Nitrogen and calcium nutrition of Petunia × hybrida ‘Coral Sea’

The effects of N and Ca nutrition on plant growth and shoot elemental content of Petunia × hybrida Hort. Vilm. - Andr. ‘Coral Sea’ were evaluated. Nitrogen and Ca were applied separately or in combination in three experiments: (1) N at 0, 100, 200 or 400 mg l^?1; (2) Ca at 0, 75, 150 or 300 mg l^?1; (3) N at 0 or 100 mg l^?1 and Ca at 0 or 150 mg l^?1 combined factorially. Shoot and root dry weights, branch length and flower number were highest when plants received 100 mg l^?1 N. Plants treated with 150 mg l^?1 Ca had the highest shoot and root dry weights. Branch length was maximal at 300 mg l^?1 Ca.Nitrogen and Ca interacted to increase shoot dry weights, branch number and length, leaf area and flower number. Increasing N concentrations increased N and decreased P, Mn and Zn shoot contents. Calcium content of shoots increased while N, P and Mg decreased in response to increasing applications of Ca to petunia plants. Minimal N and Ca tissue concentrations for optimal P. × hybrida growth were 3.3 and 0.67%, respectively.     

Effect of vesicular—arbuscular mycorrhizae on growth of Chrysanthemum morifolium Ramat

Benefits of inoculation with the mycorrhizal fungus Glomus fasciculatus (Thaxter) Gerd. Trappe, on growth of Chrysanthemum morifolium ‘Circus’ were determined for varied conditions of N fertilization (375, 1500 or 3000 kg N/ha/year) and irradiance (6 or 800 μE m^?2s^?1) during lighting long-day treatments. High N fertilization combined with high level of irradiance produced the most mycorrhizal infection. Mycorrhizal infection generally increased C. morifolium height, especially with continuation of long-day lighting to 8 weeks. Mycorrhizae also improved flower, stem and root dry weight for most treatments, particularly the 1500 or 3000 kg N/ha/year fertilization rate and 4- or 8-week long-day light treatments. Although mycorrhizal inoculation increased C. morifolium growth most under extended long-day treatments, only the 2-week duration night lighting resulted in commercially acceptable plant size.     

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.     

In vitro somatic embryogenesis from Mangifera indica L. callus

The nucellus and globular adventitious proembryos were removed from 2-month-old fruits of mango (Mangifera indica L.) cultivars ‘Ono’ and ‘Chino’, and were cultured on sterile, solid Murashige and Skoog (MS) medium that had been modified as follows: half-strength major salts and chelated iron; 20% (v/v) coconut water (CW); 6% sucrose; 100 mg l^?1 ascorbic acid and 400 mg l^?1 glutamine. Embryogenic explants were sub-cultured after 4–6 weeks in liquid modified MS medium containing 2 mg l^?1 2,4-dichlorophenoxyacetic acid (2,4-D) instead of CW. Rapidly growing cultures were established and were sub-cultured monthly. Somatic embryogenesis was induced following sub-culture from MS medium with 2,4-D to MS without growth regulators and with or without activated charcoal (0.5%). Germination of somatic embryos appeared to be enhanced by 1 mg l^?1 benzyladenine (BA); however, most of the germinating embryos became embryogenic.     

Nitrogen fertilization under saline conditions in tomato and cucumber plants

Summary

Tomato (Lycopersicon esculentum, Mill.) and cucumber (Cucumis sativus, L.) seedlings were grown in a growth chamber in 4 litre containers filled with nutrient solutions. Four experiments were conducted with four NaCl levels factorially combined with four N levels. The concentrations of NaCl were 4, 25, 50, and 100 mmol l^?1 and 4, 16, 32, and 64 mmol l^?1 in the tomato and cucumber experiments respectively. The N levels in allexperiments were 2, 6, 10 and 15 mmol l^?1 added as NO₃^? or as NH₄⁺ + NO₃^? (2:1). Salinity had a statistically significant negative effect on all responses considered, although the effect was N source-dependent. Addition of N enhanced development of shoot and root dry weights of both species. The optimum N concentration in the nutrient solution varied between 6 and 10 mmol l^?1, although the most appropriate N fertilizer varied with species. Leaf Cl^? concentration decreased in both species when NO₃^? was used as the N source, whereas it increased in the comparative tissues of plants fed with NH₄⁺ + NO₃^?. The effect of treatments on the other nutrients show effects of excess of NaCl, as the form of N source interferes with the uptake of essential nutrients which may cause nutritional disorders.     

