Rooting and initial establishment of stem cuttings of oregano,peppermint and balm

Stem cuttings of 3 Labiatae spices, oregano (Origanum vulgare L.), peppermint (Mentha piperita L.) and balm (Melissa offinicalis L.) were analyzed for their rooting- patterns and initial establishment under controlled conditions.Approximately 100% of cuttings from all 3 species rooted, but the number of roots per cutting varied in the order: oregano > balm > peppermint. Treatment of cuttings with IBA, IAA and Hormex increased both the number of roots per cutting and the rate of root formation in all 3 species. This effect was, however, dependent on their natural capacity for root formation, with the greatest effect on the slowest root producer, balm, where root number increased 3-fold.Enhanced root formation was reflected in increased fresh-weight accumulation by both root and shoot systems. Hormone treatment also increased shoot length of peppermint. All the above mentioned effects were concentration-dependent. Thus, hormonal treatment of cuttings of these 3 Labiatae spices clearly aided early establishment, and especially so in cuttings which were initially less vigorous.     

Effect of light,temperature and CO2 on the growth of Campanula isophylla stock plants and on the subsequent growth and development of their cuttings

Stock plants of Campanula isophylla Moretti were subjected to different temperature and light conditions and to various CO₂ regimes. The number and the fresh and dry weight of the cuttings produced were recorded. The after-effect of stock-plant treatment on root formation and growth of cuttings was studied.Increasing light intensity and CO₂ supply strongly promoted cutting production and increased both fresh and dry weight of the cuttings. These factors also markedly influenced root formation and root growth of the cuttings. Stock plant conditions also strongly influenced the growth and lateral shoot formation of the rooted cuttings. It is concluded that cuttings from stock plants grown under favourable light (10 Klx) and CO₂ conditions (900 v.p.m.) contain factors beneficial for root formation, growth and shoot formation. The results are discussed in relation to the carbohydrate content of the cuttings.     

Effects of time of collection,growing-conditions of mother plants and growth regulators on rooting of cuttings of Telopea speciosissima (Proteaceae)

Terminal stem cuttings of Telopea speciosissima were collected from two locations at monthly intervals and treated with indolebutyric acid (IBA) in combination with benomyl. Cuttings taken in the first half of spring, at the beginning of vegetative growth, gave the highest percentage of rooted cuttings and the greatest length of adventitious roots per rooted cutting. Cuttings taken from the environment most suited for the growth of the mother plants also produced the highest percentage of rooted cuttings, but their root length did not differ significantly between the two locations. Pre-treatment of cuttings with 4000 p.p.m. IBA (concentrated solution dip method) initially gave the highest percentage of rooted cuttings and longest root length, but there was evidence for a delayed toxicity to IBA applied at this level. Pre-treatment with 2000 p.p.m. IBA is therefore recommended.Benomyl increased the percentage of rooted cuttings, but did not affect root length, possibly due to its fungicidal rather than cytokinin activity.     

Rooting of Berberis and Ligustrum cuttings from stock plants grown at selected light intensities

Plants of Berberis thunbergii DC., B. thunbergii DC, ‘Atropurpurea’, Ligustrum obtusifolium Seibold and Zucc. var. regelianum (Koehne) Rehd., and L. × vicaryi Beckett were grown at 37, 53, 70 and 100% full sunlight to determine rootability of cuttings. Rooting hormone levels of 0, 0.1, 0.3 and 0.8% IBA in talc were applied to the cuttings, and % rooting, root length, and fresh and dry weights were recorded. Optimum rooting of cuttings of Berberis resulted when stock plants were grown at 70% light, with 37% light being the next most successful. Optimum rooting of cuttings of Ligustrum obtusifolium var. regelianum resulted when stock plants were grown at 37% light. Rooting of Ligustrum × vicaryi did not respond to light intensity. An interaction between rooting-hormone and light intensity was noted for root length of Ligustrum species.     

