Adventitious root formation of Japanese cedar (Cryptomeria japonica D. Don) cuttings is stimulated by soaking basal portion of cuttings in warmed water while cooling their apical portion

To improve the propagation of Japanese cedar (Cryptomeria japonica D. Don), we investigated the effects of apical and basal temperatures during a water soaking treatment on the adventitious root formation of 70-mm long shoot tip cuttings which have an apical bud. The basal portion of the cuttings was soaked for 28 days in water with temperatures ranging from 10 to 35 °C, at an air temperature of 5 or 10 °C. Control cuttings were soaked in water at 25 °C, with an air temperature of 25 °C. Treated cuttings were then planted in vermiculite rooting medium and grown at an air temperature of 25 °C for 35 days. Adventitious roots initiated earlier and developed more in the cuttings treated with apical temperatures of 5 or 10 °C and basal temperatures of 20–30 °C than in the control cuttings. The rooting percentage was greatest (93 %) in the cuttings treated with a 10/25 °C apical/basal temperature, whereas few control cuttings rooted (13 %). This suggests that the temperature gradient created by warming the basal portion of the cuttings while cooling their apical end stimulates adventitious root formation. When we tested seasonal variation of rootability at 10/25 °C, the rooting percentage increased from early autumn to winter, and decreased from winter to summer. The soluble sugar contents did not directly affect the formation of adventitious roots in the present study.     

A comparison of pre-planting treatments on hardwood cuttings of four hybrid poplar clones

Rooting and early growth of four hybrid poplar clones (Populus spp.) planted in a greenhouse were examined after applying 40 pre-rooting treatment combinations to dormant cuttings. Treatments included 2 cutting lengths (5 and 10 cm), 5 soaking times (0, 2, 4, 8, and 12 days), and 4 dips (chitosan, rooting hormone powder, liquid rooting hormone added to the soaking water, and none). Significant differences in both rooting percentages and growth were shown between clones after 7 weeks of growth. Ten cm cuttings had 29% greater rooting success, 28% more above-ground growth, and 12% lower root/shoot ratios than 5 cm cuttings. Cuttings planted without soaking had the lowest rooting success, at less than 45% on average. Commercial rooting hormones decreased the number of rooted cuttings but increased root/shoot ratios. For optimal rooting, we recommend using 10 cm cuttings, soaked for 2 days in water (4 days for the Jackii10 clone) without any additional dipping/hormone substance.     

Relationship of water to adventitious rooting in stem cuttings of Populus species

Populus species, characterized by fast growth and easy vegetative propagation, are widely used in agroforestry practices. The substantial water requirement of poplars make them interesting subjects for water balance studies. No information exists on soil moisture requirements for initial root and shoot growth of Populus cuttings. This study on leafless hardwood cuttings of Populus x euramericana (Dode) Guinier cv. Robusta examined the dynamics of water use during propagation, as influenced by two initial soil water potentials (–0.006 and –0.06 MPa). Differences in the initial water potential of the cuttings was achieved by three pretreatments i.e., fresh, soaked and dried. Initial _shoot was –1.45, –0.10 and –2.10 MPa in fresh, soaked and dried cuttings, respectively. Soil moisture had a major effect on rooting. Water-stressed cuttings took a longer time to root and had fewer roots. Pre-soaking of cuttings stimulated rooting, particularly under the drier soil moisture conditions. Initially the water potential of cuttings decreased with time and with the formation of roots it stabilized in all the pretreatments. The reduction in water potential of cuttings after planting was related to an increase in resistance to water flow in the xylem.This revised version was published online in November 2005 with corrections to the Cover Date.     

Vegetative propagation of Colutea istria Mill. from leafy stem cuttings

This study investigates the optimal conditions for the vegetative propagation of the multipurpose leguminous shrub Colutea istria from leafy stem cuttings. The conditions examined included 1) the origin of the cutting (apical, medial or basal), 2) indole-3-butyric acid (IBA) treatment (0, 50, 200 or 400 mg/l), 3) the relative humidity of the propagation environment (high or low), 4) wounding base of cutting, and 5) the season in which the cutting was taken. The rooting ability of the cuttings was significantly influenced by all these factors. Winter cuttings obtained from the middle and base of the branch showed a greater rooting capacity than those harvested from the apical area, while autumn cuttings harvested from the middle and apical areas of the branch showed a greater rooting capacity than those harvested from the base. Winter cuttings showed the best rooting capacity than autumn cuttings. IBA treatment (200 mg/l), high humidity (98-100%), and wounding increased the rooting capacity of the cuttings. The sprout of new leaves was higher in basal cuttings, while IBA and wounding also significantly enhanced the root number of rooted cuttings. A method for vegetatively propagating C. istria plants is given.     