The effect of sucrose,silver thiosulphate and 8-hydroxyquinoline citrate on the quality of Lilium inflorescences cut at the bud stage and stored at low temperature

A continuous supply of sucrose together with 8-hydroxyquinoline citrate to cut Lilium Asiatic hybrid ‘Prima’ inflorescences resulted in buds opening satisfactorily and increased their longevity. The best results were obtained using 30 g l^?1 sucrose. Cut Lilium inflorescences could be stored at 1°C for 4 weeks without a great loss in potential vase-life and decorative value when the inflorescences were pre-treated with silver thiosulphate + 100 g l^?1 sucrose for 24 h before cold storage, kept in a cold room in a solution containing 50 mg l^?1 silver nitrate, and after cold storage kept in a solution containing 30 g l^?1 sucrose and 200 mg l^?1 8-hydroxyquinoline citrate. Such treatment greatly improved bud opening, increased the diameters of individual flowers and prolonged their life.     

The effect of nitrogen,volume of media,plant density and module shape on the growth of asparagus seedlings

There were three experiments in which the seedlings were raised in media contained in plastic cells. In Experiment 1, 150 or 200 mg l^?1 N were applied in factorial combination with cell volumes of 20, 32 or 50 cm³, There were 6 successional harvests. All cells were 7.5 cm deep and cylindrical in shape. Experiment 2 compared these 3 cell volumes at densities of 983, 1532 or 2440 plants per m². Cell diameters restricted the 50-cm³ cell to the 983, and the 32-cm³ cell to the 983 and 1532 plants per m² densities. 200 mg l^?1 N increased shoot growth, but not root growth. This increase in shoot growth was not considered advantageous. Seedling growth increased with increases in cell volume, but there were no responses to changes in plant density. Experiment 3 compared a cell having an inverted pyramid shape with a cylinder. The cylinder, despite holding 20% less media, produced the larger seedlings.     

Effects of nitrogen and phosphorus nutrition on the growth of asparagus seedlings

N was applied at 50, 100 or 150 mg l^?1 in factorial combination with P at 7.5, 15 or 22.5 mg l^?1 to asparagus seedlings. There were 6 successional harvests. N and P increased shoot dry weight by increasing mean dry weight and number of shoots. Increasing P had no effect on shoot growth at 50 mg l^?1 N. N increased root dry weight (crown and roots) by increasing root number, whereas P decreased root dry weight due to a decrease in mean root dry weight. N increased total plant dry weight, but P had no effect. N and P increased the partitioning of dry weight to the shoots, while partitioning to the roots increased with time. Plant analysis revealed that 2.6–2.7% N and 0.29–0.36% P, on a dry-weight basis, were present in the shoots at the later harvests with the higher concentrations of N and P. 100–150 mg 1^?1 N in combination with 15 mg l^?1 P produced a seedling suitable for transplanting into commercial fields at 6 weeks from emergence.     

Nitrogen-enriched ground kenaf (Hibiscus cannabinus L.) stem core as a component of soilless growth media

Summary

Four experiments showed that stem core (xylem of kenaf (Hibiscus cannabinus L.) in combination with sphagnum peat moss and fertilizer nutrients was a satisfactory growth medium for plants of ‘Toy Boy’ tomato (Lycopersicon esculentum Mill.). Greater shoot growth was achieved in media containing 20 to 35% kenaf by volume than 50%, and with fine kenaf (2–4 mm diameter) than coarser grades. In the absence of weekly solution fertilization, N-enrichment of the kenaf was necessary to support greater shoot growth than occurred in commercial growth media. Soaking the kenaf in solutions of increasing nitrogen (N) concentration (0 to 15,000 mg N l^?1) increased shoot growth, but urea ammonium nitrate (UAN, 30N–0P–OK) generally resulted in greater shoot growth than 20N–4.4P–16.6K at the same N concentration. The soaking time for kenaf in UAN was considerably less than in the complete fertilizer to produce similar shoot dry weights. Only a small portion of the kenaf in the growth media required pre-plant N enrichment provided the N concentration of the soak solution was increased in ‘ proportion to the volume reduction. Increasing the N concentration of weekly solution fertilization (20N–4.4P–16.6K) from 0 to 500 mg N l^?1 increased shoot growth irrespective of the N concentration of the kenaf soak solution. In media receiving 0 or 100 mg N l^?1 weekly solution fertilization, shoot growth increased with increasing N concentration of the kenaf soak solution.     

Callus and axillary-bud culture of Vitis vinifera ‘Sylvaner Riesling’

Healthy growth of serially subcultured callus of the grape Vitis vinifera cultivar ‘Sylvaner’ was obtained by incubation at 30° C in continuous light in a defined culture medium containing 2% w/v sucrose, 1.0 mg l^?1 1-naphthaleneacetic acid (NAA) and 0.2 mg l^?1 kinetin (K). Organogenesis was not induced in this callus by alteration in the absolute or relative levels of NAA and K.Continued shoot initiation was obtained by culture of axillary buds in a medium containing 10^?5 M Benzyladenine (BA). Plantlets could be generated from these shoot buds by transfer to media containing 10^?7 M BA or lacking a cytokinin.     

