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.     

Effect of soil amendments and sawdust mulching on growth,yield and leaf nutrient content of highbush blueberry plants

The effects of soil amendments (elemental S, peat, crushed pine bark or crushed pine bark plus elemental S) mixed into the planting hole, with or without a sawdust mulch over the soil surface, on the early growth and yield of highbush blueberry bushes (Vaccinium corymbosum L., ‘Bluecrop’) grown in a mineral soil were investigated in a 3-year field study.Plant growth and yields were increased by additions of all amendments and generally followed the order: bark plus S > bark = peat = elemental S > control. The reasons for the positive growth responses probably differed among the treatments. In the control treatments, growth appeared to be limited by Mn and possibly Fe deficiency. For the S treatment, a decrease in the soil pH with a concomitant increase in levels of Mn and Fe probably stimulated the response. However, concentrations of both leaf Al and Mn were very high in the S treatment, and toxicities of these elements may have been limiting a further growth response. For the peat amendment, the growth response was probably related to both a decrease in soil pH and an improvement in soil physical conditions. For the bark amendment, the growth response is likely to have been pricipally related to improved physical conditions and also to the reasonably high Mn content of the bark itself. For the bark plus S treatment, the additional effect of reduced pH provided for an even greater response than that for bark alone. It was concluded that additions of organic matter and an acidifying agent to the planting hole can greatly increase early growth and yields of blueberries in mineral soil.     

不同无土基质对微型盆栽月季生长发育的影响

 研究了7 种无土复合基质对微型盆栽月季( Rosa hybrida‘Miniature Pink’) 生长与发育的影响,结果表明, 100%泥炭、70%泥炭+ 30%珍珠岩、70%珍珠岩+ 30%泥炭3 种基质比较理想, 对其生长及开花均表现为显著的促进作用; 微型盆栽月季无土基质的优化物理性状为: 容重0.12～0.19 g·cm^-3 , 比重1.6～1.9 g·cm^-3 , 含水量(风干基质) 6%～16% , 总孔隙度90 %～94 %。     

Nutrition of container-grown Callistemon citrinus and Hakea laurina

Callistemon citrinus and Hakea laurina were grown in peat/sand (PS) (1 ; 1, vv) container media using a central composite design in incomplete blocks to measure the response to N, P, K and lime, each at 5 levels. Both plants, although they are in the Myrtaceae and Proteaceae, respectively, showed similar nutritional responses. They reacted strongly to N, particularly in the absence of P. Hakea was more sensitive to P toxicity than Callistemon. The following nutrient levels are recommended in a medium with equal parts peat and sand: medium N (a total of 750 g m^?3 released over 8–9 months), low or zero P (50 g m^?3 or less), low K and low or zero lime giving a pH of approximately 4.5.     

The effect of Pinus radiata bark toxicity on the early growth of plants in containers

Fresh Pinus radiata bark will impair the growth of seedlings and struck cuttings of some species, e.g., Impatiens linearifolia, Coleus blumei cultivar ‘Golden Gem’, Engenia cyanocarpa, Hymenosporum flavum and Chrysanthemum morifolium ‘White Sands’; but not of Monstera pertusa, Camellia sasanqua ‘Lucinda’, Rhodondendron ‘Sir Robert Peel’ or Pilea cadierei. Partial elimination of the phytotoxicity was as effective as complete elimination in allowing normal growth of the plants.For sensitive species, the presence of the propagating mixture around the root systems at the time of planting helped to nullify the effects of the toxins. Bare-rooting the plants exposes them to a maximum set-back. The percentage of bark in a mixture also influenced the extent of the phytotoxicity.     

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.     

Analysis of adventitious root formation in isolated stem explants of Rhododendron

Factors affecting adventitious root formation were studied in isolated stem segments of three Rhododendron cultivars, ‘Catawbiense Album’, ‘Pink Pearl’ and ‘Van Weerden Poelman’, having different rooting ability. The experiments consisted of varying certain factors, while keeping the others constant.Root formation was always less in ‘Van Weerden Poelman’ than in the easy-to-root cultivars. Rooting usually occurred only in segments from young soft shoots. The length of the explants did not affect rhizogenesis. Removal of a strip of bark promoted adventitious root formation. Oxygen supply appeared to be essential since only inverted segments were capable of forming roots. Darkness was essential for rooting. The optimum temperature was 25°C. Root formation occurred only when a sugar was present in the medium. Rooting decreased with increasing osmotic pressure. Macroelements, boric acid and the pH of the medium did not play an essential role. Auxin was an absolute requirement for rooting, the kind and concentration depending on the cultivar used. Benzylamino purine at low concentrations increased root dry weight. GA₃ and abscisic acid decreased rooting.     

