Growth of Viburnum tinus in peat-based and peat-substitute growing media

To assess the growth of ornamental shrubs in peat alternative substrates, one ornamental species, Viburnum tinus L., was cultivated in a number of different substrates in two climates: a French oceanic (Oce) and a Spanish Mediterranean (Med). In Oce, three mixtures (1/1, v/v) of Finnish peat/yard compost, yard compost/raw coir and Finnish peat/raw coir were used while the expanded perlite/composted manure (1/1), forest compost/composted bark (1/1) and forest compost/cattle manure compost (2/3) were tested in Med. A mixture (1/1) of Finnish peat/pine bark compost was used in both climates as a control. Plants were cultivated at a density of six plants/m² in 4 l containers with drip irrigation. Plant height, dry mass, and leaf area were measured at intervals during cultivation. In Oce, substrates with yard compost or raw coir produced plants of similar size to those in the control substrate. In Med, forest compost/cattle manure compost mixture produced plants with the same height as those in the control mixture and the two other mixtures produced shorter plants. In both climates, substrates ranked the same whether height, dry mass or leaf area were considered. Using those parameters, significant effects of different substrates were revealed. Those effects are related to the substrate characteristics, mainly physical ones. As peat is used in a large range of situations, the experiment showed that substrate performance varies with its use, so alternative substrates can show better performance than those using peat.     

Effects of artificial amendments in potting media on Orthosiphon aristatus growth and development

Artificial polyacrylamide gel (PAG) and urea-formaldehyde resin foam (UFRF) amendments are used for putative enhancement of soil physical properties, including increasing their water holding capacity (WHC). Effects were investigated of these two amendments alone and combined on growth and development of Orthosiphon aristatus (Cats’ Whiskers) grown in either composted pine bark or washed river sand, including under transient water deficit stress. UFRF and PAG were incorporated into these potting media substrates at recommended rates of 30% (v/v) and 0.1% (w/w), respectively. UFRF incorporation reduced bulk density and increased air-filled porosity of composted pine bark from 0.24 g cm⁻³ and 43.3% to 0.18 g cm⁻³ and 50.2%, respectively. UFRF also reduced bulk density of sand from 1.43 g cm⁻³ to 1.17 g cm⁻³ and increased its air-filled porosity from 18.5% to 25.3%. PAG slightly decreased bulk density of composted pine bark to 0.23 g cm⁻³ and also reduced sand bulk density to 1.32 g cm⁻³. Water content of composted pine bark and sand was increased by PAG addition from 47.6% and 27.7% to 51.0% and 34.2%, respectively. However, UFRF and/or PAG did not increase plant available water (PAW) in either composted pine bark or sand. PAW was 23.8% and 14.4%, 23.6% and 15.8%, 22.8% and 14.8%, and 25.2% and 17.8% for composted pine bark and sand controls, these two substrates amended with UFRF, these substrates amended with PAG, and these substrates with UFRF plus PAG, respectively. Neither shoot length nor number was increased by adding UFRF and/or PAG. Similarly, neither shoot fresh nor dry weight was increased by UFRF and/or PAG amendments. UFRF and, moreso, UFRF plus PAG slightly delayed the onset of wilting by 4–15 h in water deficit stressed O. aristatus compared to control and PAG alone in composted pine bark (experiment 1), but PAG did not. However, in experiment 2, UFRF and/or PAG did not delay wilting in either composted pine bark or sand. Thus, when incorporated at suppliers recommended rates, neither UFRF nor PAG conferred appreciable benefits for O. aristatus plant growth in either composted pine bark or sand potting media.     

Distribution of Ilex and Juniperus roots in three container-media

Ilex crenata Thunb. cultivar ‘Green Luster’ and Juniperus horizontalis Moench. cultivar ‘Plumosa’ were grown in 3 container-media for 13 months. The container-media were dissected by 2 horizontal cuts to yield 3 depth zones, 3 equal concentric areas were outlined on the lower surface of each depth zone and root distribution determined. A greater number of Ilex roots were in the 2 inside concentric areas of the bottom two-thirds of the peat:perlite medium than in the same divisions of soil:peat:sand and pine bark:sand media. Juniperus roots were more evenly distributed through the depth zones of pine bark: sand than soil:peat:sand or peat:perlite media.     

