Effect of handling and water stress on water status and rooting of loblolly pine stem cuttings

Two experiments were conducted to determine theeffect of handling, short-term storage, andinitial water stress on cutting water potential (_W) and rooting of loblolly pine(Pinus taeda L.) stem cuttings. First,stock plants and cuttings were measured for_W at predawn (04:00 a.m.) and earlymorning (09:00 a.m.). Cuttings were thensevered, wrapped in wet paper towels, andplaced in insulated containers for 2 or 7 h atapproximately 30 °C or for 21 h in coldstorage (4 °C). Water potentials ofcuttings were measured at the end of eachstorage period. Second, effects of initialwater stress on rooting performance of cuttingswere tested by withholding water from dormant(winter) and succulent (summer) cuttings forvarying periods of time. After each dryingtreatment, _W was measured on asample of cuttings and the remainder of thecuttings were transferred to a greenhouse withintermittent mist for 12 weeks.Storage of cuttings for long periods (7 to 21h) of time under low vapor pressure deficitconditions resulted in less negative waterpotentials of the cuttings. Dormant cuttingsrooted at higher percentages, even after beingexposed to lower values of _W Thelower values of _W in dormantcuttings could be attributed to higher ambientvapor pressure deficit during the drying phase. Results suggest that subjecting cuttings tomoderate water stress for a short period oftime does not adversely affect the rooting ofcuttings. Cutting water potentials below –1.7MPa appeared to reduce rooting of succulentcuttings and water potentials below –2.0 MPaaffected rooting in dormant cuttings.     

Genetic variation in rooting ability of loblolly pine cuttings: effects of auxin and family on rooting by hypocotyl cuttings

After about 20 days, hypocotyl cuttings from 20-day-old loblolly pine (Pinus taeda L.) seedlings rooted easily in the presence of the auxin indole-3-butyric acid (IBA), with roots forming directly from xylem parenchyma. In contrast, woody cuttings from 1-2-year-old hedged seedlings formed roots indirectly from callus tissue in 60-90 days, but IBA had little effect on rooting. Variation in rooting among hypocotyls from both half- and full-sib families was highly significant in response to IBA, and rooting did not occur within 20 days unless IBA was applied. Hypocotyls from poor rooting families tended to produce fewer roots per cutting than hypocotyls from good rooting families. Rooting by woody cuttings and hypocotyl cuttings from the same nine full-sib families was weakly correlated, raising the possibility that at least some common genetically controlled processes were affecting rooting by both types of cutting. The phytotropin N-1-naphthylphthalamic acid (NPA), supplied at 1 micro M with 10 micro M IBA, significantly inhibited rooting by hypocotyl cuttings from both good and poor rooting families, but there was no significant family x treatment interaction. Family variation in rooting ability may be a function of the frequency of occurrence of auxin-responsive cells in the hypocotyls.     

Fertilization,weed control,and pine litter influence loblolly pine stem productivity and root development

Following site preparation, three cultural treatments and three open-pollinated loblolly pine (Pinus taeda L.) families were studied on a gently sloping Beauregard silt loam in central Louisiana. The treatments were: (1) fertilization (either broadcast application of 177 kg N and 151 kg P/ha or none); (2) herbicide application (either broadcast application of herbicides during the first through third growing seasons, and felling of a few, scattered volunteer hardwood trees greater than 2.5 cm dbh during the third growing season or none); and (3) litter application (either broadcast application of 37 Mg/ha (oven-dried weight) of pine straw over the plots to form a 10 to 15 cm layer or none). The subplot treatment was planting stock, where in November 1988, 28-week-old container-grown loblolly pine seedlings from three open-pollinated families were randomly assigned to planting locations. Through five growing seasons, fertilization and weed control with herbicides resulted in the greatest loblolly pine productivity, but the use of herbicides severely reduced other vegetation. Applying litter, which was less effective than herbicides as a weed control treatment, increased the presence of blackberry (Rubus spp.) when herbicides were not applied. Applying litter resulted in a decrease and fertilization resulted in an increase in the number and length of live lateral roots. Soil temperature was reduced by litter application. Treatment responses were not influenced by loblolly pine family.     

扦插时期和基质种类对榛子嫩枝扦插生根的影响

试验以5 a树龄杂交榛(85-134)和欧榛(巴塞罗纳)当年生嫩枝为试材。结果表明:(1)杂交榛(85-134)和欧榛(巴塞罗纳)嫩枝扦插均可生根,以欧榛生根效果略好;(2)杂交榛(85-134)和欧榛(巴塞罗纳)枝条长生长动态呈"慢-快-慢"的"S"型曲线,在供试的三个时期中以枝条长生长速生期结束即7月初扦插效果最佳,两品种的生根率最高,分别达到71.1%和81.1%;(3)以珍珠岩和蛭石(体积比为2∶1)为扦插基质,其气、液、固三相比最理想,最有利于插穗生根。     

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.     