杨树新无性系扦插生根特性的研究

以杨树新无性系ＮＬ－８０１０６、ＮＬ－８０１２１和ＮＬ－８０３５１为材料，从解剖学角度研究其插插生根的机理。结果表明，无性系ＮＬ－８０１０６的生根能力较ＮＬ－８０３５１强；插穗的不定根原基在母株生长早期形成，起源于射线与形成层交叉处；不定根原基的数量随着苗高的增长而增多；但插穗的生根能力与不定根原基的数量关系不大。     

Vegetative propagation of Colutea arborescens L., a multipurpose leguminous shrub of semiarid climates

The vegetative propagation of the multipurpose leguminous shrub Colutea arborescens from leafless hardwood cuttings was examined. Specific attention was paid to the factors: 1) cutting origin (apical, medial or basal); 2) indole-3-butyric acid (IBA) treatment (0, 50 or 200 ppm); and 3) relative humidity of the propagation environment (high or low humidity). After 120 days, 67.6% of the C. arborescens cuttings had rooted. The rooting ability of the cuttings was significantly influenced by the cutting origin and hormonal treatment. No effects on rooting percentage were shown by the relative humidity of the propagation environment. The best rooting response (95%) was shown by basal cuttings treated with 200 ppm IBA. Cutting origin, IBA treatment and relative humidity were significantly related to the root number, longest root length and the fresh/dry biomass of roots and leaves. Under conditions of high humidity, basal cuttings treated with 200 ppm IBA gave rise to the most highly developed plants. The positive relationship between sprouting and rooting suggests that successful propagation is related to the shoot formation potential of the cutting's food reserves. These findings were used to propose an efficient method for the vegetative propagation of C. arborescens plants. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effect of soil and plant water relations on rooting of Populus × euramericana stem cuttings

Studies on Populus ×euramericana (Dode) Guinier cv. Robusta wereconducted to examine the rooting behaviour and changes in water potentialduringrooting, as influenced by the initial water potential of the cutting at twosoilwater potentials (–0.006 and –0.06 MPa). Differencesinthe initial water potential of the cuttings was achieved by three pretreatmentsi.e., fresh, soaked and dried. Initial _shoot was –1.45,–0.10 and –2.10 MPa in fresh, soaked and driedcuttings, respectively. Soil moisture had a major effect on rooting. Waterstressed cuttings took a longer time to root and had fewer roots. Pre-soakingofcuttings stimulated rooting particularly under the drier soil moistureconditions. Initially the water potential of cuttings decreased with time andwith the formation of roots it stabilized in all the pretreatments.Resistance-to-flow measurements suggested the development of tyloses and theestablishment of new xylem. No relationship was evident between stomatalresistance of leaves and water potential of cuttings. The starch content of thestem cuttings decreased significantly with time irrespective of treatment.     

Vegetative propagation of African Mahogany: effects of auxin, node position, leaf area and cutting length

Applied auxin, node position, leaf area and cutting length were examined to investigate the requirements for rooting stem cuttings of Khaya ivorensis. All these variables were shown to be important factors affecting rooting, confirming the hypothesis that successful rooting can be achieved if these primary variables are optimised.The best concentration of the auxin IBA was found to be 200 g per cutting, which hastened rooting, increased the percentage of cuttings rooted and increased the number of roots per cutting. One clone (8013) was unresponsive to auxins in terms of the percentage of cuttings rooted, but was the most responsive in terms of the numbers of roots per cutting. A greater percentage of cuttings from basal nodes were rooted than from apical nodes. Cuttings cut squarely at the base produced a radially-arranged root system, whereas an oblique cut resulted in a one-sided root system.Trimming the leaf area of cuttings to 10 cm² gave greater rooting percentages than trimming to 100 cm². In general, long cuttings (39 mm) rooted better than short cuttings (19 mm), however, there was an interaction between leaf area and cutting length, in which cuttings with short stems and large leaves had the lowest rooting percentage.     

Physiological studies for tropical tree improvement and conservation. Factors affecting root initiation in cuttings of Triplochiton scleroxylon K. Schum.

