Single-node Cuttings Research Articles

Genotypic variability of rooting capacity in Coffea arabica L. cuttings

Cutting propagation of coffee trees has been used for several years in Coffea canephora because of the advantages of this technique compared to seed propagation. Recently, the production of heterotic arabic coffee hybrid genotypes increased the importance of conventional and biotechnological cloning also for C. arabica. Two experiments were carried out to assess cutting rooting of several C. arabica genotypes. In greater detail, the potential of two types of cutting of several hybrid genotypes compared to C. canephora genotypes was investigated. The experiment was carried out under shading with automatic misting in boxes of partially burnt rice husks during the summer months. There is genetic variability for cutting rooting capacity among the C. arabica genotypes. The F 1 hybrids tended to perform better than the lines. Single-node soft-wood cuttings were superior to the tip cuttings. Selection only for cutting rooting characteristics and useable cuttings resulted in efficient selection especially among single-node soft-wood cuttings. In spite of the large observed difference between the cutting production of C. arabica and C. canephora, in some cases C. arabica genotypes can be obtained with rooting performance very close that observed in C. canephora.

Linalool‐rich essential oil quality variants obtained from irradiated stem nodes in Lippia alba

AbstractLippia alba cv. Kavach is a cultivar that grows perennially as a shrub for use on slopes to control soil erosion. Plants of this genotype yield several crops of leaves annually in the sub‐tropical environment, containing essential oil in about 0.2% yield. The oil contains linalool, citral and 1,8‐cineole, 64.9%, 4.8%, 1.9%, respectively. A 40 Gy and 50 Gy dose of γ‐rays caused 80% and 90% killing of single node cuttings of L. alba cv. Kavach. The 1027 regenerants obtained from 1695 irradiated cuttings demonstrated enormous variability in terpenoid profiles. They fell into 50 of 64 classes formed on the basis of concentrations of 1,8‐cineole, neral, geranial and linalool. Testing of the clone L‐601 over four cycles of vegetative multiplication showed stability of the mutated highly linalool‐rich (>80%) essential oil profile. γ‐Rays somatic mutagenesis has been found to be an effective tool for generating new essential oil profiles in L. alba cv. Kavach. Copyright © 2002 John Wiley & Sons, Ltd.

閉鎖型苗生産システムにおけるサツマイモ増殖体生産速度と消費電力量に及ぼす栽植密度の影響

Multiplication ratio (number of average of harvestable propagules per stock plant, M) and electric energy consumption per propagule (Ep) at four levels of planting density (59, 118, 236 and 473 m-2) were investigated for sweetpotato (Ipomoea batatas (L.) Lam.) vegetative propagation in a closed transplant production system. After n multiplication cycles, total number of harvestable propagules (Nn) and electric energy consumption per propagule (Ep, n) in the system were estimated by using mathematical models. Single nodal cuttings were used as propagules and grown to 14 days under photosynthetic photon flux of 140, 200 and 320μ mol·m-2·s-1 during 1 to 5, 6 to 10 and 11 to 14 days after planting, respectively. Other environmental conditions included photoperiod of 16 h·d-1, air temperature of 29°C, and CO2 concentration of 920μmol·mo1-1. At the planting densities of 59, 118, 236 and 473 m-2, M were 5.9, 6.4, 3.8 and 2.3, respectively, and Ep, 1 were 0.41, 0.19, 0.16 and 0.13 kWh (electricity cost : 6.2, 2.9, 2.4 and 2.0 Yen), respectively. Results suggest that production can be optimized and electricity cost can be reduced by manipulating planting densities.

In vitro protocols and field performance of elites of an important bamboo Dendrocalamus hamiltonii Nees et Arn. Ex Munro

Seedling raised elites of Dendrocalamus hamiltonii Nees et Arn. Ex Munro were chosen as the source of nodal explants from precocious branches. While axillary bud break was accomplished in hormone free 1/2MS medium containing sucrose (3%, w/v), BA supplementation was required for shoot proliferation. A variety of hormonal combinations induced rooting in clumps of shoots. Somatic embryogenesis was also obtained in callus cultures raised in 2,4-D supplemented MS medium and plantlets derived from somatic embryos were hardened for field transfer. Comparative growth performances of plants raised from nodal cuttings of field-grown plants, those from single node cuttings of precocious branches and from somatic embryos indicated that growth performance of the tissue culture raised plants was relatively better than those from nodal cuttings. Improved protocols for efficient micropropagation are visualized to provide an impetus to raising of bamboo nurseries of elite genotypes in bamboo growing areas of western Himalayas.

