand and peat (1 to 1). Planting scheme of cuttings 5×5 cm, in four replicates (50 pcs.), Placement is randomized. Kornevin (powdering of sections), and Ribav-extra, control – water (duration of exposure - 16 h) were used as stimulants of root formation during green cuttings. When propagating by lignified cuttings, cornevin (0,1%) and ribav-extra (0,01%) were used; water was used as control (exposure duration - 16 h). Clonal pear rootstocks tolerated the winter conditions of the study years relatively favorably. The exception was winter 2019-2020, the total degree of freezing was 1 point in the PG 2 and PG 17-16 rootstocks, and 5 points in the PG 12 rootstock (90% plant loss). The beginning of the growing season in 2018 was marked on May 22-23, in 2019 - May 5-6, in 2020 - April 18-19. In 2018-2019, green cuttings were carried out on June 20, in 2020 - on June 10. Earlier terms of cuttings in 2020 are explained by the rapid regrowth and lignification of the shoots (hot weather and lack of precipitation in the first months of the growing season). In the control, massive root formation was noted after 6 weeks. The treatment of cuttings with growth stimulants promoted the acceleration of root formation, which was observed after 4 ... 5 weeks. On average, over the years of research, rooting rate when using Kornevin, in comparison with control, increased by 13 ... 18%, Ribav -extra - by 10 ... 13%. The rootstock PG 12 is characterized by a higher rooting Kornevin of green cuttings (51.5 ... 56.5%) than that of PG 2 (47.7 ... 49%) and PG 17-16 (41.7 ... 44.3%). Rooting rate when using Kornevin was 50%, Ribav - extra 47%. PG 12 is the only rootstock under study in which rooting of lignified cuttings is observed: in the control 24%, when using preparations 44.5 ... 52%

Pyrus communis is a difficult-to-root species, and its optimal rooting depends on applying an accurate concentration of various chemicals. Since statistical modeling can be applied to estimate the approximate range of factors needed for the success of in vitro plant propagation, we tried to optimize the rooting medium using response surface methodology. Therefore, sucrose and polyvinyl alcohol were selected as independent variables in the central composite design of response surface methodology with α = 1. Based on the pre-test, it was found that the independent variables for the root formation were 2 to 3% sucrose and 0.5 to 1.5 g L−1 polyvinyl alcohol in studied cultivars. The statistical analysis results showed that the quadratic models were significant, with high R2 values > 0.9 for rooting rate response. The optimized values for independent variables in rooting of the studied cultivars included 2% sucrose, 1.5 g L−1 polyvinyl alcohol in ‘Williams’; 2.85% sucrose, 1.47 g L−1 polyvinyl alcohol in ‘Natanzi’; and 3% sucrose, 0.99 g L−1 polyvinyl alcohol in ‘Ghosi’. A separate validation experiment detected that the experimental values of the studied responses are in close agreement with predicted values in all cultivars. For the first time, the methodology was developed using a central composite design to optimize the rooting in P. communis.

Adventitious roots (ARs) are an important root type for plants and display a high phenotypic plasticity in response to different environmental stimuli. Previous studies found that dark-light transition can trigger AR formation from the hypocotyl of etiolated Arabidopsis thaliana, which was used as a model for the identification of regulators of AR biogenesis. However, the central regulatory machinery for darkness-induced hypocotyl AR (HAR) remains elusive. Here, we report that photoreceptors suppress HAR biogenesis through regulating the molecular module essential for lateral roots. We found that hypocotyls embedded in soil or in continuous darkness are able to develop HARs, wherein photoreceptors act as negative regulators. Distinct from wound-induced ARs that require WOX11 and WOX12, darkness-induced HARs are fully dependent on ARF7, ARF19, WOX5/7, and LBD16. Further studies established that PHYB interacts with IAA14, ARF7, and ARF9. The interactions stabilize IAA14 and inhibit the transcriptional activities of ARF7 and ARF19 and thus suppress biogenesis of darkness-induced HARs. This finding not only revealed the central machinery controlling HAR biogenesis but also illustrated that AR formation could be initiated by multiple pathways.

The root system of potato is made up of adventitious roots (AR) that form at the base of a sprout once it emerges from the mother tuber. By definition, AR originate from dormant preformed meristems, or from cells neighboring vascular tissues in stems or leaves. This may occur as part of the developmental program of the plant (e.g., potato), or when replacing the embryonic primary roots in response to stress conditions, such as flooding, nutrient deprivation, or wounding. AR formation is studied mainly in cereals and model plants, and less is known about its developmental program in root and tuber crops. In this review, we summarize the recent data on AR development in potato and relate this knowledge to what is known from model plants. For example, AR formation following stem cutting in potato follows a pattern of initiation, expression, and emergence phases that are known for other plants and involves auxin, the master regulator of AR induction and development. Molecular regulation of AR formation and the effect of environmental stresses are discussed. Understanding the origin and nature of AR systems in important crops will contribute to increased production and improve global food security.