Nitrogen content determines adventitious rooting in Euphorbia pulcherrima under adequate light independently of pre-rooting carbohydrate depletion of cuttings

Root regeneration in shoot tip cuttings responds to graduated nitrogen (N) fertilization of stock plants. In pelargonium cuttings, reduced carbohydrate reserves caused by high N absorption by the donor plants and post-harvest storage of cuttings limit adventitious root formation, especially in low-light environments. In contrast, in chrysanthemum, similar carbohydrate reserves do not have this dominant effect on rooting capacity. The positive correlation between rooting capacity and internal N status is stable across a wide range of environments and is genotypically consistent for this species. However, the influence of N and carbohydrates on adventitious rooting of Euphorbia pulcherrima is unknown. We investigated the consequences of different N fertilization regimens applied to E. pulcherrima stock plants and cold and dark storage of the cuttings on N absorption, carbohydrate distribution, and rooting capacity of cuttings. Increasing time of stock plant cultivation with graduated N nutrition produced cuttings with N contents, ranging from 19 to 51 mg N g⁻¹ dry mass (DM). High N absorption resulted in low carbohydrate concentrations in cuttings, and subsequent storage decreased carbohydrate concentrations further, particularly in stems. Lower sucrose contents in leaves were correlated with reduced rooting of stored cuttings at a particular harvest date. However, despite the lower carbohydrate levels, root numbers and lengths correlated positively with internal N concentrations. These relationships remained stable in unstored and stored cuttings, even when overall rooting intensity was reduced under lower natural light during autumn. Multivariate regressions accounting for nitrogen content, sucrose content and daily light integral during rooting highlighted these relationships and explained up to 79% of rooting variances. We conclude N nutrition of stock plants and N absorption by cuttings are the dominant factors determining the rooting capacity of poinsettia when rooting occurs under sufficient light, as is commonly available during propagation. To maximize rooting capacity of poinsettia cuttings their nitrogen content should exceed a threshold of 40 mg N g⁻¹ DM.     

Effect of indolebutyric acid and sampling-dates on the rooting of four Tilia taxa

Softwood and semi-hardwood cuttings of 4 Tilia taxa were taken at different times and treated with high concentrations of IBA. Rooting-response varied with taxa and sampling-date. Rooting in Tilia americana L. cuttings was maximum when taken on 19 May and 1 June. Cuttings of Tilia cordata Mill. did not differ significantly in rootability when taken on 19 May, 22 June or 13 July, but rooting was significantly less with 3 August cuttings. Tilia × euchlora Koch cuttings did not root. All Tilla × euchlora Koch ‘Redmond’ cuttings taken on 19 May or 22 June rooted. A 5-second basal dip of IBA significantly stimulated rooting, especially in the range of 20 000–35 000 mg 1^?1.     

Contributions of the stem to rooting in Eucalyptus grandis Hill ex Maid,stem cuttings

An additional wound at the base of one-node stem cuttings of Eucalyptus grandis increased rooting. Girdling intact shoots reduced rooting in cuttings harvested from them, while girdling cuttings at setting had little effect, suggesting that the internal phloem was active in basipetal transport in the stem. The vertical distribution of roots in additionally wounded cuttings also suggested a changed pattern of efflux from the internal phloem, as well as an increase in water uptake. In one-leaf cuttings more roots emerged from the leaf trace sector of the stem than from the trace of the absent leaf. In two-leaf cuttings the circumferential distribution of roots was uniform except in cuttings (a) reduced to a half-round cross-section at the base, in which rooting was more profuse at the lower of two sites of root emergence, and (b) from lateral coppice shoots whose stems were red-pigmented above with anthocyanins, in which there was less rooting than expected in the red sector. Stem volume was well related to rooting ability, largely explaining variation due to the original position of the cutting within the shoot and crown.     