Microproagation of Fluted pumkin by Enhanced Axilary shoot formation

In a bid to develop protocols for micropropagation of fluted pumkin (Telfairia occidentalis), single node cuttings of two genotypes, Telfairia occidentalis white and Telfairia occidentalis orange (ToW-1 and ToR-1 respectively) were cultured in Murashige and Skoog medium but with four different combinations of kinetin and naphthalene acetic acid concentrations. The highest number of nodes per plantlet was obtained in the medium containing l=litre2.0mg/1 kinetin which indicates suitability for micropropagation purposes. There was however, lack of root formation. Premature senescence was also significantly predminant in ToR-1 relative to ToW1. Optimum medium for Telfairia micropropagation appears to be genotype dependent. Key Words: Telfairia, micropropagation.

Effects of air humidity and K/Ca ratio in the nutrient supply on growth and postharvest characteristics of cut roses

Single node cuttings with one mature leaf were taken from the rose cv. Baroness and rooted in water culture. The rooted plants were grown in nutrient solutions and subjected to two levels of relative air humidity (RH): high (90%) and moderate (70%), in combination with high (12/1), medium (1/1) and low (1/5) K/Ca ratios in the nutrient solution. High RH plants accumulated less Ca in leaves and flowers than moderate RH plants. Roses grown at moderate RH had a longer postharvest life than high RH roses, irrespective of the K/Ca ratio of the nutrient solution. In general, a high K/Ca ratio had a negative impact on postharvest life. When grown at a high K/Ca ratio the ornamental value declined rapidly, mainly due to the appearance of necrotic petals as well as chlorotic and necrotic areas on the leaves. Bent neck occurred only with high RH plants but changes in the K/Ca ratio had no differential effect. Dry spots and brittle leaves were observed on high RH roses, and the occurrence increased with increased K/Ca ratio in the nutrient solution. Stomatal conductance increased in parallel with increases in RH and K/Ca ratio when measured on intact roses placed in dry air (40% RH).

Combined In Vitro and In Vivo Propagation for Rapid Multiplication of Grapevine cv. Arka Neelamani

A novel combination of in vitro and in vivo approaches was employed to generate sufficient stock of an introduced grape (Vitis vinifera L.) cv. Arka Neelamani which significantly accelerated the multiplication rate. The in vitro part included induction of root and shoot growth in shoot tip and nodal microcuttings in MS medium containing 1 μm IAA, sequential pruning of shoots at 1, 1.5, and 2 months, leaving the basal one to two nodes, resulting in fresh sprouts on the stump, and use of remaining stumps for in vivo establishment. The in vivo part included acclimatization of in vitro rooted plantlets and stumps, use of single node cuttings from 1.5- to 2-month-old in vivo shoots for the subsequent propagation, and utilizing the fresh sprout growth from these cuttings and in vivo stumps for further propagation. Employing both in vitro and in vivo approaches, we achieved a multiplication rate unparalleled to the general micropropagation or conventional propagation and significant stock was obtained within 6 months of introducing the material. The in vivo plants exhibited adult characters like distichous phyllotaxy, three lobed leaves and normal pattern of tendril development within 2 months from planting.

