Effects of alternating light intensity on CO2 assimilation of Ficus elastica and Dieffenbachia Picta plants, grown for indoor landscaping.

Indoor landscaping increasingly uses plants on new hydroponic systems, including green walls, for greening private and public spaces, not always well or sufficiently lighted. Lamps are often essential to ensure a suitable light intensity for plant growth and for the production of a dense and brightly coloured canopy, even if many commonly used species originate in the lower layers of tropical ad subtropical forests and have a high ability to tolerate poor light levels. The photosynthetic response to light flecks is a well known characteristic of many plants native of the lower layers of forest and especially those living on the floor of dark and moist tropical forests. The effects on CO2 assimilation of a constant or alternating light intensity were tested in Dieffenbachia picta \u2018Camille\u2019 and Ficus elastic \u2018Decora\u2019 plants, grown under 8/16 hours of day/night in a phytotron. The compared intensities were 20, 40 or 80 \ub5mol m-2 s-1 for constant light and 20/40 or 40/80 \ub5mol m-2 s-1 for alternating light, at 8 minute intervals. The CO2 assimilation was measured throughout the 8 hours of lighting, by an infrared gas analyzer LI-6400XT, on completely expanded leaves. The light intensity regimes influenced the trend of CO2 assimilation curves and the total daily assimilated CO2 in both species. In Ficus the photosynthetic activity under constant 20 and 40 \ub5mol m-2 s-1 was very low (0.7-0.9 \ub5mol CO2 m-2 s-1 on average during the 8 hour light period) and increased to 1.4 \ub5mol CO2 m-2 s-1 under 80 \ub5mol m-2 s-1, with two well marked peaks after 0.5 and 5 hours from the start of lighting. The 40/80 alternated intensity resulted in a total daily assimilation of 54 mmol CO2 m-2, 33.2% higher than under 80 constant lighting. In Dieffenbachia the CO2 assimilation was around 0.2-0.6 \ub5mol CO2 m-2 s-1, averaged for the 3 constant intensities, whereas at 20/40 alternating lighting the rate increased to 1.2 \ub5mol CO2 m-2 s-1, equivalent to +67% on total daily assimilation

EVALUATION OF GROUNDCOVER ROSE CULTIVARS FOR LOW MAINTENANCE GARDENING AND LANDSCAPING.

The goal of the 3 year-research was to compare 59 cvs, launched by the most important European breeders, under a low maintenance regime, particularly without winter pruning, watering, fertilization and disease control all over the trial period. The experiments was carried out on a 1.300 sqm area included in ‘Raffaele Bazzocchi’s Rose Collection’ and placed in Po Valley, near Bologna (Italy). The place is typified by 780-1000 mm yearly rainfall and, over all, by dried and warm summer (e.g. maximum T. = 44°C in 2003). Floriferousness, flower characteristics, flowering length and flushes, hip development, bottom break production, canopy height and diameter, cover ground surface and disease sensibility were yearly tested. Moreover, two index were established to define the cultivar worth: Index of covering (C.I. to set out plant colour effect at flowering maximum) and Index of ornamental value (O.I. to quantify the plant ornamental value all over the period from May to September). At the end of the third year, ‘Deborah’, ‘Rustica 91’, ‘Crimson Cherry’, ‘Scarlet Meidiland’ and ‘Pink La Sevillana’ resulted the tallest cultivars and ‘Snow Storm’ the most vigorous (plant surface = 1.64 sqm); further ‘Altair’, ‘Bonica 92’, ‘Flaming Star’, ‘Pearl Mirato’ and ‘Pink La Sevillana’ plants proved to be too irregular and outspread under hip weight and to require pruning. All cultivars have continuous or recurrent flowering but spring peak is ever the most important (flower number/plant) and the most eye-catching thanks brighter colours and larger flower diameter. I.C. and I.O values ranged from about 0.2 to 2.0 and from 10 to 50 respectively. Data are discussed among cultivars with the same flower colour. Petal-fall bent and common disease susceptibility are reported for each cultivar

Effects of artificial light intensity and ambient CO2 level on photosynthesis of Araceae Species commonly used for interior landscaping.

