Root Formation In Stem Cuttings Research Articles

Iron Chelate Improves Rooting in Indole-3-Butyric Acid-Treated Rosemary (Rosmarinus officinalis) Stem Cuttings

Adventitious root formation in stem cuttings is affected by exogenous and endogenous factors. The study assessed the effect of Fe(III)-EDDHA (ethylenediamine-N,N-bis 2-hydroxyphenyl acetic acid) on the rooting of 4 indol-3-butyric acid (IBA)-treated hardwood cuttings of the aromatic and medicinal species Rosmarinus officinalis. Cuttings treated with 0, 1000, 2000 or 3000 mg L−1 IBA were placed in pots filled with sand:perlite mixture and irrigated daily with nutrient solution pH 5.8, containing 0, 5, 10 or 20 µM Fe(III)-EDDHA. Ten days later, the number of new emerging roots were recorded. After 20 days, leaf photosynthetic pigments and morphological traits, including root number, fresh (FW) and dry weight (DW), shoot FW and DW, mean length of the longest roots, number of new shoots and new growth in old shoots, were measured. Finally, plants were transplanted to pots filled with a sand:soil mixture and survival was measured after 10 days. Results indicate that Fe application promotes root emergence and improves root and shoot biomass, leaf photosynthetic pigment concentrations and survival percentage. This indicates that using low concentrations of Fe(III)-EDDHA (5–20 µM) in the growth medium could be a good management strategy to facilitate the production of vigorous R. officinalis plants from hardwood cuttings.

Effect of naphthalene acetic acid on sprouting and rooting of stem cutting in Mussaenda species

Mussaendas are increasingly popular for the showy colour they provide during much of the year in garden landscapes. However, root formation in stem cuttings is a major challenge for cultivation of Mussaenda species. Therefore, the experiment was carried out at the Landscaping section of the Department of Horticulture, Bangladesh Agricultural University, Mymensingh during the period from August to November 2018 to study the effect of phytohormone naphthalene acetic acid (NAA) on sprouting and rooting of stem cuttings in Mussaenda species. The two-factor experiment consisted of three Mussaenda species viz., Mussaenda frondosa (White flag bush), Mussaenda philippica (Pink flag bush) and Mussaenda erythrophylla (Red flag bush), and five concentrations of NAA viz., 0 (control), 0.1%, 0.2%, 0.3% and 0.4%. The experiment was laid out in randomised complete block design (RCBD) with three replications. The results revealed that all the traits related to sprouting and rooting potential of stem cuttings were significantly influenced by combined effects of Mussaenda species and various NAA concentrations. The maximum sprouted bud per cutting (3.57), highest number of roots per cutting (5.88) and the longest root length (4.32 cm) were recorded from M. philippica except number of leaves per stem cutting (4.42) in M. erythrophylla. The increasing concentrations of NAA application responded positively on sprouting and rooting characters in all three Mussaenda species used for this experiment. The best results obtained from the treatment where NAA was applied at the concentration of 0.3% with 3.92 sprouted buds per cutting, 4.77 leaves per cutting, 7.15 roots per cutting and 5.26 cm length of roots. The treatment combination of M. philippica (Pink flag bush) and 0.3% NAA, followed by NAA at 03% with M. erythrophylla (Red flag bush) was found to be best in terms of sprouting and rooting of stem cuttings in Mussaenda.
 Progressive Agriculture 30 (1): 48-54, 2019

Mechanisms Underlying the Regulation of Root Formation in Malus hupehensis Stem Cuttings by Using Exogenous Hormones