Applying auxins to freshly cut basal ends of leafy single-node cuttings of Triplochiton scleroxylon, an important timber tree of West Africa, considerably enhanced rooting percentages. The optimal concentrations in 10 μl MeOH droplets of a 50 : 50 mixture of α-naphthalene acetic acid (NAA) and indole-3-butyric acid (IBA) ranged from 8–40 μg according to clone. Larger amounts, which tended to increase numbers of roots per rooted cutting, inhibited root production in some clones. When applied singly, IBA was more effective than NAA in most clones.Leafless cuttings rarely rooted even when treated with auxins. Rooting occurred following the retention of 5 cm² of leaf lamina, and was maximal, as judged by rooting percentages, with 50 cm². The inability of leafless cuttings to root was associated with the rapid depletion of all carbohydrates in stem tissues, while those in unshaded leafy cuttings tended to increase.Percentages of cuttings rooting increased when temperatures of propagating-beds were raised above 20°C, and 28°C was optimal for most clones, especially if treated with auxins. Cutting survival declined above 28°C, although up to 38°C surviving cuttings rooted equally well.     

不同扦插方法对菊花生根的影响

全光喷雾条件下进行了不同基质、不同长度（下端节到剪口）、不同的剪口形状的菊花（Dendranthemamorifolium（Ramat）Tzvel.）扦插试验。结果表明,蛭石基质中菊花插穗的平均发根数极显著高于河沙和育苗土（P〈0.01）,河沙基质的插穗平均最长根长极显著高于育苗土（P〈0.01）,蛭石和育苗土的生根率极显著高于河沙（P〈0.01）。不同的长度（下端节到剪口）插穗的平均发根数、平均最长根长和生根率均无显著差异（P〉0.05）：平口与斜口之间的最长根长有显著性差异（P〈0.05）。插穗的根长和发根数存在着线性关系,其回归方程为y=5.516＋0.208x。     

Vegetative propagation of Inga feuillei from shoot cuttings and air layering

Cuttage and air layering were evaluated as means of vegetative propagation of the tropical woody tree, Inga feuillei. Effects of moisture management systems, leafiness, auxin application, and stem diameter on rooting of semihardwood cuttings were investigated. Cuttings were taken from 2-year-old seed-propagated, greenhouse-grown stock plants. Compound leaves were either reduced in area or removed entirely before auxin pretreatment with 0, 0.3, or 0.8% indolebutyric acid (IBA) followed by sticking under mist or in a polyethylene enclosure. Leafless cuttings did not root regardless of moisture management system or auxin pretreatment, whereas 55% rooting of leafy cuttings was observed. Leafy cuttings rooted significantly better under mist than in a polyethylene enclosure. Auxin treatment at the higher level increased rooting percentage approximately two fold for larger diameter cuttings (8.1 to 20 mm), but had no effect on the smaller cuttings (2 to 8 mm), and resulted in an approximately three fold increase in the number of roots/rooted cutting for both stem diameter classes. Auxin treatment did not affect rooting percentage of leafy softwood cuttings under fog, however it did increase the number of roots per rooted cutting. One hundred percent of air layered shoots rooted within 5 weeks with or without auxin pretreatment, and all rooted layers survived transplanting to soil. Possible implications of this research on agroforestry, selection, genetic improvement, and conservation are discussed.     

2个引进杨树无性系的硬枝扦插试验

以宁夏仁存渡护岸林场引进的截叶毛白杨、毛新×毛白73两个无性系的1年生硬枝为材料,以新疆杨为对照进行硬枝扦插试验,采用ABT-1号生根粉对插穗进行处理,比较其扦插生根情况。结果表明:2个无性系的杨树及新疆杨采用不同处理时,插穗生根情况不同;ABT-1生根粉处理的截叶毛白杨插穗在500 mg·L^-1浓度时愈伤组织形成率最大,达58.33%;毛新×毛白73枝条在600 mg·L^-1浓度时愈伤组织形成率最大,为41.67%。未用ABT-1生根粉处理的截叶毛白杨、毛新×毛白73和新疆杨的生根率高于处理过的。不同品种的杨树扦插生根率存在极显著差异,新疆杨生根率高达82.14%,高于截叶毛白杨与毛新×毛白73的,更适合进行扦插扩繁。     