Direct plant regeneration from shoot tips and nodal explants of Wedelia calendulacea Less. was carried out in MS with different concentrations and combinations of BAP, Kn and NAA. Of the two explants nodal segments showed the best response towards the formation of multiple shoots in MS containing BAP (2.0 mg/l), Kn (1.0 mg/l) and NAA (0.5 mg/l). In this combination, the maximum number of shoots/explant obtained was 18.33 ± 0.72 from shoot tips and 26.64 ± 0.47 from nodal explants. Cent per cent root formation was obtained in MS with IBA (0.2 mg/l) within three weeks. The in vitro regenerated plantlets were successfully transplanted to soil for further growth and development. Plant Tissue Cult. & Biotech. 30(2): 277-283, 2020 (December)

Cotyledonary leaf and node of two varieties, namely red and yellow of Bell pepper (Capsicum annuum L.) were cultured in MS with different concentrations and combinations of plant growth regulators. The cotyledonary leaf was found to be most responsive towards multiple shoot regeneration. The leaf explants of red variety showed best result towards shoot regeneration in MS with BAP (8.0 mg/l), NAA (0.02 mg/l) and IAA (1.0 mg/l). Eighty per cent explants responded within 13 - 14 days, and the mean number of shoot per explant was was found to be 5.67. The cotyledonary leaf explants of yellow variety showed promising result when the cotyledonary leaf explant was cultured in MS with BAP (8.0 mg/l) and NAA (0.5 mg/l) being the mean number of shoot per explants 5.13 and 70% of them responded within 14 - 15 days. Maximum root induction was found in MS with IBA (0.5 mg/l) in both capsicum varieties. After successful root formation plantlets were transplanted and acclimatized to the soil. Plant Tissue Cult. & Biotech. 30(2): 267-275, 2020 (December)

The primary objective of this work was to generate species-specific information about root architectural responses to variations in inorganic phosphate (Pi) availability at the onset of storage root formation among six sweetpotato (Ipomoea batatas) cultivars. Three Pi levels were used: 0 (low Pi); 0.17 (medium Pi); and 0.34 (high Pi) g/pot triple super phosphate (0N–46P–0K). The check cultivar ‘Bayou Belle’ (BB) consistently showed evidence of storage root formation at 15 days in adventitious roots (ARs) grown across three Pi levels and two planting dates (PDs). Storage root formation was also detected in ‘Orleans’ (OR) and ‘Beauregard’ (BX), but it was less consistent relative to BB. In general, BB had the lowest adventitious root (AR) number relative to the other cultivars, but the magnitudes of difference varied with Pi availability and PD. With the first PD, BX had a 45% higher AR number compared with BB in low Pi conditions; however, there were no differences in the second PD. Within cultivars, BX and Okinawa grown in low Pi showed combined 17% and 24% reductions in primary root length (PRL) relative to roots grown in high Pi. BB had a higher lateral root number (LRN) and lateral root density (LRD) across Pi levels, corroborating prior data regarding the association of these root architectural attributes with the onset of storage root formation. The experimental data support the hypothesis regarding the existence of genetic variation for Pi efficiency in sweetpotato and that some well-documented Pi-efficient root traits like high LRN and LRD are indirectly selected for in-breeding programs that focus on early storage root formation and stable yields across environments.

The influences of indole-3-butyric acid (IBA) concentrations of 0–30 mg·g−1 on the success and speed of adventitious root development of Zamia furfuracea L.f. and Zamia integrifolia L.f. stem cuttings were determined. Root formation success for both species was greater than 95%. The IBA concentrations did not influence the speed of root development for Z. furfuracea, but the Z. integrifolia cuttings that received IBA concentration of 3 mg·g−1 generated adventitious roots more slowly than the cuttings in the control group. The ending dry weights of the stems, leaves, and roots were not influenced by IBA concentration for either species. Our results indicated that adventitious root formation on stem cuttings of these two Zamia species is successful without horticultural application of IBA. Additional IBA studies are needed on the other 300+ cycad species, especially those that are in a threatened category.

Investigation on in vitro multiple shoot regeneration in Bacopa monnieri (L.) Penn. using leaf and nodal explants was carried out on MS containing various concentrations and combinations of BAP, Kn, NAA and 2,4-D. Of the two explants, leaf showed the best response towards shoot regeneration and subsequent plant development on MS with 1.0 mg/l BAP and 0.25 mg/l Kn. In this combination, the mean number of shoots/explant was 10.6 ± 0.11 in leaf and 9.6 ± 0.29 in nodal explants. Maximum shoot length was recorded as 12.6 ± 0.21 and 11.20 ± 0.30 from leaf and nodal explants after six weeks of culture, respectively. Half strength of MS supplemented with 0.25 mg/l IBA was found to be the best medium for root formation. The in vitro regenerated plantlets were successfully transplanted in soil after acclimatization. Plant Tissue Cult. & Biotech. 30(1): 57-63, 2020 (June)