Malus hupehensis is one of the most important Malus ornamental and rootstock species in the south China Yellow River Basin. In the present study, we treated the stem cuttings of M. hupehensis with one of three exogenous hormones, indole acetic acid (IAA), naphthalene acetic acid (NAA), or a compound plant growth regulator (GGR) to investigate the mechanisms underlying root formation in stem cuttings and to optimize stem cutting propagation techniques. The results showed that immersing the stem cuttings in 100 mg/L of IAA for 2 h before planting was most effective, which reduced the time to root formation by 21 days and increased rooting percentage by 129.4 %, compared to that in the control group. In addition, the levels of endogenous substances (endogenous hormones, soluble proteins, and carbohydrates) dynamically changed, with the time to peak value or time to valley value of each parameter synchronized well with the initiation of adventitious roots. The synchronized change suggested that root formation was coordinated with physiological metabolism. However, exogenous hormone treatment significantly accelerated the catabolism of the root inhibiting hormone, abscisic acid. On the other hand, exogenous hormone treatment significantly enhanced the accumulation of root promoting hormones [IAA, gibberellic acid (GA3), and zeatin riboside (ZR)] and soluble proteins. Moreover, exogenous hormone treatments accelerated the consumption of starch and soluble sugars. Overall, the results indicated that exogenous hormone treatment (IAA) accelerated the synthesis of endogenous hormones (IAA, GA3, and ZR), therefore, sped up the metabolism of carbohydrates and soluble proteins, and consequently quickened the root formation process.

Ageing delays the cellular stages of adventitious root formation in pine

Summary Vegetative propagation programs internationally are affected by the significant decline of rooting success as trees mature. This study compared the cellular stages of root formation in stem cuttings from 15-week-old (juvenile) and 9-y-old (mature) stock plants of the slash × Caribbean pine hybrid (Pinus elliottii var. elliottii × P. caribaea var. hondurensis). The cellular stages of root formation were the same in both juvenile and mature cuttings, beginning with cell divisions of the vascular cambium forming callus tissue. Within the callus, tracheids differentiated and elongated to form root primordia. Roots in juvenile cuttings developed faster than those in mature cuttings and the juvenile cuttings had a much higher rooting percent at the end of the study (92% and 26% respectively). Cuttings of the two juvenile genotypes had more primary roots (5.5 and 3.3) than the three mature genotypes (0.96, 0.18 and 0.07). The roots of juvenile cuttings were more evenly distributed around the basal circumference when compared with those on cuttings from the mature genotypes. Further work is needed to improve understanding of physiological changes with maturation so that the rooting success and the speed of development in cuttings from mature stock plants can be optimised, hence improving genetic gain.

Adventitious Root Formation in Stem Cuttings of Quercus bicolor and Quercus macrocarpa and Its Relationship to Stem Anatomy

This study investigated the relationship of stem anatomy to differences in rooting ability between Quercus bicolor Wild. and Quercus macrocarpa Michx. cuttings. Quercus bicolor cuttings were found to have a significantly greater proportion of parenchymatous gaps in the sclerenchyma sheath over a 9-week period compared with Q. macrocarpa cuttings. In Q. macrocarpa, the percentage gap was generally low, coinciding with the low percentage rooting observed in this species. Percentage rooting correlated well (r2 = 0.75) with the percentage parenchymatous gap in the perivascular region of Q. bicolor cuttings. The problems with accepting this relationship as causal are stated in the discussion. Untreated cuttings showed normal stem organization: a dermal tissue system that included the initial stages of phellem formation, a cortex, and a ring of closely arranged vascular bundles in early stages of secondary growth. The locations of the five distinct lobes of the pith were coordinated with the locations of root primordia. Callus growth was first detected in the cortex (i.e., external to the fiber bundles), followed by proliferation within the phloem, opposite the lobes of the pith, 8 to 12 days after cuttings were treated with indole butyric acid (6000 mg·L−1 dissolved in 50% v/v ethanol in water). By 14 to 16 days, root primordia had developed within the proliferative tissue in the secondary phloem. In both species, root primordia penetrated parenchymatous gaps in the fiber sheath directly, the fiber bundles being displaced laterally as the roots increased in size.