基质及插穗对北美红杉扦插生根的影响

北美红杉是重要的园林绿化和用材树种,种子繁殖发芽率低且采种困难,扦插繁殖成活率较高,林业生产上以扦插繁殖为主。通过不同种类采穗圃产生的穗条在不同的扦插基质中的扦插试验,研究不同穗条来源和不同扦插基质对北美红杉扦插生根率的影响,结果表明,珍珠岩、蛭石、河沙(1∶1∶1)生根率最高;第Ⅱ、Ⅲ、Ⅴ类插穗生根率最高,新梢抽生能力强,生长较快,无明显年龄效应和位置效应。     

The influence of stockplant environment on morphology,physiology and rooting of leafy stem cuttings of Albizia guachapele

Studies in controlled environmentconditions investigated the effects ofirradiance and nutrients (NPK) on morphologicaland physiological characteristics of Albizia guachapele stockplants, and rootingability of subsequently severed cuttings innon-mist propagators. The study assessed gasexchange and chlorophyll fluorescence ofstockplants before cutting severance and ofcuttings during the propagation period. Anegative interaction was found betweenincreasing irradiance(200–500 mol m^{minus 2} s^{minus 1}) andincreasing nutrient supply (0.25–1.25% NPK)on stockplant growth, and a similar effect wasfound in the subsequent rooting of cuttings.Rooting percentage decreased from 53.8% withlow irradiance/low nutrients to 11.2% withhigh irradiance/high nutrients. Single-node,leafy cuttings from high irradiance/highnutrient stockplants were much shorter thanthose from any other treatment, whichnegatively affected their rooting ability. Nodifferences were found among treatments inchlorophyll fluorescence ratios duringpropagation, suggesting that A.guachapele cuttings are dependant for rootingnot only on current photosynthesis, but also ontheir initial pre-severance reserves ofcarbohydrate. It was concluded that A.guachapele, which can be propagated with thenon-mist propagation system utilized in thisstudy, was markedly affected by pre-severancestockplant environment through its impact oncutting size and products of photosynthesis.Growing stockplants under low irradiance andlow nutrients resulted in longer cuttings withhigher rooting ability.     

The influence of nutrient and water availability on carbohydrate storage in loblolly pine

We quantified the effects of nutrient and water availability on monthly whole-tree carbohydrate budgets and determined allocation patterns of storage carbohydrates in loblolly pine (Pinus taeda) to test site resource impacts on internal carbon (C) storage. A factorial combination of two nutrient and two irrigation treatments were imposed on a 7-year-old loblolly pine stand in the Sandhills of North Carolina. Monthly collections of foliage, branch, stem, bark, and root tissues were made and total non-structural carbohydrate analyses were performed on samples collected in years 3 and 4 after treatment initiation. Seasonal fluxes of carbohydrates reflected the hypothesized use and storage patterns. Starch concentrations peaked in the spring in all tissues measured; however, minimum concentrations in aboveground tissue occurred in late winter while minimum concentrations in below ground tissue occurred in late fall. Increased nutrient availability generally decreased starch concentrations in current year tissue, while increasing starch in 1-year-old woody tissue. Irrigation treatments did not significantly impact carbohydrate flux. The greatest capacity for starch storage was in below ground tissue, accounting for as much as 400 kg C/ha per year, and more than 65% of the total stored starch C pool. The absolute amount of C stored as starch was significantly increased with increased nutrient availability, however, its relative contribution to the total annual C budget was not changed.     

Parameters affecting shoot production and rooting of cuttings from lodgepole pine hedges

By propagating lodgepole pine (Pinus contorta) cuttings in vivo, we obtained after 7 growing cycles (ca 3.5 years) in a greenhouse, sufficient number of cuttings from most families to establish clonal progeny tests. Twenty-one full-sib families with approximately 20 clones per family were studied for five years. Years when cuttings were set, families within latitude and clones within families differed significantly in rooting percentages, with the variance components 4.2%, 8.2% and 9.5%, respectively. One way to get a frequent and uniform rooting is to take cuttings from non-leading shoots since they have higher rooting percentage than leading shoots. Neither total length of the cuttings nor length of the primary needles were significantly correlated to rooting percentage. With appropriate management of the ortets and the cuttings during rooting, most clones could be included in a cutting propagation program.     

插穗及插壤对油橄榄扦插生根的影响

油橄榄（Olea europaea L）为本犀科木犀榄属（Olea）常绿乔木，原产于地中海沿岸地区，是世界著名木本食用油料兼果用树种。本文对插穗及插壤对油橄榄扦插效果的影响开展了相关试验研究，旨在为油橄榄产业的种苗生产提供一些思路与方法。     

沙棘不同节数插穗嫩枝扦插生根率比较

利用不同节数(芽数)嫩枝插穗进行扦插试验,结果表明不同节数嫩枝插穗扦插皆可生根,但生根率差异较大;1～2节(1～2芽)插穗生根率低,3节(3芽)以上生根率较高,生根率随节数(芽数)的增加而提高.     