竹柏扦插育苗技术研究

为给竹柏优良品系的扩繁提供技术支持,对不同措施处理下竹柏插穗的生根情况进行了试验。结果表明,不同季节扦插对竹柏插穗生根性状具有显著影响,春季是进行竹柏扦插的最佳季节,在春季进行扦插,竹柏的扦插生根率可达91.33%,平均生根条数为3.85条,平均最大根长为6.52cm;竹柏插穗选取的部位对竹柏生根性状有着极显著的影响,来自母树基部的插穗生根效果最好、中部次之,上部最差;不同留叶方式可极显著地影响竹柏扦插的生根率、生根数及最大根长,进行竹柏扦插,插穗应以保留2片全叶为最佳。     

杨树湘林新无性系不同部位育苗生长性状研究

新、老杨树无性系田间扦插育苗成活率,在湘林～90等5个新无性系与对照中汉-17杨之间有极显著差异,以中汉-17最低;5个杨树湘林新无性系间均无显著差异,可满足大田扦插育苗要求。成活率在苗干区分段问总体上随所取穗条部住的升高而有所下降;但第2、3、4区分段间无显著差异,表明杨树种苗上部的有芽茎干可以用作育苗种条。在夏季无抗旱措施情况下,年末保存率比春季成活率平均有所下降。大田育苗的保存率、成活率与水培时的皮层凸起呈正相关,反映先期根原基多、水培时易形成皮层凸起的无性系及区分段,可以期望有较高的育苗成活率和保存率。成活率、保存率与水培时的发根总长,苗高生长量与水培时的皮层凸起、不定根条数、总长间均没有相关性。试验显示,杨树新无性系扦插繁殖能力的鉴定,最重要、最可靠的程序是通过大田育苗的生产实践来检验。     

Structural root growth of young Veronese poplars on erodible slopes in the southern North Island,New Zealand

In New Zealand poplars are commonly planted on moist, unstable pastoral hill country to prevent or reduce soil erosion, thereby maintaining hillslope integrity and pasture production. Mechanical reinforcement by poplar root systems aids slope stabilisation. Root mass and distribution were determined for three Populus deltoides × nigra ‘Veronese’ trees aged 5, 7 and 9.5 year planted as 3 m poles at 8 m × 8 m spacing on a hillslope near Palmerston North in the southern North Island. Most of the structural roots (≥2 mm diameter) were distributed in the top 40 cm of soil. Vertical roots penetrated to about 1.0 m, being the depth of the soil above a fragipan. Total structural root dry masses (excluding root crown) were 0.57, 7.8 and 17.90 kg for the trees aged 5, 7 and 9.5 year, respectively. Total structural root length was 79.4 m for the 5 year tree and 663.5 m for the 9.5 year tree. Surrounding trees were estimated to increase root mass density to 3 times and root length density to 4–5 times the contribution of the single tree at 9.5 year. The study indicated that root development of wide-spaced poplar trees on hillslopes was minimal in the first 5 years but then increased rapidly. These results suggest that poplar trees established from poles may take at least 5 years to develop a structural root network that will effectively bind soil.     

母株年龄和插穗基部切削方式对日本落叶松生根的影响*

在无激素处理的条件下，１．５年生幼龄母株的插穗易于生根，平均生根率达９６．０％以上，且发根最大，偏根率低；４．５年生时，插穗生根率极显著低于１．５年生母株，而与８．５年生母株无显著差异；１２．５年生母株插穗生根率又极显著低于８．５年生母株。母株年龄与插穗生根率和偏根率分别呈显著的负相关（ｒ＝－０．９６５２）和极显著正相关（ｒ＝０．９９９３），但与生根量和平均最长根长度无显著相关。插穗基部切削方式不     

Influence of nitrogen,photoperiod, cutting type,and clone on root and shoot development of rooted stem cuttings of sweetgum

This study was designed to test the effects of nitrogen fertilization, photoperiod, cutting type, and clone on root and shoot development of stem cuttings of sweetgum (Liquidambar styraciflua). Differences in the growth of roots and shoots were observed as a result of weekly applications of varying levels of nitrogen (N) fertilization (0, 25, 50, 100, or 200 mg N/liter). As the concentration of N increased, new-shoot dry weight increased, but root dry weight decreased at rates greater than 50 mg N/liter. The percentage of rooted cuttings surviving also decreased as N concentrations increased past 50 mg N/liter. A night-interruption light treatment did not significantly affect survival percentages or the amount of root and shoot growth. Across all treatments, only 46% of all cuttings produced new-shoot growth within a 15-week period following rooting. Cutting type (terminal or sub-terminal) affected rooted cutting development. A higher percentage of terminal cuttings survived and were deemed plantable. In contrast, sub-terminal cuttings produced more shoot and root growth. Differences among clones were observed for all traits measured.Manipulating N fertilization, in conjunction with using clones that propagate well, has the potential of producing rooted cuttings of a size adequate for plantation establishment. However, higher percentages of cuttings that produce new shoot growth shortly after rooting must be achieved.     