Vegetative propagation of Ulmus villosa: effects of plant growth regulators, collection time, type of donor and position of shoot on adventitious root formation in stem cuttings

Techniques for the vegetative propagation of Ulmus villosa, an indigenous agroforestry tree species of the north-western sub-Himalayas, were developed. Studies investigated the effects on rooting of stem cuttings of growth regulators with sucrose and fungicide (0%, 0.2% p-HBA + 5% sucrose + 5% captan, and IBA concentrations ranging from 0.2 to 1.0% plus each containing, 0.2% p-HBA + 5% sucrose + 5% captan). Cuttings were collected at two times of the year (February and July) from two types of stock plant (seedling and mature trees) and from two positions within the shoots (lower and upper nodes). Cuttings collected in February were leafless, while those collected in July had about 80 cm2 leaf areas. These cuttings were then set under a mist unit. Percentage rooting and primary root number differed significantly between treated and untreated cuttings. Treatment of cuttings with chemical formulations of 0.4% IBA + 0.2% p-HBA + 5% sucrose + 5% captan maximized rooting (82.0%), while, survival (80%) and primary root number (14.7) were greatest with: (i) 0.6% IBA + 0.2% p-HBA + 5% sucrose + 5% captain and (ii) 0.8% IBA + 0.2% p-HBA + 5% sucrose + 5% captan, respectively. Rooting success and root number were better in propagules set in February rather than in July. Cuttings from seedlings rooted better, with more roots ensuring better survival, than cuttings from mature trees (12–13-years-old). In cuttings from seedlings, those cuttings collected from the lower part of the shoots had greater percentage rooting and primary root number than those from the upper part. Maximum root regeneration (100%), roots number (19.0), and survival (98.5%) were achieved when the time of collection (February) and shoot position were optimized. Rooting was best when cuttings had higher levels of sugar, total carbohydrate and peroxidase enzyme activity, and low N.

Mist, Vapor Pressure Deficit, and Cutting Water Potential Influence Rooting of Stem Cuttings of Loblolly Pine

Producing high quality rooted stem cuttings on a large scale requires precise management of the rooting environment. This study was conducted to investigate the effect of the rooting environment on adventitious root formation of stem cuttings of loblolly pine (Pinus taeda L.). Hardwood stem cuttings of loblolly pine were collected in Feb. 2002 from hedged stock plants and stored at 4 °C until setting in Apr. 2002. One hundred stem cuttings per plot in each of two replications received 45, 61, 73, 102, 147, or 310 mL·m-2 of mist delivered intermittently by a traveling gantry (boom) system. Mist frequency was similar for all treatments and was related inversely to relative humidity (RH) within the polyethylene covered greenhouse. Rooting tubs in each plot were filled with a substrate of fine silica sand, and substrate water potential was held constant using soil tensiometers that activated a subirrigation system. Cutting water potential was measured destructively on two cuttings per plot beginning at 0500 hr every 3 hh until 2300 hr (seven measurements) 7, 14, 21, or 28 days after setting. During rooting, leaf temperature and RH were recorded in each plot to calculate vapor pressure deficit (VPD). Cutting water potential and VPD were strongly related to mist application. Cutting water potential was also related to VPD. Rooting percentage had a linear and quadratic relationship with mean cutting water potential and VPD averaged between 1000 and 1800 HR. Eighty percent rooting occurred within a range of values for VPD. Data suggest that VPD can be used to manage the water deficit of stem cuttings of loblolly pine to increase rooting percentage. These results may be applicable to other species and to other rooting environments.

Stimulation of adventitious root formation in non-woody stem cuttings by uridine

Uridine strongly stimulated adventitious root formation in stem cuttings of sunflower (Helianthus annuus L.), mung bean (Vigna radiata L.) and common bean (Phaseolus vulgaris L.). A dose response curve of uridine induced rooting showed that the optimum concentration of uridine was 0.1 µM. At all concentrations employed, uridine had no significant effect on root elongation. The rooting response of stem cuttings to the optimal concentration of indole-3-butyric acid (10 µM) in combination with 0.1 µM uridine did not significantly differ from their response to either of these compounds when applied alone. However, the rooting response of the cuttings to sub-optimal IBA (0.01 µM) was significantly stimulated by uridine. These findings suggested that uridine may have stimulated rooting by increasing the sensitivity of the rooting tissue to auxin.