Water loss and postharvest characteristics of cut roses grown at high or moderate relative air humidity

Single node cuttings with one mature leaf were taken from the rose cv. Baroness and rooted in water culture. The rooted stems were kept in water culture and subjected to one of the two levels of relative air humidity (RH) (high: 90%, moderate: 70%) in climate chambers. Morphological characteristics, dry weight (DW), osmotic concentration, hemicellulose, cellulose and lignin content in the pedicel and vase life behavior were studied, as well as water loss. Only negligible differences in growth and morphology were found. No clear difference in lignin, hemicellulose and cellulose content in pedicels was found between moderate and high RH grown roses. Uncontrolled water loss was characteristic for leaves from high RH roses. Base treatment with AgNO 3 improved vase life of high RH roses from 7 to 12 days. Moderate RH roses lasted on average 15.5 days, and vase life was only slightly improved with the use of AgNO 3. Preservative solutions caused crispy areas between the veins and brittle leaves on roses grown at high but not at moderate RH. A 10% lower osmotic concentration in leaves and flowers was found in roses grown at high RH, as compared to moderate RH. It is concluded that the shorter postharvest life of high RH flowers is mainly due to malfunctioning stomata.

In Vitro Rooting ofVitisSpecies Native to Texas and New Mexico

Abstract Cuttings of native grape vines were taken from Crosby County, TX, San Migel County, NM and Otero County, NM. These cuttings were cultivated in a greenhouse for a year and then propagated in vitro to evaluate the difference in rooting ability between the species. The different species evaluated were Vitis arizonica, V. treleasei and an interspecific hybrid involving V. treleasei with one or more of the following: V. acerifolia, V. arizonica, V. doaniana. Vitis vinifera ‘Cabernet Sauvignon’ and ‘Chardonnay’ were used as controls for comparison with the native species. Single-node cuttings were placed on 1/2 strength Murashige and Skoog medium and observed for 4 weeks. Cuttings from all genotypes rooted well (>73% of cuttings rooted), with the exception of one selection of V. treleasei (36%). Cuttings from a more recent collection were also propagated in vitro directly after collection from the field, although contamination rates were much higher.

MRNA localization in in vitro grown microtubers of potatoas a tool to study starch metabolism

In vitro grown microtubers were used to investigate whether in situ hybridization is a feasible technique to study expression of genes involved in starch metabolism in potato ( Solanum tuberosum L.). Single node cuttings containing an axillary bud were placed on a tuber-inducing medium. Microtubers were harvested 7 d after culture initiation, and were subsequently prepared for in situ hybridization with antisense RNA probes derived from cDNA clones encoding for sucrose synthase (EC 2.4.1.13), granule bound starch synthase (EC 2.4.1.21) and starch branching enzyme (EC 2.4.1.18). Tissue specific expression can be monitored with the use of dark field microscopy at low magnification. This technique showed that the sucrose synthase gene is expressed in the tuber, but not in the apical meristem or the stolon on which the tuber was formed. Bright field microscopy allows the visualization of mRNAs at the subcellular level. mRNAs encoding for granule bound starch synthase and starch branching enzyme were accumulating primarily around the amyloplast. In contrast, the mRNAs encoding for sucrose synthase did not show a preferential distribution. These results demonstrate the feasibility of in situ hybridization for potato tubers, and suggest an additional level of regulation in starch metabolism.

Leaf number and position effects on the survival and performance of grape microcuttings in vitro, and the sensitivity of the cut nodal region to the medium

The presence of leaf in microcuttings of grape cvs. Arka Neelamani and Thompson Seedless promoted rooting in vitro (MS, 1 μM IAA, 0.1 μM GA3, 3% sucrose) but the effect varied depending on the number of leaves and position of the leaf on the cutting. Single node cuttings with a full-length lower internode and a lamina at top (LAT) showed earlier rooting and more root and shoot growth than cuttings with lamina positioned at the middle (LAM), while cuttings with a leaf at the base (LAB) of the cutting and full-length upper internode exhibited a lower percent rooting and sprouting, poor root and shoot growth, and low survival. Partial or complete removal of the upper internodal segment in LAB cuttings improved rooting and sprouting suggesting the possible operation of an inhibitory effect by the upper internode. Retaining an upper leaf in LAB cuttings (LAB+UL) resulted in necrosis of the upper leaf often followed by the lower one. The extent of necrotic damage was influenced by the leaf area and position or age of the cutting on the stock shoot. Retaining the lower internode in LAB and LAB+UL cuttings which held the node–leaf junction away from the medium, or reducing the concentration of MS medium helped significantly in improving the survival and performance of these cuttings. The difference in reaction between LAB and LAT cuttings was attributable mainly to the difference in the sensitivity of the stem part that came in contact with the medium. Removal of the leaf in LAB cuttings reduced this sensitivity. The majority of the LAB and LAB+UL cuttings, as well as non-rooting or delayed rooting LAT and LAM cuttings, exhibited high purple pigmentation of leaf, petiole and stem. Two-leafed cuttings in vitro showed poor survival, less rooting and low plantlet output compared to single-leafed cuttings.