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.     

Agaricus macrosporus: An edible fungus with commercial potential

An investigation into the growth and nutrition of Agaricus macrosporus (Møll and Schäff) Pilát was performed to provide comparisons for studies with Agaricus bisporus (cultivated mushroom) and also as part of a programme to evaluate alternative Agaricus species for commercial use.A. macrosporus was grown on standard media; most rapid mycelial growth occurred at 24–27°C (maximum temperature for strong growth 30°C) on malt extract agar, although linear growth rates were lower than those of A. bisporus and A. bitorquis grown under similar conditions, and fruit-body primordia were rarely formed. Most rapid growth on agar occurred at pH 5–8, but little biomass was formed in shallow, pH-controlled liquid culture.A. macrosporus grew poorly on most individual carbon sources, with the exception of hexose monosaccharides. A. macrosporus grew well on complex nitrogen sources and amino acids, but ammonium nitrate was the only nitrate source to support any more than minimal growth. Rapid mycelial growth occurred in basal media containing 0.1–1 g l^?1 N (as arginine), corresponding to a C:N ratio in the media of between 5 and 35:1. A. macrosporus grew slowly, but fruited using the methods of commercial mushroom culture.     

Influence of medium-nitrogen level on growth periodicity of Ilex crenata Thunb. ‘Helleri’

Ilex crenata Thunb. ‘Helleri’ plants were grown in sand culture and supplied daily with nutrient solutions of 10, 40, 70 or 100 mg l^?1 nitrogen (N). Plant growth at all rates of N was characterized by an initial period of simultaneous shoot and root dry weight accumulation, followed by shoot elongation, root growth cessation, and major accumulations of N and dry weight. Plants grown at the greater N rates accumulated more N and exhibited a higher shoot-to-root ratio as a result of greater shoot than root growth. Plants grown at the higher N applications initiated extension growth before plants grown at lower N levels.     

The influence of naphthaleneacetic acid on the growth of in vitro cultivated seedlings of Bromeliaceae

The role of NAA during in vitro seed germination and subsequent growth was examined in three Bromeliaceae: Guzmania minor var. ‘Vella’ Mez, Guzmania lingulata var. ‘Splendens’ Mez and Vriesea splendens var. ‘Fire’ Lem. NAA incorporation in the medium resulted in a strong stimulation of root and shoot growth, with an optimum response at 0.5–0.8 mg l^?1. It is hypothesized that the usual slow growth of bromeliad seedlings in soil is primarily due to poor rooting, which is the result of auxin deficiency.     

Cercis siliquastrum L., Malus trilobata Schneid and Acer syriacum Boin and Gaill water use as affected by two fertilizer rates

There has been an increased demand for landscaping plants in Lebanon as a result of numerous reconstruction projects. Sustainable landscape regulations have created a need for regionally adapted taxa, especially those with low water requirements. Therefore, water use of container-grown plants and the impact of fertilization on water use were studied in the following native species: Cercis siliquastrum L. (six mother trees), Malus trilobata Schneid (two mother trees) and Acer syriacum Boin and Gaill (one tree). Two-year-old containerized seedlings were grown at The Ohio State University (Columbus, USA) under two fertilizer rates: 25 or 100 mg N L⁻¹ of 21 N–3.1 P–5.9 K water soluble fertilizer. Water use estimates were made by saturating the containers early in the morning, allowing them to drain for 1 h, weighing them and re-weighing approximately 5 h later. Although there were differences in seedling heights, those grown at 25 mg N L⁻¹ were taller than those at 100, there were few differences in water use per seedling. In August, Cercis seedlings grown under 100 mg N L⁻¹ had higher height adjusted water use (g water cm⁻¹ height h⁻¹, a method for standardizing water use among different sized plants) than those grown under 25 mg L⁻¹. However, there were no differences in height adjusted water use in September attributed to fertilizer rates. In September, Acer seedlings had higher water use cm⁻² leaf surface area under 25 than 100 mg N L⁻¹. There were no differences in water use among the progeny from the six Cercis mother trees. However, the seedlings from one Malus tree had higher water use cm⁻² leaf surface area than those from the other tree, even though the extant trees were separated by less than 20 m.     