A major concern of sweetpotato producers is the potential negative effects from herbicide drift or sprayer contamination events when dicamba is applied to nearby dicamba-resistant crops. A field study was initiated in 2014 and repeated in 2015 to assess the effects of reduced rates of N,N-Bis-(3-aminopropyl)methylamine (BAPMA) or diglycloamine (DGA) salt of dicamba, glyphosate, or a combination of these individually in separate trials with glyphosate on sweetpotato. Reduced rates of 1/10, 1/100, 1/250, 1/500, 1/750, and 1/1,000 of the 1× use rate of each dicamba formulation at 0.56 kg ha−1, glyphosate at 1.12 kg ha−1, and a combination of the two at aforementioned rates were applied to ‘Beauregard’ sweetpotato at storage root formation (10 d after transplanting) in one trial and storage root development (30 d after transplanting) in a separate trial. Injury with each salt of dicamba (BAPMA or DGA) applied alone or with glyphosate was generally equal to or greater than glyphosate applied alone at equivalent rates, indicating that injury is most attributable to the dicamba in the combination. There was a quadratic increase in crop injury and a quadratic decrease in crop yield (with respect to most yield grades) observed with an increased herbicide rate of dicamba applied alone or in combination with glyphosate applied at storage root development. However, with a few exceptions, neither this relationship nor the significance of herbicide rate was observed on crop injury or sweetpotato yield when herbicide application occurred at the storage root formation stage. In general, crop injury and yield reduction were greatest at the highest rate (1/10×) of either salt of dicamba applied alone or in combination with glyphosate, although injury observed at lower rates would be cause for concern after initial observation by sweetpotato producers. However, in some cases yield reduction of No.1 and marketable grades was observed following 1/250×, 1/100×, or 1/10× application rates of dicamba alone or with glyphosate when applied at storage root development.

BackgroundAcer rubrum L. is a colorful ornamental tree with great economic value. Because this tree is difficult to root under natural conditions and the seedling survival rate is low, vegetative propagation methods are often used. Because the formation of adventitious roots (ARs) is essential for the survival of asexual propagation of A. rubrum, it is necessary to investigate the molecular regulatory mechanisms in the formation of ARs of A. ruburm. To address this knowledge gap, we sequenced the transcriptome and sRNA of the A. rubrum variety ‘Autumn Fantasy’ using high-throughput sequencing and explored changes in gene and microRNA (miRNA) expression in response to exogenous auxin treatment. ResultsWe identified 82,468 differentially expressed genes between the treated and untreated ARs, as well as 48 known and 95 novel miRNAs. We also identified 172 target genes of the known miRNAs using degradome sequencing. Two regulatory pathways (ubiquitin mediated proteolysis and plant hormone signal transduction), Ar-miR160a and the target gene ArARF10 were shown to be involved in the auxin response. We further investigated the expression patterns and regulatory roles of ArARF10 through subcellular localization, transcriptional activation, plant transformation, qRT-PCR analysis, and GUS staining. ConclusionsDifferential expression patterns indicated the Ar-miR160a-ArARF10 interaction might play a significant role in the regulation of AR formation in A. rubrum. Our study provided new insights into mechanisms underlying the regulation of AR formation in A. rubrum.

El objetivo principal del experimento fue comprobar y mostrar al productor la forma correcta de siembra y manejo del cultivo de vainilla enriqueciendo el acahual con tutores de Gliricidia sepium para generar ingresos en la región asociado a la producción de vainilla, además de integrar a personas de la comunidad en las diferentes actividades del huerto. Las variables de respuesta utilizadas fueron crecimiento de brotes, distancia entre nudos, días de formación de raíces terrestres, número de hojas, longitud y ancho de las hojas encontrando que las condiciones edafoclimáticas de la Sierra Otontepec, Veracruz son perfectamente viables para el cultivo de Vanilla planifolia A, incitando a la comunidad a crear más huertos en toda la región, ya que el experimento presentó una excelente adaptación a pesar de que la época de siembra de los esquejes no fue la indicada.

In this experiment the combined effect of cutting size (15, 20 and 25 cm), number of buds on cuttings (1, 2 and 3) and planting soft wood cutting in potatoes and without potatoes was studied relative to the sprouting of axillary buds and adventitious root formation of 3 months old rose semi hardwood cuttings. The experiment was replicated at two different times. First, the experiment was conducted in 2016 to study the effects of high elevation. Furthermore, the roses were cultivated in high elevation and was planted in low elevation. While in the second experiment the roses were cultivated in low elevation and was planted in the same elevation. In the first experiment, even though, most of the cuttings sprouted in the initial stage of development, but none of them produced roots. In the second experiment, cuttings planted in soil, leaves were developed and also most of them produced roots, while those cutting planted in potatoes, most of the cuttings sprouted in the initial stage of development, but none of them produced roots. In terms of cutting size and bud number, from the second experiment it was revealed that the numbers of bud and cutting size have significant effects on both shoot length (p < 0.001), (p= 0.009) and root formation (p< 0.001), (p= 0.022) , respectively. It was also found out that the two factors together (bud number and cutting size) have significant effect (p < 0.001) on both shoot elongation and root formation. The test of least significant difference (LSD) suggested that those treatments having 15 cm cutting size and 2 buds are significantly different in terms of both sprouting and roots formation.