Root development of Thuja plicata in peat-substitute rooting media

In this study we investigated the potential usefulness of different substrates produced from gorse (Ulex europaeus L.) for propagating cuttings of Thuja plicata ‘Atrovirens’. The gorse was composted by different methods, to produce four types of compost. These composts were then used as such (100% compost) or in mixes with coarse sand and pine bark compost (25% compost, 25% coarse sand and 50% pine bark compost, v/v/v) to prepare eight different substrates. The substrates were compared in cutting propagation trials carried out in a greenhouse, with a standard rooting medium consisting of 25% Sphagnum peat moss, 25% coarse sand and 50% pine bark compost (v/v/v). Cuttings were taken from a garden hedge in March 2003, and comprised shoots of the previous year's growth. The bases of the cuttings were treated with a 0.4% solution of IBA rooting hormone, then inserted into cells filled with the corresponding substrate and placed on a propagation bench. Rooting percentage and visual rooting score were determined in July. The quality of roots was evaluated, as total root length and number of root tips, in July, September and November 2003, by use of a Delta-T Scan system. The rooting success of the cuttings ranged from 75% to 90%, except when the substrate comprised the pure composted gorse, obtained after the shorter period in an enclosed composting system with addition of fertilizer and reuse of leachates. Most of the cuttings in this substrate died and only 4% of the cuttings rooted successfully. Physicochemical characteristics of this rooting medium included very high electrical conductivity, low C/N ratio and high water retention. Addition of coarse sand and pine bark compost to the composted gorse significantly increased the rooting success. The root quality variables differed depending on the substrate considered and date of harvest. The results showed that substrates made from gorse compost are of potential use as a peat substitute for propagating cuttings of T. plicata ‘Atrovirens’. The physicochemical properties of the composted gorse should be determined before its use to establish whether it can be used pure as a substrate for rooting or whether it should be mixed with other substances.     

The concept of a limiting rooting morphogen in woody stem cuttings

SUMMARY

A rooting morphogen, arbitrarily defined, can be assumed to induce adventitious roots in woody stem cuttings. Auxins generally promote rooting in herbaceous cuttings and are often considered to limit rooting, but they often have little or noeffect when applied to difficult-to-root woody cuttings. They can move in a polar (basipetal) pathway but the polarity of root emergence equally reflects the activity of the vascular system in general, including the phloem, whose contents have a complex composition. The interactions between a morphogen of vascular origin and potential sites for root initiation arelikely to be dynamic and variables such as flux rate or flux direction could be more relevant than static variables such as composition or concentration. The potential sites are not equally sensitive to the rooting morphogen since each cell hasa unique lineage, ontogeny and position, and a prevailing insensitivity could restrict rooting. The contents of the vascular system are inaccessible to potential sites in the stem, so factors affecting efflux and the subsequent attenuation of the efflux, which depend on activity in the whole cutting, could be critical to rooting ability. No simply defined morphogen can be said to limit rooting, and the chemical identity of the morphogen (if definable) is probably unimportant.     

Propagation of Plants by Root Cuttings: II. Seasonal Fluctuation of Capacity to Regenerate from Roots

Some species regenerate readily from root cuttings at any time of year, whereas cuttings of other species show a well-marked seasonal fluctuation in capacity to grow. In the latter a high proportion of successes is possible only if cuttings are taken in the “ on ” season. In the “ off ” season for raspberry, not only do root cuttings fail but whole root systems, severed and left undisturbed in situ, also die. The regenerative capacity of (a) root cuttings, and (b) severed roots left in situ, has a bearing on the degree of control, which can be obtained by tillage, of weed species which are able to regenerate from roots left in the ground.     

Piriformospora indica promotes adventitious root formation in cuttings

Adventitious root formation in excised plant shoots is a crucial process in the vegetative propagation of many plant species, and insufficient rooting causes substantial losses in the propagation industry. Based on the various physiological effects on whole plants described for the basidiomycete Piriformospora indica, it was hypothesized that inoculation of the substrate with this endophyte should promote the generation and growth of adventitious roots in cuttings. Inoculation experiments were conducted to study the effects of P. indica on adventitious rooting in three plant species. Inoculation with P. indica dramatically enhanced the number and length of the adventitious roots in pelargonium and poinsettia. Root colonization parameters suggest that the interaction between the endophyte and cuttings had already occurred before physical contact. In contrast, petunia showed no rooting response to P. indica inoculation. Very fast root formation in this plant indicates that a minimum time period for the fungus–plant interaction is required for establishment of a promoting effect. P. indica-based biotechnology is proposed as a new tool for improving plant propagation systems of plant species or cultivars with low to moderate capacity of adventitious root formation.     