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.     

不同基质对越橘生长发育和叶片光合特性的影响

以二年生"都克"越橘苗木为试材,采用CIRS-2便携式光合仪测定光合指标与LA2400扫描仪扫描根系的方法,研究了不同栽培基质对越橘生长发育和光合作用的影响,以期筛选出越橘基质栽培中最佳配比。结果表明:在泥炭藓∶草炭∶珍珠岩=2∶1∶1、椰糠∶草炭∶珍珠岩=2∶1∶1、苔藓∶草炭∶珍珠岩=2∶1∶1这3种基质下植株生长发育较好,光合作用较强,其中泥炭藓∶草炭∶珍珠岩=2∶1∶1基质效果最好;秸秆∶草炭∶珍珠岩=2∶1∶1、松针∶草炭∶珍珠岩=2∶1∶1效果较差,植株生长发育不良。     

Determination of Salt Tolerance of ‘Camarosa’ and ‘Chandler’ Strawberries Grown in Perlite and Perlite

ABSTRACT

The effects of salt (NaCl) applications of various concentrations (0, 500, 1000 and 2000 mg/L) for 6 months on ‘Camarosa’ and ‘Chandler’ strawberry varieties grown in perlite and perlite:zeolite (1:1) media were investigated. In order to determine the salt resistance of varieties, the tolerance index (T.I.) and tolerance ratio (T.R.) were calculated on the basis of total chlorophyll content, and leaf and root dry weight. Also, the ability of keep in balance for potassium:sodium (K:Na) ratio in the aerial part and roots of plants were considered. It was determined that the highest T.I. and T.R. values calculated on the basis of leaf and root dry weight in cv. Camarosa in both media. Concerning the evaluations calculated on the basis of total chlorophyll, the results indicated that ‘Chandler’ is more resistant in perlite medium, ‘Camarosa’ is more resistant in perlite:zeolite (1:1) medium. K:Na ratio decreased with increasing salinity in both varieties. However, it was determined that K:Na ratio is higher in cv. Chandler, i.e., 0.83 than in cv. Camarosa (0.61). As a conclusion, it was determined that ‘Camarosa’ was more resistant to salt than ‘Chandler’. In addition, regarding the salt resistant performance of plants, perlite:zeolite (1:1) medium had more effective results than perlite.     

Micropropagation of gooseberry, Ribes grossularia

A method for rapid micropropagation of gooseberry (Ribes grossularia cultivar ‘Hinnonmäki Yellow’) was established. The optimum concentration for shoot production was obtained at 2.2 μM BAP and 0.05 μM IBA with MS nutrient medium. The Lepoivre salt medium with no hormones was used for elongation of shoot clusters, and in this medium about 50% of the shoots formed roots. For both rooted and unrooted shoots, 100% survival was obtained after transfer to soil. It was possible to store shoots in vitro for 130 days without any sub-culture and with 100% survival if the temperature was increased successively after cold storage.     

Transplanting Gladiolus plants propagated in vitro

In vitro propagated Gladiolus plantlets cultivar ‘Eurovision’, subcultured to a pretransplanting low-mineral and sucrose medium under high irradiance flux, developed functional roots, and after transfer to non-aseptic conditions, continued to grow without becoming dormant.Transplanted plantlets, after hardening, produced larger-size plants and cormlets (small corms) under non-aseptic conditions than formed in vitro, thus shortening the time for the propagation of large-size cormlets.     

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.     

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.     

Some effects of varied magnesium nutrition on the growth and composition of olive plants (cultivar ‘chondrolia chalkidikis’)