Luehea divaricata, conhecida popularmente como açoita-cavalo, é uma espécie florestal nativa da Mata Atlântica muito utilizada para a recuperação de áreas degradadas. Sua madeira pode ser empregada para as mais diversas finalidades, o que contribuiu para a redução de suas populações naturais e ocasionou dificuldades na obtenção de sementes com qualidade genética, fisiológica e sanitária para uso na produção de mudas. Sendo assim, a micropropagação é uma alternativa para a produção de mudas da espécie para uso em projetos ambientais. Com isso, o presente trabalho teve como objetivo otimizar o processo de rizogênese in vitro e, para isso, foram avaliadas, inicialmente, diferentes concentrações de sais do meio nutritivo WPM. Em seguida, foram estudados os efeitos do ácido indolbutírico (AIB), adicionado ao meio em tratamento “pulse” por 15 dias, e do ácido naftalenoacético (ANA), na rizogênese, em ambos os casos em cultivo em meio WPM cuja concentração de sais foi reduzida à metade (WPM/2). Por fim, também foi analisado o efeito da combinação de volumes de vermiculita com WPM/2. Os resultados indicaram que o meio WPM/2 apresentou resultados promissores para o estabelecimento (98%) in vitro e, no que diz respeito à formação de raízes adventícias primárias, após 45 dias de cultivo in vitro observaram-se as maiores médias (40,52%), independentemente da concentração de sais do meio. O tratamento “pulse” após 30 dias de cultivo in vitro, independentemente da concentração de AIB, resultou em uma média de 25,18% de formação de raízes adventícias primárias. As combinações de 20 mL + 15 cm³, 20 mL + 30 cm³ e 30 mL + 30 cm³ de meio nutritivo e de vermiculita, respectivamente, foram as mais favoráveis para a formação de raízes adventícias laterais de segunda ordem, proporcionando médias entre 38 e 49,5% após 45 dias de cultivo in vitro. Para otimizar o processo de rizogênese de Luehea divaricata é indicado o cultivo in vitro por 45 dias em meio nutritivo WPM/2, combinado com vermiculita, prescindindo da adição de auxinas.

Relevance Biotechnological methods are generally used to speed up breeding programs and to enhance genetic diversity, so the culture of isolated microspore in vitro can be regarded as one of very suitable methods. Nontraditional and uncommon vegetable crops belonging to Brassicaceae Burnett. are becoming more popular. Methods Accessions of sarepta mustard (Brassica juncea L. Czern.) and rocket salad (Eruca sativa Mill.) were taken for the study with the aim to optimize the basic protocol for these species. Results As a result of the study the optimum cultivation conditions have been determined for the species. Sizes of buds 2.5-3.5 mm long for sarepta mustard and 7.0-7.5 long for rocket salad which were used for cultivation had been experimentally defined. It was also shown that the cold pretreatment had improved the embryo yield. The nutritional NLN-13 medium with pH 6.1 and pretreatment at 32°C during a cultivation day had been shown to be more favourable for all accessions. All conditions that had been used were suitable for embryo formation. First divisions had been seen after 4 days of cultivation, while the embryos at primary cotyledonary stage only appeared after 2 weeks of cultivation. The embryo yield per 5 buds reached 25-30 and 5-7 in the sarepta mustard and the rocket salad, respectively. It is worth noticing that the root formation and plant adaptation had passed better and faster in sarepta mustard than in rocket salad. Thus, whole process of homozygous line developing can be completed for 4-5 months, making the breeding program 3 times shorter.

Nepeta binaloudensis Jamzad is a medicinal plant endemic to Iran. It is an endangered plant due to habitat destruction and intensive harvest. We investigated the effect of antioxidants and different concentrations of BAP and NAA on in vitro stem and root formation of N. binaloudensis. Stem explants were cultured in ½ MS medium supplemented with BAP (0.5 mg/L) and different concentrations of ascorbic acid and reduced glutathione. The effect of different concentrations of BAP on the regeneration of this plant was then evaluated. Moreover, root formation of regenerated stems was investigated in the ½ MS medium supplemented with different concentrations of NAA. The results showed that the combination of antioxidants in ½ MS medium supplemented with BAP (0.5 mg/L) had a significant effect on regeneration in vitro culture. The reduced-glutathione (2 μM/ L) in comparison with other antioxidant treatments increased the stem regeneration in explants. The levels of BAP hormone (1 and 1.5 mg/L) had a significant (p-value

MicroRNAs (miRNAs) have been shown to play key roles in the regulation of plant growth and development by modifying the expression of their target genes. However, the influence of miRNAs on root formation and development in woody plants, such as Taxus chinensis, remains largely unknown. In the current study, we explored the phytohormone-response and nutrition-response miRNA expression profiles during T. chinensis rooting by quantitative real-time PCR (qPCR). We identified six phytohormone-response miRNAs, namely, miR164a, miR165, miR167a, miR171b, miR319, and miR391, and eight nutrition-response miRNAs, namely, miR169b, miR395a, miR399c, miR408, miR826, miR827, miR857, and miR2111a, that were differentially expressed at different rooting phases of T. chinensis. Using northern blot analysis of the putative target genes of these miRNAs, we detected the relative gene expression changes of the target genes. Taken together, our results suggest that miRNAs are involved in root formation of T. chinensis and that miRNAs may play important regulatory roles in primary root, crown root, and root hair formation by targeting phytohormone and/or nutrition response genes in T. chinensis. For the first time, these results expand our understanding of the molecular mechanisms of plant root formation and development in a conifer species.