Photoautotrophic growth response of in vitro cultured coffee plantlets to ventilation methods and photosynthetic photon fluxes under carbon dioxide enriched condition

Effects of two ventilation methods (forced and natural) and two photosynthetic photon fluxes (PPF, 150 and 250 μmol m−2 s−1) on the photoautotrophic growth of in vitro cultured coffee (Coffea arabusta) plantlets were investigated. Number of air exchanges was 2.7, 5.9 and 3.9 h−1 for forced low rate, forced high rate and natural ventilation, respectively. Single node cuttings of in vitro cultured coffee plantlets were cultured on Florialite, a mixture of vermiculite and cellulose fibers with high air porosity, emerged in liquid half strength basal MS medium, without sucrose, vitamins and plant growth regulators. The study included 40 days in the in vitro stage and 10 days in the ex vitro stage. Mean fresh and dry weights, leaf area, shoot and root lengths and net photosynthetic rate per plantlet were significantly greater in forced high rate treatments compared with those in natural and forced low rate treatments. PPF had a distinct effect on shoot length suppression and root elongation of coffee plantlets in forced high rate treatments. The control of carbon dioxide concentration inside the culture box according to the plant demand when growing was easy with the forced ventilation method in photoautotrophic micropropagation.

610 Growth and Cutting Production Rates of Sweetpotato as Affected by CO2 Concentration

For vegetative propagation of sweetpotato, single or multi-node leafy cuttings are used as propagules. A quantitative understanding of leaf development is important for predicting the number of propagules produced after a given production period under various environmental conditions. For plant production in a relatively closed structure, controlling CO2 concentration is necessary, but effects of CO2 concentration on cutting production rates of sweetpotato are not well-investigated. Single-node cuttings each with a fully expanded leaf (the initial leaf blade length was 66 mm) were grown under one of three levels of CO2 concentration (400, 800, and 1200 μmol·mol-1), 250 μmol·m-2·s-1 PPF, 16 h/day photoperiod, and 29 °C air temperature. The plant dry weight increased faster in the higher CO2 concentrations. Changes in the number of harvestable cuttings during the production period was defined by changes in the number of leaves reaching a leaf blade length (LBL) longer than a given standard length (LS). The number of harvestable cuttings increased almost linearly with time after the LBL of the first leaf reached the LS, regardless of CO2 concentration. The effect of CO2 concentration on cutting production rate (number of harvestable cuttings per day) was varied with different LS. For example, at LS = 20, 30, and 40 mm, the cutting production rate increased slightly at higher CO2 concentrations, while at LS = 60 mm, it decreased significantly at higher CO2 concentrations. This indicates that, under the present experimental conditions, increasing CO2 concentration increased the number of small leaves that might not be usable as cuttings (propagules). Environmental control is necessary in vegetative propagation to increase the number of propagules and the biomass usable as propagules, thereby minimizing energy and resources needed for the propagule/transplant production process.

Slow-growth storage of single node shoots of apple genotypes

A landrace (‘Moscatella’) and a commercial cultivar (‘Starkspur Red’) of Malus pumila Mill. were maintained and proliferated in vitro for ≥ four years. A factorial experiment, planned to evaluate the response of the two cultivars in conservation in determined slow growth conditions, was carried out for eighteen months. Single node cuttings were stored in 4 different media, at 4 °C, in dark conditions, in microvessels to assess the feasibility of reducing space in in vitro gemplasm banks. Culture viability after storage was evaluated after 6, 8,12 and 18 months of storage. Both varieties showed high survival percentages for up to a year of conservation, but the landrace's capability to resume growth dropped dramatically afterwards. On the contrary, ‘Starkspur Red’ maintained substantially unchanged capacity of resuming vigorous growth after 18 months of conservation. Overall, microvessels appeared to be suitable for storing single node cuttings under slow growth conditions up to a year at least. The described techniques could be useful for in vitro germplasm collections where frequent subculturing enhances the risk of genetic changes and personnel, energy and materials costs limit the amount of genotypes that can be managed.