Vegetative propagation of Dalbergia sissoo: effect of growth regulators, length, position of shoot and type of cuttings on rooting potential in stem cuttings

The effect of auxins (IAA or IBA at 100,200,500 mg L 1) on rooting and sprouting parameters differed significantly (p < 0.05).Rooting and sprouting percentages were higher in some treatments while other parameters were significantly higher in other treatments.The results of the present study revealed that rooting was significantly (p < 0.05) affected by the length of cuttings,as well as the position of shoots and type of cuttings.On average,86.0 per cent rooting was observed in the 30-cm long cuttings compared to the other two lengths of cuttings,i.e.,20 and 25 cm,irrespective of any auxin treatment.In a control set,without any auxin treatment,a maximum of 60.0% rooting was recorded in the 30-cm long cuttings and a minimum of 40.0% of the cuttings rooted in the 20-cm long cuttings.Similarly,cuttings collected from the lower and upper portions of shoots resulted in 72.5 and 52.5 per cent rooting respectively,irrespective of auxin treatments.Maximum rooting was observed in the lower portion (40.0%) of cutting compared to the upper portion (30.0%) in the control set without auxin treatment.Leafless branches produced maximum (72.0%) rooting compared to the leafy cuttings (35.0%),irrespective of the auxin treatment.The leafy cuttings produces a minimum of 15.0% sprouting and rooting in the control set.     

Phosphorus fertilizer,soils, and site preparation influence loblolly pine productivity

Growth and yield of 12-year-old loblolly pine (Pinus taeda L.) plantations were compared among five subsoil textures, seven site preparation methods, with and without phosphorus fertilizer. Phosphorus broadcast before planting increased the mean size of the loblolly pine trees. However, soil differences significantly influenced stand survival, and the method of site preparation significantly affected total stand yield. Therefore, the influence of phosphorus on total stand yield depended on soil type and site preparation method. The site preparation-fertilizer combinations yielding the most volume per soil type were: on the Lucy, Ruston, and Wagram soils, shear-windrow site preparation with phosphorus; on the Kirvin and Shubuta soils, chop-burn-harrow site preparation without phosphorus; on the Calloway and Henry soils, double chopping without phosphorus; on the Sawyer soil, chopburn-harrow site preparation with phosphorus; and on the Boswell, Cadeville, Gore, and Susquehanna soils, shear-windrow-harrow site preparation without phosphorus. Soil differences and phosphorus fertilization influenced the incidence of fusiform rust in 12-year-old stands of loblolly pine.     

马尾松插穗生根能力的家系变异与选择效应

用马尾松19个家系1年生苗及18个家系3年生苗为母株建立采穗圃,采集半木质化插条在人工气候室的条件下扦插试验,研究生根率、每穗生根数、最长根长、平均根长、当年插条苗高的家系间变异程度,生根性状间的表型相关,遗传力等。结果表明,各生根性状在家系间存在显著差异,且受较强的遗传控制。根系效果指数是评价马尾松插条生根能力的较理想综合指标,但从不同生根性状的相关性分析结果来看,用生根率性状更简便直观。在家系选择基础上建采穗圃,可明显提高马尾松扦插繁殖能力。从种子园优良家系中筛选出生根率高的优良家系建立采穗圃,是马尾松扦插繁殖应用的有效途径。     

Effects of IBA and NAA treatments on rooting Douglas-fir stem cuttings

The effectiveness of six IBA and fourNAA concentrations, four combinations of IBA and NAAconcentrations, and control were tested for theirability to enhance rooting frequency (%) ofDouglas-fir cuttings. Two IBA and one NAA treatmentswere also compared to the control for quality of rootsystem. Between 1984 and 1998, six independentstudies were conducted in mist or fog environmentswith the same 11 or 14 clones. Auxin concentrationstested ranged from 0 to 123 mM IBA and 0 to 10 mM NAA. Auxin, clone, and auxin by clone effects weresignificant in every study, although individual cloneanalyses showed only two clones to differsignificantly for auxin. All auxin treatments but the10 uM NAA treatment induced significantly greaterrooting percentage than the control, but no singleauxin, auxin concentration or combination of auxinswas clearly superior in every study. The 10 mM NAAconcentration was the only concentration tested thatreduced rooting percentage to less than the control. Both NAA and IBA appeared to have broad ranges ofroot-enhancing activity. However, within theeffective range of IBA evaluated, 24.6 mM produced thegreatest rooting percentage in four of five studiestesting IBA. NAA solutions with concentrationsbetween 2.5 and 7.4 mM NAA generally resulted insimilar rooting success. Rooting responses toincreased IBA and NAA were both nonlinear; rootingdecreased with both too little and too much auxin. Combinations of IBA and NAA in the same solution didnot increase rooting percentage above what wasachieved with one auxin. For root system quality,auxin treated cuttings in one study, had significantlybetter root systems than control, but there was nodifference in the other study in which root qualitywas estimated.     