不同基质对聊红槐扦插生根的影响

以细河沙、草炭、珍珠岩:草炭=1∶1为扦插基质,用400 mg/L的IBA和NAA处理聊红槐插穗,进行春季硬枝扦插,测定其生根指标,筛选出适合生根的扦插基质.结果表明:以河沙为基质,经过IBA处理过的插穗的生根率较NAA处理的好;以草炭为基质,经过NAA处理过的插穗较IBA处理的好;以珍珠岩:草炭=1∶1为基质,经过IBA处理过的插穗较NAA处理的好;同一激素处理的根系效果,浸泡时间3h的优于1h处理的.     

Effects of urea formaldehyde foam soil amendment on growth and response to transient water deficit stress of potted Flindersia schottiana saplings

Hydrocell™is a urea formaldehyde resin foam (UFRF) product used as a soil amendment. It is proposed to improve the physicochemical properties (viz. water relations and aeration) of the plant root zone. Flindersia schottiana is a tree species used in the ornamental horticulture industry. This study investigated the potential of Hydrocell™ [0–50% (v/v) incorporation rates] to promote growth of F. schottiana saplings during containerized nursery production in composted pine bark medium. The growth response of the potted saplings to transient water stress was also assessed. In addition, growth of F. schottiana saplings potted into three different soil types (sand, loam, clay) was assessed in the presence and absence of 30% (v/v) Hydrocell™. Under well-watered conditions in composted pine bark, Hydrocell™ treatments enhanced sapling leaflet numbers, with 30% (v/v) being the most beneficial treatment. However, no consistent significant differential effects of incorporation rate on either plant height or stem diameter were recorded. Extended time to wilting upon withholding irrigation was achieved, with the optimum Hydrocell™ rate being 10% (v/v). Among the three soil types compared, use of 30% (v/v) Hydrocell™ resulted in improved growth of potted F. schottiana saplings in the sand and loam soils, but not in the clay soil. These findings suggest that the UFRF, Hydrocell™, holds limited promise as a soil amendment for trees in the nursery phase. Optimum incorporation rates (v/v) would need to be determined for individual media types, specific irrigation regimes and individual taxa.     

Propagation of Wollemi pine from tip cuttings and lower segment cuttings does not require rooting hormones

Domestication of the recently discovered and highly endangered Wollemi pine has relied almost entirely upon serial propagation of cuttings from a very small conservation collection. This study assessed the requirement for applied auxin to induce rooting in tip cuttings and lower segment cuttings of Wollemi pine. Both types of cuttings proved easy-to-root, with mean rooting of 71% for tip cuttings and 82% for lower segments. Auxin application (at 1.5, 3.0 or 8.0 g indole-3-butyric acid/L) did not accelerate root protrusion from propagation tubes or affect final rooting percentages.     

野生毛葡萄扦插与嫁接试验

以难生根的野生毛葡萄插条为试材,研究基质配比、不同植物生长调节剂配比对其扦插生根率的影响。结果表明:经过吲哚丁酸(IBA)150mg/L处理后扦插在河沙:珍珠岩:泥炭体积比(1:1:1)的混合基质上,同时经过根部加温,插条缠膜,基质覆膜等综合技术措施,生根率可以达到67.5%;用50mg/L维生素C处理葡萄接穗后嫁接在野生毛葡萄砧木上,显著提高了嫁接成活率。     

Comparative effects of bark and peat based composts on the occurrence of vine weevil larvae and the growth of containerized polyanthus

A series of experiments was conducted to investigate the effect of inclusion of bark in potting composts on the numbers of vine weevil larvae on polyanthus plants. In 1989 more larvae were recovered from plants grown in peat compost than those grown in bark but these results were reversed when the study was repeated in 1990. Numbers of larvae also increased with higher ratios of bark:peat in composts but declined as the size fraction of bark used increased. The degree to which bark was composted did not appear to materially affect the numbers of vine weevil recovered. A strong, positive, relationship between larval numbers and foliage dry weight was found. Similarly, larval numbers were bigger with greater root development in bark composts. The results are discussed and it is suggested that the use of bark may promote more vigorous growth in polyanthus and thus enable plants to support more larvae.     