Adventitious Root Formation in Young Shoots of Cedrus Deodara

The effect of auxins [indole-3-butyric acid (IBA) and α-naphthaleneacetic acid (NAA)], phenolics (phloroglucinol and coumarin), a combination of auxins and phenolics, and a systemic fungicide (Bavistin, containing 50% carbendazim) on adventitious root formation in stem cuttings (current season's growth) of Cedrus deodara L. during winter and monsoon (rainy) seasons has been examined. Significant stimulation of rooting due to treatments was observed in cuttings planted in winter in the following order: 0.25 mM IBA (87.5% rooting) > 5 mM coumarin (70.8%) > IBA (0.5 mM) + coumarin (5 mM) (50.0%). In cuttings planted in monsoon only 0.05% Bavistin was found to be effective in inducing rooting (83.3%). Other treatments were ineffective and in some treatments drying of cuttings was noticed.

ESTAQUIA SEMI-LENHOSA: UM MÉTODO RÁPIDO E ALTERNATIVO PARA A PRODUÇÃO DE MUDAS DE LIMA ÁCIDA 'TAHITI'

Avaliou-se o efeito de várias concentrações e tempos de exposição de dois reguladores de crescimento no enraizamento de estacas de lima ácida `Tahiti' (Citrus latifolia Tanaka). Experimentos complementares também avaliaram a eficiência do enraizamento de estacas de laranjas `Pêra' e `Valencia' (Citrus sinensis L. Osbeck) comparando-a com a da lima ácida `Tahiti'. Os trabalhos experimentais foram conduzidos, em Piracicaba, SP, em câmara de nebulização intermitente, com estacas ponteiro, semi-lenhosas, coletadas 5 meses após a brotação, com 10 cm de comprimento, sem as 3 folhas basais. O delineamento experimental adotado foi o de blocos casualizados com 4 repetições para todos os ensaios realizados. A avaliação dos tratamentos foi realizada 90 dias após a instalação de cada ensaio através da coleta dos seguintes dados biométricos (número médio de raízes/estaca enraizada-NMR, porcentagem de enraizamento-PE, porcentagem de formação de calos-PC, comprimento médio da maior raiz-CMMR e número médio de folhas/estaca enraizada-NMF). Os resultados dos ensaios permitiram as conclusões: a) O enraizamento de estacas de lima ácida `Tahiti' ocorreu com relativa facilidade (PE acima de 50%, podendo chegar a 96%), independentemente da aplicação de reguladores de crescimento; b) Estacas de laranja doce revelaram baixa PE (0,5%), independentemente da utilização de reguladores de crescimento; c) Para cada espécie estudada, não houve diferenças significativas para os parâmetros PC, NMR, CMMR e NMF. Observou-se que a obtenção de mudas de lima ácida `Tahiti' por enraizamento de estacas é um método eficiente e rápido de propagação para essa espécie.

Anatomy of Adventitious Root Formation in Stem Cuttings of Mussaenda erythrophylla L. `Rosea'

Mussaendas (Mussaenda spp.) are ornamental shrubs, and some cultivars are difficult to root. This study was conducted to explore how adventitious roots initiate and develop in the cultivar Rosea, and to determine if anatomical events are associated with difficulty in rooting stem cuttings. Stem cuttings were treated with 5, 10, 15 mm 1H-indole-3-butyric acid (IBA), or distilled water, and sampled every 2 days over 26 days to observe adventitious root formation and development. For analysis by light microscopy, the basal 1 cm of cuttings was embedded in wax and stained with safranin-fast green. Adventitious roots initiated from phloem parenchyma cells and from basal callus in nontreated cuttings. Cuttings treated with 15 mm IBA had a mean of 18 root primordia per basal 1 cm of cutting after 10 days. Root primordia were not observed in non-treated cuttings at 10 days. Root primordia that developed in non-treated cuttings lacked clear vascular connections. These results suggest that non-treated cuttings are difficult to root because few primordia are produced.