Induction of roots on jujube softwood cuttings using Agrobacterium rhizogenes

Summary

Cuttings from trees of jujube (Ziziphus jujuba Mill.), particularly mature ones, root with great difficulty. A greenhouse experiment assessed the effects of two strains of Agrobacterium rhizogenes (A4 and TR105) on softwood cuttings from two sources: ten year old trees of cv. Li and a tree approximately 40 years old of the cv. Contorta. The cuttings were collected and trimmed to 7.5 cm. Ten weeks after inoculation, both strain and source of cutting influenced visible symptoms of infection. Jujube cuttings were more responsive to TR105 than to A4, and the ‘Li’ cuttings were more responsive than ‘Contorta’ cuttings. Strain TR105 was very effective in increasing rooting percentages and root number. ‘Li’ cuttings had better rooting percentages, greater root number, and greater root length than did the ‘Contorta’ cuttings. Inoculation with A. rhizogenes may also possess great potential for promoting adventitious root formation in other difficult woody ornamental or fruit tree species.     

Effect of auxin treatments,cuttings’ collection date and initial characteristics on Paeonia ‘Yang Fei Chu Yu’ cutting propagation

Paeonia ‘Yang Fei Chu Yu’ is one of the most popular and commercially valuable cultivars of herbaceous peony. The study was performed to explore propagation techniques by cuttings for the nursery industry. Results showed that the stem cuttings pretreated with 2000 mg L⁻¹ indole-3-butyric acid (IBA) in quick-dip method got the best rooting traits (rooting percentage is 86.7%, root number is 23.1 and root length per rooted cutting is 6.4 cm). Therefore pre-treatment with 2000 mg L⁻¹ IBA is recommended.     

Rooting of chrysanthemum cuttings. Influence of irradiance during stock plant growth and of decapitation and disbudding of cuttings

Stock plants of Chrysanthemum morifolium Ramat. cultivar ‘Improved Mefo’ were grown in a controlled-environment room at different levels of irradiance (9, 23, 53 or 90 W m^?2). After 3 weeks, cuttings were excised and rooted for 3 weeks at an irradiance of 16 W m^?2. Cuttings from stock plants grown at the highest irradiance had the highest number of roots, while cuttings from the lowest irradiance had the lowest number of roots.The importance of the presence of shoot meristems for root formation was investigated through disbudding and decapitation at different times after the excision of the cuttings. Removing the buds on the day of excision had no effect on the number of roots formed, while the removal of the buds on day 2 to day 5 after excision had a promotive effect. Removal later than 7 days after excision had no effect at all.The results are discussed from the point of view that an interaction between nutritional and hormonal factors regulates the process of root formation.     

Micropropagation of red raspberry

A method for the rapid propagation of raspberry (Rubus idaeus cultivar ‘Heritage’) is described, involving tip-culture, shoot elongation, multiplication by small cuttings, root initiation and transfer of plants to soil.     

Vegetative propagation of carnation in vitro through multiple shoot development

Vegetative shoot cuttings of 6 cultivars of carnation (Dianthus caryophyllus L.) were irradiated with 30 or 60 Gy X-rays. Subsequently, from both control and irradiated cuttings, explants were excised at 2 positions of the stem and cultured in vitro. The effects of X-ray dose, genotype and explant position on multiple shoot development of in vitro-cultured nodal stem explants, and on root formation of sub-cultured shoots, were examined. The in vitro propagation method resulted in the production of 2220 plantlets from 209 explants, 4 months after incubation.     