Background: Blueberry (Vaccinium corymbosum L.) is one of the most important commercial fruit tree species. The development of high-quality seedlings is a prerequisite for fruit production. Stem cutting and tissue culture methods are widely applied for propagating blueberry seedlings. Both methods require adventitious roots (ARs), indicating ARs are critical for vegetative propagation. However, the underlying factors and molecular mechanisms regulating blueberry AR formation remain relatively unknown. Results: In this study, the rooting abilities of differentially lignified cuttings from various cultivars or the same cultivars cultured differently were evaluated following an indole-3-butyric acid (IBA) treatment. Field-grown semi-lignified and tissue culture-grown cuttings formed ARs, but the latter had more pericycle and secondary xylem cells and formed ARs more easily and faster. WUSCHEL-related homeobox genes are commonly involved in vascular tissue development and early root meristem maintenance. On the basis of the available Vaccinium corymbosum genome data, 29 putative WOX genes with conserved homeodomains were identified and divided into three major clades (modern/WUS, intermediate, and ancient). These 29 WOX genes were differentially expressed in the root, shoot, leaf, flower bud, and fruit. Additionally, a qRT-PCR analysis revealed that five selected VcWOX genes were responsive to an IBA treatment during AR formation. Accordingly, VcWOX4b was functionally characterized. The overexpression of VcWOX4b in transgenic tobacco inhibited AR formation by altering vascular cell division and differentiation and the indole-3-acetic acid (IAA):cytokinin (CTK) ratio. These observations suggest that VcWOX4b regulates the IAA:CTK ratio to promote primary xylem cell differentiation, thereby inhibiting AR formation. However, an IBA treatment can induce AR formation by inhibiting VcWOX4b expression. Conclusions: Current study elucidates the rooting abilities of various cultivars and the cytological characters of influence on AR formation of blueberry cuttings, which may provide novel insights into the selection of high-quality blueberry cuttings. VcWOX4b, VcWOX8/9a, VcWOX11/12c, and VcWOX13b might regulate blueberry AR formation in an IBA-dependent manner. Ectopic expression of VcWOX4b modulated the IAA:CTK ratio to promotes primary xylem cell differentiation, but inhibit secondary xylem cell differentiation, ultimately leading to decreased AR formation.

BarkgroundAdventitious roots (ARs), which are considered as an important member of root system, have an unmatched status in plant growth and metabolism due to the degeneration of primary roots in lotus. The regulation of AR formation was previously revealed and multiple factors were recognized to be involved in this biological process. ResultsIn the present study, we sought to assess the effect of sucrose on AR formation. Based on our results, lignin metabolism, which is regulated by the sucrose signal transduction pathway, is involved in AR development. The lignification degree of the AR primordium was weaker in plants treated with 20 g/L sucrose than in control plants. However, based on the microstructural observation of the AR developmental process, 50 g/L sucrose promoted the lignification process. Lignin content, including monomer and polymer lignin, was determined in the present study. Compared with control plants, the monomer (containing 30%–45% S type and 55%–70% G type) and polymer lignin contents were lower in plants treated with 20 g/L sucrose and higher in plants treated with 50 g/L sucrose. The precursors of monomer lignin were identified in four libraries of differential developmental stages in seedlings using LC-MS/MS technique. The contents of four metabolites, including p-coumaric acid, caffeate, sinapinal aldehyde and ferulic acid for monomer lignin synthsis were lower in the GL50 library than in the GL20 library. Further analysis revealed that the gene expression of these four metabolites had no novel difference in the GL50/GL20 libraries. However, NnLAC17, a gene involved in polymer lignin synthesis, had a higher expression in the GL50 library than in the GL20 library. ConclusionsTherefore, NnLAC17 was cloned, and the overexpression of NnLAC17 was found to directly result in a decrease in AR number in transgenic Arabidopsis plants. These findings suggest that NnLAC17, which is relevant to lignin synthesis, is involved in AR formation in lotus seedlings.

Irregular rooting of rosemary stem cuttings, causing differences in either stem maturation or responses to growth conditions, restricts uniform production. Here, rooting efficiency of apical, middle, and basal cuttings from rosemary stems was evaluated by controlling light conditions to prevent irregular rooting. The types of light applied to the cuttings were natural sunlight (NSL), fluorescent, red, and blue (BL) light. Among these light sources, BL significantly induced root growth of not only basal cuttings, but also apical and middle cuttings, whereas NSL induced poor root formation in apical and middle cuttings. In particular, the roots of apical cuttings exposed to BL grew twice as fast as those exposed to other types of light. The overexpression of BL-induced IAA synthetic genes confirmed the rooting patterns. IAA synthetic genes were significantly upregulated by BL in the apical and middle cuttings. Irradiating with 50 μmol photons m−2 s−1 BL resulted in similar root production levels among the cutting positions with high biomass, guaranteeing the successful production of uniform cuttings. Thus, the application of proper high-intensity BL promoted healthy, similar-quality rosemary cuttings among stem cutting positions.