Influence of irradiance on water relations and carbon flux during rooting of Shorea leprosula leafy stem cuttings

Single-node leafy stem cuttings of Shorea leprosula Miq. were subjected to a high, intermediate or low irradiance treatment for 16 weeks in an enclosed mist propagation system. Before rooting, maximum photosynthesis of the cuttings occurred at an irradiance of 400 micro mol m(-2) s(-1). Although none of the irradiance treatments affected the number of roots produced per cutting, the numbers of cuttings that formed roots were 50 and 30% in the high irradiance (diurnal range of 0-658 micro mol m(-2) s(-1)) and low irradiance (diurnal range of 0-98 micro mol m(-2) s(-1)) treatments, respectively, compared with 62% in the intermediate irradiance treatment (diurnal range of 0-360 micro mol m(-2) s(-1)). Low rooting frequency of cuttings in the high irradiance treatment was associated with water deficits (maximum leaf-to-air vapor pressure deficit (VPD) = 3.6 kPa), whereas cuttings in the low irradiance treatment had a low rooting frequency because they were below the light compensation point most of the time. In the intermediate irradiance treatment, cuttings withstood a daily maximum VPD of 1-2 kPa and recovered overnight from the previous day's deficit, as indicated by higher relative water content (RWC) and stomatal conductance (g(s)) in the morning than in the previous afternoon and evening. Higher RWC and g(s) of cuttings in all treatments on Days 14 and 21 compared with Day 8 probably indicated recovery from water deficit following severance and insertion of the cuttings in rooting medium. There were negative relationships between stem volume of cuttings and both number of cuttings that rooted and number of roots per cutting.     

Growth and water potential of j-rooted loblolly and eastern white pine seedlings over three growing seasons

The effects of j-rooting on water stress and growth of loblolly (Pious taeda L.) and eastern white pine (Pious strobus L.) were examined over three growing seasons in the field. Seedlings were planted in an area with severe herbaceous competition with either their roots planted straight or bent into a j shape. All seedlings were planted with their root collars placed at the soil surface. During the first year j-rooted seedlings consistently had lower water potentials but never statistically significant. Since both treatments were planted with the root collar at the soil surface, this trend was likely due to an initial shallower root system in j-rooted seedlings. In year three no differences in water potential were significant and no trends were evident. Growth did not differ significantly by treatment at any time but, by year three, j-rooted plants were consistently larger for both species.     

Loblolly pine cutting morphological traits: Effects on rooting and field performance

Shoot cuttings were harvested fromfour-year-old, loblolly pine hedges in March andSeptember of 1987, and placed into a series offactorial combinations of cutting length, diameterclass, and the presence/absence of a terminal bud toassess effects on rooting and field performance.Average rooting in the March trial was 50 percent andonly 20 percent for the September trial; however, thebest treatment in March yielded 100 percent rooting.Terminal bud status did not appear to influencepercent rooting. Shorter cuttings (5.1 or 7.6 cm)with an average diameter of 2 or 3 mm tended to rootbetter and develop more roots. Field performance ofthe rooted cuttings through age five suggests that theoriginal cutting does not require a terminal bud, butthe best set of morphological traits differ dependingon bud status. Considering both rooting ability andfield growth with an original tip bud present, thebest cutting dimensions were 5.1 or 7.6 cm long and 2or 3 mm in diameter. Without a tip bud present,cutting dimensions were restricted to 7.6 or 10.2 cmlong and 3 mm in diameter. Number of main roots wasa weak predictor of tree height or dbh at age five.     

外源激素对细柄阿丁枫嫩枝扦插生根的影响

以3年生细柄阿丁枫实生苗作试材,采用二阶非平衡巢式设计,研究外源激素种类及浓度对其扦插生根的影响,旨在为细柄阿丁枫无性繁殖提供指导.结果表明:外源激素种类及浓度对细柄阿丁枫嫩枝扦插生根均有极显著影响;扦插生根的最佳处理为300 mg/L NAA浸泡2h,各生根性状依次为生根率78.33％、根数23.73、根长4.26 cm,分别约为CK的3倍、6倍和4倍;就最佳处理而言,可将插穗生根过程分为3个阶段:0～20 d为愈伤组织产生期,≥20～30 d为不定根发生期,≥30～45 d为不定根大量形成期,各阶段均比CK提前15 d左右.