Water transport through the roots of ornamental shrub cuttings

Summary

The use of leafy cuttings to propagate ornamental shrubs such as Corylus maxima cv. Purpurea is often hampered by “weaning” problems. These arise when the rooted cuttings are removed from the supportive environment designed to promote rooting and are transferred to a more natural, but relatively stressful, environment. The shrivelling of leaves which ensues points to some failure of normal plant water relations, which may be caused either by excessive water loss from the leaves, or an inadequate water supply from the roots, or a combination of these factors. To understand this problem more fully, the root hydraulic conductance of C. maxima cv. Purpurea cuttings was investigated, and compared with that of Weigela florida cv. Variegata, a shrub which does not exhibit weaning problems. The root hydraulic conductance for both species increased with the size of the root system, and root fresh weight was shown to provide a useful basis for relative measurements of root conductance. On this basis, cuttings of W. florida exhibited a higher root hydraulic conductance than comparable C. maxima cuttings (1.5 × 10^?4 and 9.7 × 10^?5 g s^?1 MPa^?1 g_root^?1 respectively), but the difference was not sufficiently large to account for the differences in weaning of these two species. It is suggested that the adventitious root system of C. maxima is functioning normally, but that it cannot supply enough water to balance uncontrolled water loss from the leaves.     

Effect of leaf retention and flavonoids on rooting of Ilex paraguariensis cuttings

The effect of the mature leaf retention and the exogenous application of flavonoids (naringenin, quercetin and rutin at 30 μM for 12 h) was studied for adventitious rooting of Ilex paraguariensis cuttings. Softwood cuttings harvested from young 3-year-old plants and adult 10- and 20-year-old plants were rooted under intermittent fog. A strong correlation (r² = 0.72) between leaf retention and rooting was noted. The highest percentage of adventitious root formation (40%) was obtained when the leaf was artificially removed after 42 days of incubation. This data was supported by the histological analysis which provided anatomical evidence that cuttings have initiated root primordia by 21 days and the regenerated roots emerge through the epidermis after 35 days of incubation. A strong correlation between the position of the leaf and the site of roots regeneration was observed. A 100% of the rooted cutting with a single leaf only formed roots along the leaf axis at the base of the cutting. Quercetin increased the rooting percentage more than three times compared to the control and all flavonoids tested improved the distribution of roots around the stem without impacting the number of regenerated roots per rooted cutting from 20-year-old plants.     

巨峰实生葡萄阶段发育过程中繁殖生理的研究

以3年生巨峰葡萄实生苗为材料,分析了实生苗不同阶段部位的枝条和不同级别的根段扦插生根能力、不同阶段枝条上侧芽脱分化形成愈伤组织能力及愈伤组织生长速度的差异。结果表明:巨峰葡萄实生苗不同节位枝条及不同级别根段扦插繁殖,其生根数、根长、根重与节位及粗度存在二元回归关系。枝条扦插生根数与其节位的回归(b=-0.37)达显著水平。根段扦插的生根数、根重与其根段的级别的回归(b_1=0.20,b_2=0.01)分别达到极显著和显著水平。低节位枝条的侧芽易脱分化形成愈伤组织,所形成的愈伤组织有较快的增长速度。巨峰实生葡萄的阶段性变化具有连续性。     

Flowering influences adventitious root formation in chrysanthemum cuttings

Root formation in chrysanthemum (Dendranthemum grandiflora (Ramat.) Kitamura) cuttings was reduced as flowers developed on stock plants. This effect was shown for all ten cultivars evaluated in this study. Not all cultivars were affected equally by the presence of flower buds on cuttings. There was no relationship (r² = 0.06) between root formation in vegetative cuttings and the ability for a cultivar to root from flowering cuttings. IBA (1 mM) could partially overcome the negative effect of flowering on root formation, but cuttings taken after the flower buds had fully opened failed to root even after auxin treatment. Removing buds from cuttings or continually removing flower buds during stock plant growth reduced rooting compared to cuttings with flower buds intact. Furthermore, cuttings taken from the top three nodes of the stock plant containing flower buds rooted comparably to cuttings taken from the lower stem section that contained only vegetative buds. The negative influence of flowering on root formation appears to be due to the photoperiodic induction of the flowering stimulus rather than a direct competition for resources between flowers and developing roots.