Adventitious root formation is a postembryonic organogenesis process induced by differentiated cells other than those specified to develop roots [...]

The article presents data on the complex influence study of new microbial preparations Diazophyte, Phosphoenterin, Biopolicide, Aurill and Azotobacterin on biometric indicators of growth and development of grapes rootstock at separate rhizogenesis stages. Standard cuttings of the Berlandieri x Riparia Kober 5 BB rootstock grape variety were used as objects of the four-year study. For the first time, the optimal breeding range of the studied microbial complexes (MPC-1 and MPC-2 in dilution 1:10) was determined; with it, stable efficiency of root formation stimulation of subpar grape variety Berlandieri x Riparia Kober 5BB cuttings was observed. In turn, this is the basis for future studies aimed at finding the optimal concentration in this range. By its effectiveness, the use of these microbial complexes approaches the action of the traditional chemical stimulant Heteroauxin at a concentration of 0.02%.

MADS-box genes are important transcription factors affecting overall development, but their role in sweet potato [Ipomoea batatas (L.) Lam.] has not been fully studied. This study isolated six novel MADS-box genes (IbSOC1, IbFUL1, IbAGL6, IbSVP1, IbSVP2, and IbSVP3) from sweet potato [Ipomoea batatas (L.) Lam. cv. Annouimo] during the early root differentiation stage using the de novo transcriptome assembly sequencing method. At the early root differentiation (between 0 and 3 days after transplanting), the IbSOC1, IbFUL1, and IbSVP2 genes decreased rapidly, whereas the IbSVP3 gene decreased gradually. In the early stages of root formation (0-30 days), the levels of IbSVP1 and IbSVP3 expression were steady, but the levels of IbSOC1 expression decreased gradually. The expression of six novel genes was also conducted in the tuberous root formation stage (30-90 days), and the IbSVP3 gene increased significantly according to the formation of the tuberous root. Six novel MADS-box genes that were believed to influence the entire root formation of sweet potato were isolated from the sweet potato. This study provides a genetic basis for further research on sweet potato root formation and development.

Adventitious root formation is an organogenic process, regulated at several levels, that is crucial for the successful vegetative propagation of numerous plants. In many tree species, recalcitrance to adventitious root formation is a major limitation in the clonal propagation of elite germplasms. Information on the mechanisms underlying the competence for adventitious root formation is still limited. Therefore, increasing our understanding of the mechanisms that enable differentiated somatic cells to switch their fates and develop into root meristematic cells, especially those involved in cell developmental aging and maturation, is a priority in adventitious root-related research. The dynamic cell wall–cytoskeleton, along with soluble factors, such as cellular signals or transcriptional regulators, may be involved in adult cell responses to intrinsic or extrinsic factors, resulting in maintenance, induction of root meristematic cell formation, or entrance into another differentiating pathway.

The aim of the study was to find an efficient culture medium for regeneration of Physalis species in vitro to provide their further propagation ex vitro and obtain fructiferous plants from the regenerants. Physalis peruviana L., P. ixocarpa Broth. (cv. Likhtaryk), and P. pubescens L. (cv. Zarynka) were taken as plant material for the research. Plant introduction into culture and regenerant production were carried out in vitro; the rooting of mature plants and obtaining plants with ripe fruits took place in a greenhouse and in open ground (ex vitro). To obtain regenerants, we used Murashige and Skoog (MC30) medium supplemented with the growth stimulant zeatin (Zea) at a concentration of 0.5–3 mg/l. The growth stimulant 6-benzylaminopurine (BAP) was used to elongate the regenerant stalks, and the growth stimulator α-naphthylacetic acid (NAA) was used to initiate root formation. Plant regeneration frequency and the number of regenerants per explant served as indicators of the efficiency of various zeatin concentrations on the physalis regenerative capacity. The most effective media for the shoot regeneration from cotyledonous leaf explants were MC30 + 1 mg/l Zea and MC30 + 2 mg/l Zea. Regeneration frequency on these media was 46.15 % and 53.84 % for P. ixocarpa (cv. Likhtaryk), 38.46 % and 45 % for P. peruviana, and 27 % and 34 % for P. pubescens (cv. Zarynka) respectively. The emerged regenerants were separated from explants and transferred to MC30 medium supplemented with 1 mg/l of BAP + 0.1 mg/l of NAA for stalk growth and rooting. After a month of cultivation, juvenile plants were obtained. They were transferred to a greenhouse for adaptation, and later to open ground at the experimental plot. Three months after the regenerant emergence, we obtained fertile plants, which bloomed and bore fruit. The regenerants for domestic varieties of P. ixocarpa (cv. Likhtaryk) and P. pubescens (cv. Zarynka) were obtained for the first time. We established a direct relationship between the concentration of zeatin and both the frequency of plant regeneration and the number of regenerants per explant.