The Effect of Stock Plant Water Potential, Auxin Application Method, and a Polyamines on Rooting Walnut Cuttings

Experiments with field-grown hybrid Paradox (Juglans hindsii × J. Regia) walnut trees were conducted to assess the effects of stock plant water status, auxin application method, and the addition of spermine on adventitious root formation in stem cuttings. A 2-fold increase in rooting was noted when semihardwood cuttings were collected from dry (midday Ψw = –1.3 MPa) stock plants compared to the same trees six days later when fully hydrated (midday Ψw = –0.6 MPa). Spermine, when combined with potassium indolebutyric acid (KIBA) and applied as a quick dip, enhanced the rooting percentage in hardwood cuttings (54%) compared to controls treated with KIBA alone (18%). Spermine had no effect when it was applied together with KIBA using a toothpick application, producing 65% rooting compared to controls which had 75% rooting. By itself, spermine had no effect on rooting. The toothpick method for applying rooting compounds resulted in significantly higher rooting percentages for hardwood cuttings, but not for semihardwood cuttings. Combining spermine with KIBA had no effect on rooting of semihardwood cuttings.

Chemical induction of adventitious root formation in Taxus baccata cuttings

The effect of some auxins (IBA and NAA), phenolic compounds (phloroglucinol, gentisic acid and coumarin), a combination of auxins and phenolics, and a systemic fungicide (Bavistin) have been examined for stimulatory effects on adventitious root formation in stem cuttings (current season's growth) of Taxus baccata L. In general lower concentration (0.25 mM) of both IBA and NAA was more effective in inducing rooting of cuttings taken from both male and female trees. The combined treatment of IBA+NAA (0.25 mM each) showed some success in cuttings from male trees only (55%, compared to 15% rooting in cuttings from female trees). Generally, the callus formation was quite high (≥70%) in all auxin treatments (alone or in combination). Among the phenolics, 40% rooting success was achieved with phloroglucinol only, while coumarin and gentisic acid were ineffective. The combined treatment of auxins and phenolics also failed to promote rooting. On the other hand, Bavistin was extremely effective for callusing (≥90%) as well as rooting (80%). The effectiveness of various compounds tested for rooting of young stem cuttings declined in the order: 0.25 mM IBA>0.05% Bavistin>0.25 mM NAA>1.25 mM IBA>15 mM phloroglucinol>IBA+NAA (0.25 mM each). In addition to the auxins, IBA and NAA that are widely used for commercial propagation, the auxin-like properties of the fungicide Bavistin could be exploited for adventitious rooting in T. baccata, and in other plant species.

Plant growth regulators and adventitious root development in relation to auxin

Adventitious root formation in stem cuttings of mung bean was enhanced by ethrel, which had an additive effect when employed simultaneously with indolebutyric acid (IBA). Abscisic acid (ABA) did not influence the number of roots per cutting whereas gibberellic acid (GA3) and kinetin were without effect on rooting at lower concentrations but were inhibitory at higher concentrations. Nevertheless, all three of these chemicals showed synergistic interactions with IBA and/or indol-3-ylacetic acid (IAA) and thereby significantly promoted root formation. A localised application of morphactin to the epicotyl of cuttings totally inhibited root production irrespective of which of the foregoing growth regulators were suppliedvia the hypocotyl. Morphactin application also prevented root formation in cuttings treated with vitamin D2. The various growth regulators employed had differing effects on growth of roots but there was no simple relationship between their effects on root formation and subsequent root growth.

RNA and protein metabolism during adventitious root formation in stem cuttings of Phaseolus aureus

Indole‐3‐butyric acid (IBA, 10−4M), spermine (7 × 10−5M) and vitamin D2 (6.3 × 10−5M), all of which enhance rooting in mung bean cuttings (Phaseolus aureus Roxb. cv. Berkin), influence RNA metabolism. Total and poly (A)+‐RNA synthesis within the hypocotyl is inhibited by each of these chemicals within 24 h. These changes precede induced cell division and are therefore associated with the so‐called inductive period of regeneration during which some cells in the hypocotyl undergo dedifferentiation. However, following subsequent transfer of cuttings to borate, which is an essential prerequisite for development of root primordia in these cuttings, RNA synthesis is enhanced by pretreatments with IBA, spermine or vitamin D2. Furthermore, IBA inhibits synthesis and turnover of protein within the hypocotyl.