Evaluation and correction of nutrient availability to Gerbera jamesonii H. Bolus in various compost-based growing media

Nutrient deficiencies usually constrain the use of some composted materials as peat-substitute growing media even if some fertilizer is applied to the media. In this work, we assessed the suitability of various composted materials as such or mixed with peat for potted plant production, with special emphasis on their effects on nutrient availability to plants. Further, we examined the effect of vivianite [Fe₃(PO₄)₂·8H₂O] as a fertilizer and its mixture with humic substances (HS) on these growing media (particularly their effectiveness in preventing Fe deficiency chlorosis in alkaline substrates). A completely randomized experiment design was developed involving the growth of gerber (Gerbera jamesonii H. Bolus) and two factors, namely (i) the growing medium, specifically composted cork residue (C), compost obtained from a mixture of olive husk and cotton gin trash mixed with rice hulls and peat in a 1:1:1 volume proportion (OH), composted grape marc (GM), Sphagnum peat mixed with spent mushroom compost (M), coconut fibre (CF), and Sphagnum peat; and (ii) the Fe source (control without Fe, Fe-EDDHA, vivianite and vivianite + HS in a weight ratio of 10:1).     

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.     

不同基质和激素对地石榴扦插生根的影响

在塑料小拱棚下进行地石榴扦插繁殖试验，研究不同扦插基质和不同生长激素及浓度对地石榴扦插繁殖生根率的影响。试验结果表明：3种不同扦插基质中，1号基质（河沙：泥炭=2：1）的扦插生根率比2号基质（山地红壤：泥炭=2：1）高；5种生长激素中以浓度0．5g／kg的NAA处理效果最好，成活率达92％。扦插繁殖的最佳组合是采用半木质化枝条作插穗，经0．5g／kg浓度NAA处理，在河沙：泥炭=2：1混匀的混合土基质上扦插，应在实践中予以推广应用。     

基质配比对香石竹扦插成苗的影响

以香石竹品种‘云之蝶’(WR)和‘马斯特’(R3)为试材,采用随机区组设计,研究不同基质配比对香石竹2个品种扦插成苗的影响.结果表明:当基质配比为珍珠岩:草炭=5∶1时,2个品种的扦插生根率和成苗率均最高,且根系质量最好,不合格苗最少,是较好的基质选择.     

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.     

Importance of different components of green roof substrate on plant growth and physiological performance

Green roof substrate is arguably the most important element of a green roof, providing water, nutrients and physical support to plants. Despite this there has been a lack of research into the role that different substrate components have on green roof plant growth and physiological performance.To address this, we assessed the importance of three green roof substrate components (organic matter type, brick particle size and water absorbent additive) for plant growth and plant physiological performance. Lolium perenne (Ryegrass) was grown in eight substrates in a controlled greenhouse environment with a factorial design in composition of (i) small or large brick, (ii) conifer bark or green waste compost organic matter, and (iii) presence/absence of polyacrylamide water absorbent gel (‘SwellGel?’).We found that large brick substrates had a lower water holding capacity than small brick (?35%), which led to decreased shoot growth (?17%) and increased root:shoot ratio (+16%). Green waste compost increased shoot and root growth (+32% and +13%) shoot nitrogen concentration and chlorophyll content (20% and 57%), and decreased root:shoot ratio (?15%) compared to bark. The addition of swell gel increased substrate water holding capacity (+24%), which increased shoot growth (+8%). Total evapotranspiration (a proxy for potential cooling) was increased by greater shoot biomass and substrate water holding capacity. Overall, this study provides one of the first quantitative assessments of the relative importance of commonly used green roof substrate components. It is clear that substrate composition should be considered carefully when designing green roofs, and substrate composition can be tailored for green roof service provision.     

Mist propagation of peach and almond × peach hybrids

Several factors contributing to the successful rooting of stem cuttings of four peach clones and one almond × peach hybrid under intermittent mist were tested. With the almond × peach cross, leaf-bud cuttings were also tested.Severe cutting back of adult peach mother trees in winter favoured rooting of the cuttings, but less severe cutting back induced maximum roots per cutting.For short periods vermiculite was found to be a suitable medium. Sand alone or mixed with vermiculite or gravel gave poor results. Gravel alone or mixed with vermiculite was intermediate. For growing the rooted cuttings for a longer period, a mixture of perlite and peat was very suitable.A period of illumination of 3 h starting at midnight with incandescent light improved rooting of peach cuttings in August and October, but not in June.With cuttings obtained from old fruit-bearing peach trees highest rooting rates were obtained in July, but best root development occurred when rooting was carried out in October. In July rooting rate of basal cuttings was much higher than that of terminal ones. Success with leaf-bud cuttings (including a small branch piece) obtained from young mother trees of the almond × peach hybrid was only achieved at the end of May or in June.Dipping the base of peach cuttings in water before rooting was of advantage with one cultivar rooted in September, but of no advantage with another cultivar rooted in June.When the base of stem cuttings was dipped for a prolonged period in IBA solutions of various concentrations, highest rooting rates were obtained with 25–50 ppm IBA for peaches and with 200 ppm for the almond × peach hybrid. The addition of Phygon XL to this solution was of some advantage for peach cuttings. The concentration inducing maximum root development was higher than that required for maximum rooting and callusing. The optimal IBA concentration for rooting of almond × peach leaf-bud cuttings was 100 ppm.Penetration of the IBA into the leaf-bud cuttings reached a maximum 45 min a after floating them on a 100 ppm solution.Transplanting cuttings which had been rooted under mist was somewhat difficult; however, high rates of survival were obtained with cuttings planted in September which had developed a good root system.     