Field and in vitro methods of propagation of the African locust bean tree (Parkia biglobosa (Jacq.) (Benth.)

SummaryStem cutting in non-mist propagators, air layering and in vitro propagation were investigated as means of vegetative propagation of Parkia biglobosa. The results of the non-mist propagation experiment show that it is possible to root single-node stem cuttings from juvenile P. biglobosa plants in non-mist propagators. The highest percentage of rooting (35%) was achieved by the application of 1000 g m±3 IBA and NAA. Propagation of single-node stem cuttings from mature trees was, however, not a success. The results from the air layering experiment indicate that it is also possible to propagate P. biglobosa by air layering. The application of hormone (200 g m±3 IBA and NAA) produced the highest percentage of rooting of air layers (16%). The results of the in vitro propagation experiment reveal that the method offers an alternative opportunity for rapid multiplication of the tree. MS medium supplemented with 6.mg.l±1 IAA was the best for shoot initiation (81.7%) whereas 4±5 mg l±1 IAA gave the highest percentage of explants with roots (8.3%). Root promotion did not correspond well with IBA in both MS and WPM media. Transplanted in vitro rooted shoots were well acclimatized in the greenhouse and all plantlets exhibited some mature characteristics including compound leaves and multiple roots.

Microcutting leaf area, weight and position on the stock shoot influence root vigour, shoot growth and incidence of shoot tip necrosis in grape plantlets in vitro.

The physiological parameters of microcuttings, namely leaf area, weight (wt) and position on the stock shoot, had significant effects on root vigour, microshoot growth and incidence of shoot tip necrosis (STN) in cultures of grape (Vitis vinifera L.) ‘Arka Neelamani’. Single-node leafy cuttings cultured in MS medium containing 1 μM IAA and 0.1 μM GA3 generally rooted first and subsequently sprouted into a single shoot. Small leafed cuttings exhibited slow root emergence, poor quality roots, early sprouting and weak shoot growth. Large leafed cuttings on the other hand, showed early rooting, vigorous roots, delayed sprouting and healthier shoots. Significant correlations were observed between fresh root wt per plantlet at 1 month in culture and wt of lamina, total wt and leaf area of the cuttings in that order. A significant correlation also existed between wt of roots and height or wt of the sprout that developed. The study suggests that the weight or area of the leaf governed the root growth in a microcutting. STN was observed in some plantlets particularly those derived from large leafed cuttings. Such cuttings showed vigorous roots and delayed but fast sprout growth that ended in STN. Plantlets showing STN had less Ca++ and Mg++ in the shoot tissue than in the shoots of normal plantlets while the roots showed similar Ca++ or higher Mg++ contents. Both had comparable amounts of cytokinins in shoot and root tissues.

Effect of indole-3-acetic acid and kinetin on tuberisation parameters of different cultivars and transgenic lines of potato in vitro

The effect of indole-3-acetic acid or kinetin on the weight and numberof microtubers formed was studied on single node cuttings of sevendifferent potato (Solanum tuberosum L.) cultivars as well astransgenic lines harbouring rolB or rolC genes undercontrol of the patatin class I (B33) promoter. Plants were cultivatedin vitro in the dark on solidified MS medium containing 1 to8% sucrose with or without phytohormones. Most of thenontransformed potato cultivars and transgenic lines responded tohormone application by an increase in tuber yield. Auxin and cytokininacted differently: IAA increased predominantly the tuber size whilekinetin increased the number of tubers. RolC transformantsdisplayed an altered response to sucrose and especially to auxin. Thedegree of phytohormone effect on tuberisation parameters depended onsucrose content of the medium and potato genotype.