Production of inter-section hybrids between Primula filchnerae and P. sinensis through ovule culture

Inter-section hybrids were obtained in the reciprocal crosses between Primula filchnerae (2n = 2x = 24) of Sect. Pinnatae and P. sinensis ‘Fanfare’ (2n = 2x = 24) of Sect. Auganthus by rescuing ovules on half-strength (1/2) Murashige and Skoog's (MS) medium supplemented with 50 g l⁻¹ sucrose, 2.5 g l⁻¹ gellan gum, 0.1 mg l⁻¹ α-naphthaleneacetic acid (NAA), 0.1 mg l⁻¹ 6-benzyladenine (BA) and 50 mg l⁻¹ gibberellic acid (GA₃). In ovule culture, germination occurred with radicle elongation but no plumule was observed. The radicle kept on the initial medium showed root proliferation with callus formation. When the calluses were transferred to (1/2)MS media containing 30 g l⁻¹ sucrose and 3 g l⁻¹ gellan gum, without plant growth regulators (PGRs) or with 1 mg l⁻¹ zeatin and 0.1 mg l⁻¹ NAA, plantlets were regenerated. The plants thus obtained were confirmed to be hybrids through flow cytometry (FCM) and random amplified polymorphic DNA (RAPD) analyses. The hybrid obtained when P. filchnerae was used as the maternal parent was diploid, whereas hexaploid hybrid was obtained when using P. sinensis as the maternal parent. The hexaploid hybrid might be produced through chromosome doubling of a triploid originated from the fertilization of P. sinensis with unreduced pollen of P. filchnerae.     

Effects of growth regulators on growth and flowering in Hippeastrum hybridum hort

Soaking of bulbs in 3 concentrations of indoleacetic acid (IAA), gibberellic acid (GA₃), 2-chloroethyltrimethyl ammonium chloride (cycocel) or 2-chloroethylphosphonic acid (ethrel) showed various responses on growth and flowering. IAA increased the weight and number of bulblets, GA₃ increased bulb weight. Cycocel (1000 mg l^?1) increased the number of flowers, while GA₃ increased the diameter of the flowers.Application of IAA at 100 mg l^?1 and GA₃ at 10, 100 or 1000 mg l^?1 twice as foliar spray at an interval of 30 days promoted the number of bulblets on the treated plants, while high concentrations of cycocel and ethrel (1000 mg l^?1) increased the weight of bulblets. All concentrations of IAA, GA₃ and 1000 mg l^?1 cycocel increased the number and size of the flowers.     

Effects of controlled-release fertilizer on root and shoot growth of Cotoneaster divaricata Rehd. & Wils.

Semi-hardwood cuttings of Cotoneaster divaricata grown in 926 cm³-containers were top-dressed with controlled-release Osmocote (18.0 N-2.6 P-10.0 K) at levels of 0, 2, 3 or 6 g/l of container. Optimum shoot and root growth was obtained at 2 g/l. Applications of controlled-release fertilizer significantly increased foliar N and P concentration, but not foliar K. The most desirable shoot-to-root ratio occurred at 2 g/l.     

Regulation of postharvest flower senescence in Zinnia elegans Jacq.

Postharvest decorative life of Zinnia elegans flowers was prolonged by holding-solutions containing 8-hydroxyquinoline citrate (8-HQC) and sucrose. Flowers lasted longest in a solution of 200 mg l^?1 8-HQC and 1% sucrose. Flowers held in 2 or 3% sucrose and 200 mg l^?1 8-HQC developed necrotic lesions on ray florets and foliage. The decorative life of flowers held in 0.25 or 0.5% sucrose and 200 mg l^?1 8-HQC was extended beyond those in de-ionized water, but this extension was less than, or equal to, the postharvest life of those in 1% sucrose and 8-HQC (200 mg l^?1), depending on the cultivar. Postharvest life of flowers produced in May — June under natural photoperiod was significantly longer than that of flowers produced during February to April under a 14-h day provided by incandescent light.     

Conservation of Vanilla species, in vitro

Vanilla (Vanilla planifolia) is a crop of great commercial importance as the source of natural vanillin, a major component of flavor industry. The primary gene pool of V. planifolia is narrow and is evidently threatened due to destruction of its natural habitats making the secondary gene pool important as a source of desirable traits especially for resistance to diseases. Many species of vanilla are considered rare and endangered hence an urgent need to conserve them, arises. Effective procedures for micropropagation and in vitro conservation by slow growth in selected species of vanilla, are described. Synthetic seed technology was standardized by encapsulating 3–5 mm in vitro regenerated shoot buds and protocorms in 4% sodium alginate, which could be stored up to 10 months with 80% germination in sterile water at 22 ± 2 °C. In vitro conservation technology of Vanilla was standardized and shoot cultures could be maintained for more than 1 year without subculture, on slow growth medium, i.e. Murashige and Skoog medium supplemented with 15 g l⁻¹ each of sucrose and mannitol in sealed culture vessels at 22 ± 2 °C. These cultures were maintained in vitro for more than 7 years with yearly subculture. The conserved material could be retrieved and multiplied normally in MS medium with 1.0 mg l⁻¹ BA and 0.5 mgl ⁻¹ IBA. The in vitro conserved plants showed good growth and developed into normal plants. This synseed and in vitro conservation system can be utilized for conservation and exchange of vanilla genetic resources.