The Effect of Gravity on Root Emergence from Cuttings of Some Tree Species

Poplar shoots trained horizontally and normally growing shootswere used to compare the effect of horizontal and vertical orientationin summer on the subsequent rooting of terminal cuttings; asignificantly greater number of preformed roots emerged fromcuttings of vertical shoots. This difference in rooting abilitymay be due to the lower concentration of indolyl-acetic acidin the upper than in the lower half of horizontal poplar stemsas shown by Leach and Wareing (1967). Decapitation of a seriesof these poplar cuttings (Populus ? robusta Schn.) showed thatwound-root production was influenced by the larger terminalbuds on vertical than on horizontal shoots. From a comparison of horizontal and vertical storage of applerootstock cuttings at 45 ?F in the autumn, 29 per cent moreof the horizontal cuttings than the vertical ones had a basalcallus in the following February. Of these cuttings which madesatisfactory shoot growth (over 5 cm) in the following summer,horizontal cuttings exceeded vertical ones by 80 per cent; aresult which was correlated with root production. In a second experiment with M II apple rootstocks in which cuttingswere both stored and grown at the same angle more roots occurredon cuttings placed horizontally rather than vertically, andthis orientation also induced the rootings of a greater proportionof leafy Worcester Pearmain apple cuttings.     

Improving regeneration of mahogany: techniques for vegetative propagation of four African mahogany species using leafy stem cuttings

Regeneration to ensure sustainable production and conservation of mahogany species globally is considered very important to foresters, investors in plantation, conservationists and timber industries worldwide. Natural regeneration of the mahoganies has been found to be far less than the rate of exploitation hence strong efforts are being made to develop other methods to regenerate mahogany seedlings to augment the low natural replacement and to ensure sustainability. This study was commissioned to investigate the effect of rooting media (river-sand, top soil and a mix of the two (50:50 v/v) on the rooting ability of four mahogany species (Khaya grandifoliola, K. ivorensis, Entandrophragma angolense and E. utile) using non-mist propagators. We investigated the effects of the source of stem cutting within a shoot (top, middle and basal position) on the rooting ability of stem cuttings from the four species in river-sand. Roots per cutting, longest root length and rooting percentage differed significantly among species in all three rooting media. Rooting ability was greatest in K. grandifoliola, which exhibited the highest average rooting percentage (73 %), longest average single root (9.9 mm) and the most roots per cutting (4.9). Rooting percentage was higher in the Khaya species than in the Entandrophragma species in all three rooting media. The mixed medium had the highest rooting percentage and the highest number of roots per rooted cutting in the two Khaya species, while the topsoil media had the best rooting percentage in the Entandrophragma species. Rooting of the two Khaya species can be maximized using a mixture of river-sand and topsoil. Cutting position within a shoot had significant impact on rooting in all four species with rooting percentage being best from middle positions in all four species. However, length of longest root and the number of roots per rooted cutting varied between the middle and basal portions. The study provides useful information for vegetative propagation of leafy stem cutting of the four African mahogany species, which could contribute to regeneration and conservation of these important timber species in the tropics.     

小叶芳樟扦插育苗技术及其不定根形成机理

采用石蜡切片法,对小叶芳樟(Cinnamomum camphora var.linaloolifera)插穗的生根特性及其解剖构造进行研究。结果表明,小叶芳樟根原始体属于诱导原始体,产生于木质部和韧皮部之间的维管形成层,其生根过程中未发现愈伤组织形成,属单一皮部生根型,不定根产生于插穗的下切口边缘向上至0.1~1 cm处。针对小叶芳樟扦插生根特性,优化外源激素浓度、留叶方式、插穗直径和扦插基质配方,筛选出最佳扦插组合为直径4 mm的半木质化插穗,保留2片完整叶子,经100 mg/L生长调节剂GGR6处理后,在混合基质(黄心土∶泥炭∶珍珠岩=3∶2∶1)中培育7~8周,扦插成活率达97.53%。