Supporting material affects the growth and development of in vitro sweet potato plantlets cultured photoautotrophically

A comparative study was conducted to optimize the vegetative growth of sweet potato (Ipomoea batatas L. (Lam), cv. Beniazuma) plantlets cultured in vitro in five different types of supporting materials: agar matrix (a seaweed derivative; Kanto Chemical Co. Inc., Tokyo), gellan gum (a Pseudomonas derivative; Kanto Chemical Co. Inc., Tokyo), vermiculite (a kind of hydrous silicates), a mixture of vermiculite and cellulose fiber (Florialite; Nisshinbo Industries, Inc., Tokyo) and cellulose plug (Sorbarod; Baumgartner Rapiers SA., Switzerland). Single nodal cuttings were cultured photoautotrophically (without any sugar in the medium and with enriched CO2 and high photosynthetic photon flux) for 21 d on MS basal medium. Plantlets exhibited the greatest growth when Florialite was used as supporting material. The leaf and root fresh and dry mass were 2.4× and 2.9×, and 2.2× and 2.8× greater, respectively, than those of the plantlets grown in the agar matrix (control). Plantlets cultured in Sorbarod supporting material exhibited the second greatest fresh and dry mass of leaves and roots followed by vermiculite and gellan gum supporting material. The most interesting feature was the development of a large number of fine lateral roots from the main adventitious root in the Florialite treatment. Among the treatments, the highest net photosynthetic rate was evident in the Florialite grown plantlets. The percent porosity of the supporting materials was highest in Sorbarod followed by Florialite and vermiculite. Plantlets transplanted from the Florialite supporting material exhibited the highest acclimatization percentage followed by that of the Sorbarod treatment.

Factors Intrinsic to the Axillary Bud Determine Topophysic Effects on Bud and Shoot Growth and Flower Development inRosa hybrida

Topophysis (the influence of the position of axillary buds along the shoot on bud and shoot growth, fresh biomass accumulation, and flower development) were studied in Rosa hybrida L. Single-node cuttings with five-leaflet leaves were excised from nine stem positions and grown as single-stemmed rose plants. Plants were grown at 20-h photoperiods, 22 degrees C average air temperature, and an average photosynthetic photon flux density of 228 µmol m-2 s-1. Generally, onset of axillary bud growth and initial shoot growth were promoted, and flower height and bloom quality were reduced in plants from apical bud positions. Stem diameter, stem growth rate, and biomass buildup were greatest from medial bud positions; the plastochron was greater, and stems and internodes were longer, from basal bud positions. Flower diameter and cut flower vase life were not significantly influenced by topophysis. The results demonstrate that topophysis can determine the potential for plant development and flowering in R. hybrida and that this knowledge may be used to regulate plant growth. Results also indicate intrinsic mechanisms determining axillary bud growth, but the physiology of topophysis is presently unclear. A probable role of cytokinins in the topophysic prevention of growth observed is discussed.

505 Analysis of Leaf Development Rates as Affected by Environment Conditions for Modeling Vegetative Propagation of Sweetpotato

For vegetative propagation of sweetpotato, single or multi-node leafy cuttings are used as propagules. A quantitative understanding of leaf development and the effects of environment conditions on leaf emergence and expansion rates is important for predicting the number of propagules produced after a given production period. Single-node cuttings each with a fully expanded leaf were grown under two levels of photosynthetic photon flux (PPF, 160 and 250 μmol·m–2·s–1) and photoperiod (10 and 16 h/day). The time courses of the number of leaves larger than the standard leaf area (As) were obtained by analyzing the time courses of leaf blade length recorded every day on each leaf. The number of leaves larger than a given As increased almost linearly after the first leaf reached to the As. PPF and photoperiod affected both the duration until the appearance of the first leaf with As and the leaf development rates (leaves per day). The effects of PPF were more pronounced than photoperiod for the development rate of the leaves regardless of As. Results obtained in these experiments were incorporated into our previously developed model, and the number of propagules produced under different environment conditions was predicted. Such techniques need to be used effectively for planning and environment control of vegetative propagation.