For woody plants, clonal propagation efficiency is largely determined by adventitious root (AR) formation at the bases of stem cuttings. However, our understanding of the molecular mechanisms contributing to AR morphogenesis in trees remains limited, despite the importance of vegetative propagation, currently the most common practice for tree breeding and commercialization. Here, we identified Populus-specific miR476a as a regulator of wound-induced adventitious rooting that acts by orchestrating mitochondrial homeostasis. MiR476a exhibited inducible expression during AR formation and directly targeted several Restorer of Fertility like (RFL) genes encoding mitochondrion-localized pentatricopeptide repeat proteins. Genetic modification of miR476a-RFL expression revealed that miR476a/RFL-mediated dynamic regulation of mitochondrial homeostasis influences AR formation in poplar. Mitochondrial perturbation via exogenous application of a chemical inhibitor indicated that miR476a/RFL-directed AR formation depends on mitochondrial regulation that acts via auxin signaling. Our results thus establish a microRNA-directed mitochondrion-auxin signaling cascade required for AR development, providing insights into the role of mitochondrial regulation in the developmental plasticity of plants.

SMALL AUXIN-UP RNAs (SAURs) comprise the largest family of early auxin response genes. Some SAURs have been reported to play important roles in plant growth and development, but their functional relationships with auxin signaling remain unestablished. Here, we report Arabidopsis (Arabidopsis thaliana) SAUR15 acts downstream of the auxin response factors ARF6,8 and ARF7,19 to regulate auxin signaling-mediated lateral root (LR) and adventitious root (AR) formation. The loss-of-function mutant saur15-1 exhibits fewer LRs and ARs. By contrast, plants overexpressing SAUR15 exhibit more LRs and ARs. We find that the SAUR15 promoter contains four tandem auxin-responsive elements, which are directly bound by ARF6 and ARF7 and are essential for SAUR15 expression. LR and AR impairment in arf6 and arf7 mutants is partially reduced by ectopic expression of SAUR15. Additionally, we demonstrate that the ARF6,7-upregulated SAUR15 promotes LR and AR development using two mechanisms. On the one hand, SAUR15 interacts with PP2C-D subfamily type 2C protein phosphatases to inhibit their activities, thereby stimulating plasma membrane H(+)-ATPases, which drives cell expansion and facilitates LR and AR formation. On the other hand, SAUR15 promotes auxin accumulation, potentially by inducing the expression of auxin biosynthesis genes. A resulting increase in free auxin concentration likely triggers LR and AR formation, forming a feedback loop. Our study provides insights and a better understanding of how SAURs function at the molecular level in regulating auxin-mediated LR and AR development.

Adventitious root (AR) formation is a complex developmental process controlled by a plethora of endogenous and environmental factors. Based on fossil evidence and genomic phylogeny, AR formation might be considered the default state of plant roots, which likely evolved independently several times. The application of next-generation sequencing techniques and bioinformatics analyses to non-model plants provide novel approaches to identify genes putatively involved in AR formation in multiple species. Recent results uncovered that the regulation of shoot-borne AR formation in monocots is an adaptive response to nutrient and water deficiency that enhances topsoil foraging and improves plant performance. A hierarchy of transcription factors required for AR initiation has been identified from genetic studies, and recent results highlighted the key involvement of additional regulation through microRNAs. Here, we discuss our current understanding of AR formation in response to specific environmental stresses, such as nutrient deficiency, drought or waterlogging, aimed at providing evidence for the integration of the hormone crosstalk required for the activation of root competent cells within adult tissues from which the ARs develop.

One of the biggest challenges in clonal propagation of grapevine (Vitis vinifera) is difficulty of rooting. Adventitious root initiation and development are the critical steps in the cutting and layering process of grapevine, but the molecular mechanism of these processes remains unclear. Previous reports have found that microRNA (miRNA)-encoded peptides (miPEPs) can regulate plant root development by increasing the transcription of their corresponding primary miRNA. Here, we report the role of a miPEP in increasing adventitious root formation in grapevine. In this study, we performed a global analysis of miPEPs in grapevine and characterized the function of vvi-miPEP171d1, a functional, small peptide encoded by primary-miR171d. There were three small open reading frames in the 500-bp upstream sequence of pre-miR171d. One of them encoded a small peptide, vvi-miPEP171d1, which could increase the transcription of vvi-MIR171d. Exogenous application of vvi-miPEP171d1 to grape tissue culture plantlets promoted adventitious root development by activating the expression of vvi-MIR171d. Interestingly, neither exogenous application of the vvi-miPEP171d1 peptide nor overexpression of the vvi-miPEP171d1 coding sequence resulted in phenotypic changes in Arabidopsis (Arabidopsis thaliana). Similarly, application of synthetic ath-miPEP171c, the small peptide encoded by the Arabidopsis ortholog of vvi-MIR171d, inhibited the growth of primary roots and induced the early initiation of lateral and adventitious roots in Arabidopsis, while it had no effect on grape root development. Our findings reveal that miPEP171d1 regulates root development by promoting vvi-MIR171d expression in a species-specific manner, further enriching the theoretical research into miPEPs.