Effects of organic matter and controlled-release fertilizer on nutrient retention during intermittentmist propagation

Semi-hardwood cuttings of Ligustrum japonicum Thunb. and Juniperus conferta Parl. were propagated in sand or sand : peat (1 : 1 v/v) and top-dressed with osmocote controlled-release fertilizers at various rates. Soluble salts, NO^?₃, P and K leaching through media was greater in sand, especially with osmocote 14-14-14. Loss of P and K in both media was not as rapid as the loss of NO^?₃. The pH of leachate from sand : peat was significantly less than that from sand. The 18-6-12 osmocote provided steady nutrient release in both media.     

不同基质与植物生长调节剂对扶桑插条生根的影响

研究了珍珠岩、蛭石、河沙、菜园土、腐殖营养土等不同基质配比、不同生长素调节剂(IBA、IAA、NAA)及其浓度、生长调节剂与多效唑(PP333)混合使用对扶桑插条生根的影响。结果表明:河沙+腐殖营养土等体积混合的基质对生根的效果最好;IBA处理的生根效果较好,其中以IBA 150mg/L处理的生根率最高,为93.67%;IAA的处理中,以低浓度50mg/L的生根率最高,为90.67%;较高浓度NAA的处理平均生根数较多,但生根率较低。用含PP33320mg/L与IAA 50mg/L或与IBA 150mg/L的混合液处理均能提高扶桑插条的生根效果。     

红叶石楠夏季扦插育苗技术试验

试验于夏季进行红叶石楠不同基质、生根剂不同浓度和不同浸泡时间的扦插繁育技术研究,结果表明:红叶石楠选用混合基质(黄心土:粗河沙:草木灰=1:1:1),ABT1号生根粉0.02%浓度浸泡2h的平均生根率最高,达96.6%。该技术为红叶石楠种苗大规模扩繁提供科学依据。     

正交试验在含笑嫩枝扦插繁殖中的应用研究

利用正交试验方法,对含笑(Michelia figo)进行了嫩枝扦插繁殖试验.结果表明:以对最早生根天数影响最大的是生根剂处理时间,以处理2 h最早生根;对生根率影响最大的是生根剂类型,以根太阳处理生根率最高;对生根数目影响最大的是扦插基质,其中以沙作基质效果最好,生根剂浓度对生根数目也有显著影响,以200 mg/L浓度处理效果最好.综上所述:含笑嫩枝扦插的最佳组合是采用根太阳200 mg/L浸泡穗条基部2 h,使用沙作扦插基质.该组合扦插后100 d,生根率达到70%,生根数目平均达到4.12条.     

Effects of conifer wood biochar as a substrate component on ornamental performance,photosynthetic activity,and mineral composition of potted Rosa rugosa

A greenhouse experiment was conducted to assess the performance of biochar obtained from pyrolysis of conifer wood as a substrate component for growing potted Rosa rugosa plants. Rose plants were grown with different mixtures of sphagnum peat and biochar (100% peat, 75% peat–25% biochar, 50% peat–50% biochar, 25% peat–75% biochar; v:v). Increasing the biochar content from 25% to 75% increased the air content, bulk density, electrical conductivity, and K and Na concentration in the substrates. The addition of 25% biochar to the substrate showed promising potential for R. rugosa when compared with 100% peat given the similar growth performance, water-use efficiency, and ornamental quality (number of flowers and leaf colour). The Ca and Na concentrations in leaves and roots as well as the Mg content in roots increased as the biochar percentage in the substrate increased, whereas an opposite trend was observed for P and K concentrations. The best performance and ornamental quality of R. rugosa grown with 100% peat and 75% peat–25% biochar compared with 50 and 75% biochar treatments were attributed to a higher degree of photosynthesis, Soil Plant Analysis Development index, and pigment content. Overall, adding 25% of conifer wood biochar as a substrate component could be applied for economic purposes without detrimental effects on the yield and quality of potted roses.