Olive plants (Olea europaea cultivar ‘Chondrolia Chalkidikis’) were grown in perlite: sand (1 : 1) cultures irrigated with nutrient solutions widely varying in magnesium (Mg) levels. When calcium (Ca) concentration in solution was 4 mM, maximum fresh weight (Fw) was produced with 0.4–2 mM Mg. Above 2 mM Mg in solution, fresh weight yield declined. The ratio of $\text{Ca}\text{Mg}$ in solution for optimum vegetative growth of olive trees was 2.Ca concentration of leaves and roots fell consistently with increasing Mg concentration in solution from 0.005 to 20 mM. When the concentration of Ca was 0.5 mM, an increase of Mg in solution from 3 to 20 mM did not further reduce Ca content of tissue. Mg concentration of leaves and roots increased, but not in proportion to the increase of Mg in the nutrient solution. An increase of Mg in solution from 2 to 10 mM was followed by a proportional increase of manganese (Mn) content of leaves. Above 10 mM Mg, a plateau in Mn concentration was reached.The zinc (Zn) content of leaves and roots was increased when Mg in solution increased up to 0.2 mM, then was reduced in the range 0.2–2 mM Mg and remained constant between 2 and 20 mM Mg. Other elements like copper (Cu) and iron (Fe) were not affected by increasing Mg concentration in solution.     

A greenhouse method for screening lettuce for resistance to Sclerotinia sclerotiorum

Agar blocks colonized by Sclerotinia sclerotiorum, causal agent of lettuce drop, were used as inoculum in screening for resistance to this pathogen in the greenhouse.Since the degree of resistance to the pathogen among cultivars varied with the time observed after inoculation, resistance was assessed by the number of days for 50% of the plants of each cultivar to die, as well as the number of plants that died. The cultivars ‘PI (Plant Introduction) 250427’, ‘Taiwan’, ‘PI 251790’, ‘PI 255568’, ‘MSU 73-44’ and ‘Bibb’ were found to have a higher level of resistance to S. sclerotiorum than the cultivar ‘Grand Rapids’ at 12 or 15 days following inoculation.     

东方百合品种‘西伯利亚’切花生产中替代泥炭的基质研究

以东方百合品种‘西伯利亚’（‘Siberia’）为试材,研究了在混配基质中用麦秆、玉米秆、椰糠、菇渣、豆荚等5种有机废弃物替代泥炭作为栽培基质的可行性。结果表明,5份泥炭︰2份珍珠岩︰1份蛭石︰2份麦秆、4份泥炭︰2份珍珠岩︰1份沙子︰3份玉米秆、2份珍珠岩︰2份蛭石︰3份椰糠︰3份沙子（均为体积比）等3种混配基质的各项理化指标均在无土栽培基质的理想范围内,用其栽培的百合,生长发育综合表现优于目前生产上常用的含70%泥炭的基质,其中又以4份泥炭︰2份珍珠岩︰1份沙子︰3份玉米秆的基质最优。     

Comparison of anti-oxidant activities and fruit quality attributes in four sweet bell pepper (Capsicum annuum L.) cultivars grown in two soilless media

This work was carried out to study the effects of two soilless media consisting of 80:20 [volume/volume (v/v)] mixtures of mosspeat and perlite, or cocopeat and perlite, on fruit quality and anti-oxidant activities in four cultivars of bell pepper (Capsicum annuum L.): ‘Traviata’ (green), ‘Inspratian’ (red), ‘Aracia’ (orange), and ‘Taranto’ (yellow). The results showed that the composition of the medium had a significant effect on the anti-oxidant composition and activities of the bell pepper fruit. Plants grown on 80:20 (v/v) mosspeat and perlite had significantly higher pericarp firmness, titratable acidity, total phenolic compound concentrations, 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability, and the hydroxy free-radical (?OH) scavenging ability. Fruit on plants grown on 80:20 (v/v) cocopeat and perlite had significantly higher vitamin C concentrations. Among the four cultivars tested, ‘Inspratian’ (red) was superior in more factors including pericarp thickness, dry matter content, titratable acidity, total soluble solids content, total phenolic concentration, DPPH scavenging ability, and vitamin C concentration. There was a significant interaction between cultivar and soilless medium composition, indicating that the response of bell pepper cultivars varied in the different media. The results of the present study highlight the importance of comparing soilless media in terms of their effect on fruit crop quality and anti-oxidant activity.     

Rapid propagation of Cucurbita pepo L. by culture of meristem tips

A tissue culture technique has been developed for the rapid multiplication of pumpkin (Cucurbita pepo L.) clones. Meristem-tips from seedlings of cultivar ‘Cinderella’ were grown initially on MS medium containing 2.56 mg l^?1 Kinetin and 8 mg l^?1 IAA, and then transferred to experimental media. Maximum shoot proliferation occurred on MS medium containing 1 mg l^?1 BA and no auxin. Cultures were rooted after 2–3 weeks on MS medium containing 8 mg l^?1 IAA and no cytokinin.