Background Melatonin (MT) plays a key role in the plant growth and development, however, whether MT involved in apple adventitious root (AR) development is not entirely understood. In present study, we set up four MT-treated groups at different times according to the stages of AR development and one control group in Malus domestica (MP), endogenous hormones levels of MT, auxin (IAA), zeatin-riboside (ZR), gibberellins (GA1 + 3), abscisic acid (ABA) were analyzed in five groups, then the expression of MT signal, IAA synthesis, transport, and signal transduction, cell cycle, and root development related genes were measured by RT-qPCR, the function of MdWOX11 was analyzes by technology of apple transgenic. Results Advance of AR development by MT is depended on its promotion of stage of AR induction at 0–2 d in the apple rootstocks. MT-treated increased IAA levels, there were crosstalk between MT and IAA during inducing AR formation. Expression analysis exposed that the expression of MdWOX11 induced by MT-treatment, and positively regulated AR formation in apple. Furthermore, MdWOX11 over-expressed lines produced more ARs than ‘GL3’, phenotypic analysis indicated that MdWOX11 over-expressed lines were more sensitive to exogenous MT-treatment than ‘GL3’, it was also indicated that MdWOX11 regulated AR formation in response to MT in apple rootstock. Conclusions MT promotes AR formation mainly during AR induction stage by inducing IAA levels as well as by up-regulation of MdWOX11.

Ganoderma is a major pathogen in oil palm crops. Some efforts related to control the growth of Ganoderma have been conducted but still have not found an effective method. This study aims to develop an organic fungicide that has been tested in vitro , which effective in controlling the growth of Ganoderma . The optimization carried out includes the determination of the dose and time interval for application in 13-year-old mature oil palm. This organic fungicide application was the continuation of application during the previous year especially for the two best treatment which is application organic fungicide every week (1w) and every two weeks (2w). In this study, the treatments tested were three levels dose of organic fungicide (0, 1x and 2x) and two types of frequency application, i.e. every week (1w) and every other week (2w). The results showed that the best application of organic fungicides was every week application with twice doses (1w.2x), based on the parameters of the inhibition of Ganoderma’s fruiting body formation, primary and secondary root formation, the opening of spear leaves, and harvesting parameters. The application of organic fungicide able to recover the oil palm infected Ganoderma sp., with increasing the fresh fruit bunch and its weight around 70% and 78%, respectively .

Leaves of mate is one of the main non-timber forest products marketed in South America, which makes establishment of new plantations of great interest. However, vegetative propagation of mate plantlets presents difficulties, which may be associated with the complexity of adventitious root formation. The aims of this study were to anatomically characterize the adventitious roots of mate-clone mini-cuttings and investigate the relationship of phenols and starch with adventitious rooting competence in mini-cuttings treated or not with indole-butyric acid (IBA). The mini-cuttings of four clones were collected at 0, 30, and 60 days of cultivation, fixed in a solution containing 1% glutaraldehyde and 4% formaldehyde, pre-infiltrated and infiltrated in (2-hydroxyethyl) methacrylate, and sectioned in a microtome. Ferric chloride and toluidine blue were used to detect phenolic compounds and lugol to identify starch. Adventitious roots formed in mini-cuttings treated with IBA presented disorganized xylem and phloem and poles irregularly but exhibited sclerenchyma vessel elements and tracheid cells indicating functionality. Differences in the rhizogenic ability of mate clones mini-cuttings were not due to the presence of anatomical barriers or the accumulation of phenolic compounds but be associated with the presence and distribution of starch grains in vegetative propagules.

Prunus genus species are widely spread in semi-arid regions due to their ability to adjust to the limited water supply. Former research described the effect of water deficit on their aboveground development. However, less is known about the effects of water stress on the development of the root system. In order to investigate the effects of the irrigation regime on the root system development, young plum (Prunus cerasifera) trees were grown under three irrigation regimes for a period of five months. The effects of the irrigation regime on different root order and total root system elongation, biomass growth and tip numbers were analyzed. The results indicate that the responses vary according to the stress level. Under moderate stress, the total root system biomass decreases relative to the full irrigation treatment. However, low-order root formation remains similar to that found under no stress conditions. Under severe stress, the formation of low-order roots is also inhibited. Our results suggest...

SUMMARY: Sequoia sempervirens is a fast-growing, long-lived tree with pest-resistant wood. The objective of this study was to quantify the adventitious rooting ability of sequoia clones in two environments as well as determining rooting behavior during the evaluation period. Mini-cuttings of five clones grown in a clonal mini-garden were planted for rooting in two different environments: a mini-tunnel and an intermittently fogging greenhouse. Weekly assessments (from 30 to 93 days) of the variables were performed: survival, rooted mini-cuttings and number of roots emitted. Rooting speed varied in relation to the clones, occurring mainly between 50 and 60 days after planting, with the appearance of new roots between 70 and 80 days. The cultivation environment promoted distinct responses in the rooting process, being earlier in the greenhouse environment, although with a higher index in the mini-tunnel at the end of the evaluation. The process of differentiation of mini-cuttings occurs initially with the formation of calluses, around 15 days, followed by rooting (between 30 and 60 days) and the subsequent appearance of new roots. The rooting of sequoia mini-cuttings can be done in a mini-tunnel, with good indexes for all clones. It is recommended to keep mini-cuttings in this environment for 90 days for good root formation.