The photosynthetic light-response curves of Aglaonema commutatum ‘Sylver Queen’, Anthurium andreanum ‘Dakota’, Dieffenbachia picta ‘Camilla’, Philodendron erubescens ‘Red Emerald’, Spathiphyllum wallisi ‘Mauna Loa’, and Syngonium podophyllum ‘Maya Red’ plants were analyzed after a 3-month acclimatization period in a phytotron under 380-400 ppm CO2 concentration, 26 ± 2°C temperature and 8/16 hours of light/night (20 µmol m-2 s-1 by neon lamps). CO2 assimilation of completely expanded leaves, grown during the acclimatization period, was measured by infrared gas analyzer, increasing photosynthetically active radiation (photosynthetic photon flux density; PPFD) from 0 to 200 μmol m-2s-1 photon flux (common indoor conditions) and with two CO2 levels (400-800 ppm). Light compensation point (Lc; μmol m-2s-1), apparent quantum efficiency (AQE; μmol CO2 × μmol PPFD-1), respiration (Rd; μmol CO2 m-2 s-1) and photosynthesis rate at maximum PPFD (A200; μmol CO2 m-2 s-1) are discussed and used to classify species and define the suitable intensity for artificial indoor lighting. After the acclimatization period, Lc was lower than 9 µmol m-2 s-1 PPFD for all species and both CO2 concentrations while Rd was contained between -1.2 and -0.1, with significantly higher values at 800 ppm CO2 only in Aglaonema, Dieffenbachia and Spathiphyllum. At PPFD of 200 μmol m-2s-1, CO2 enrichment increased assimilation from 34.7 (Ph. erubescens) to 93.1% (Syngonium), reaching 1.42 in Ph. erubescens and 6.26 umol CO2 × m-2 s-1 in Ph. pertusum. The high AQE values in Ph. pertusum, Ph. erubescens, Syngonium and Dieffenbachia demonstrate the relatively higher capacity of the four Araceas to promptly react to increased light and sun flecks, when grown under a low photon flux density

Compost-based growing media: influence on growth and nutrient use of bedding plants.

The agronomic performance and the mineral composition and trace element content in Begonia semperflorens \u201cBellavista F1\u201d, Mimulus \u201cMagic 7 hybridus\u201d, Salvia splendens \u201cmaestro\u201d, and Tagete patula 7 erecta \u201cZenith Lemon Yellow\u201d, were tested by growing the plants on substrates of white peat and 25\u201350\u201375\u2013100% green waste and sewage sludge (80% + 20% v/v) compost (CP). A commercial peat medium of black and white peat (2:1 v/v) was used as control. At flowering, the agronomic parameters were compared by ANOVA and plant nutritional status was compared by vector analysis. Substrate-species interactions (P < 0.001) were evident for all measured parameters. In the 25% CP medium all the species showed an increase or preservation of the studied agronomic parameters. Begonia grown in 25% CP, showed the highest dry weight (DW) and number of flowers. Other treatments were comparable to the control. Mimulus and Salvia showed the highest DW in the 25\u201350% CP. Mimulus, after a DW increase up to 50% CP, showed the steepest reduction as the CP increased further. Tagete showed no differences in DW up to 50% CP, or in flower number up to 25% CP, compared to the control. The additional increases of CP in the medium showed a DW decrease similar to that of Salvia. Vector analysis showed the use of compost mainly induced a decrease of P concentration in tissues, except for Begonia which remained unchanged. Plant tissues showed a general P reduction due to a dilution effect in the low compost mixtures (25\u201350%) and a deficiency in the higher CP mixtures. In contrast, an increase of Mg in the aboveground tissues of all species was detectable as compost usage increased, with the exception of Salvia which suffered a Mg deficiency. Vector analysis also highlighted a Ni and partial Fe deficiency in Tagete and Salvia

Device-supported spread of experimental results in a rose trial garden

The Rose Garden of the University of Bologna, where more than 1000 old and new rose species and cultivars are collected, includes an experimental field for the evaluation of landscape roses under low maintenance conditions, i.e., without irrigation, fertilization, phytosanitary treatments and pruning for the first 5 years after planting, and a mechanical pruning in the 6th year, just before dormancy breaking. Since 2002, about 160 new cultivars have been tested and characterized. Data concerning morpho-phenological parameters and disease incidence, the flower-cover index (FCI), the ornamental index (OI) and the graphs of flowering trend from April to October were elaborated each year and on average over the first five years after planting for every cultivar. The availability of these data could be very useful for The Rose Garden visitors, hobbyists, breeders, landscapers and nurserymen interested in a deeper information on the cultivars in field. The use of RFID techniques can be an easy means of spreading the experimental results and a way to broadcast changes in the garden, communicating up to date information in the same way as a public museum. The creation of datasheets started with the selection of the most suitable information for two types of users, professional and amateur. Data, recorded in a RFID microchip/cv can be viewed by visitors on personal mobile devices after downloading the app; amateurs have a direct and open access to information concerning commercial names, breeder, horticultural company, genealogy, curiosities and awards for each cultivar. Professionals can access the processed experimental data, too, by using a password sent after the online registration. The label with the cultivar name, used as microchip support, is practical and compatible with the distance for reading the microchip

In vitro shoot multiplication and rooting of wild Paeonia officinalis L., subsp. officinalis

Paeonia officinalis L., subsp. officinalis, is a herbaceous peony spontaneously growing on rocky slopes, up to 1,800 m of altitude, from Southern France to Albany, that includes Tuscan and Emilian Apennines. Its propagation occurs by rhizome or seeds under natural growing conditions; however, seeds need a couple of years to germinate. The aim of the present research was to set up a protocol for the in vitro propagation of this species, useful for its reintroduction in the natural environment, and suitable at nursery level. The combined effect of 6-benzyladenine (BA) and polyvinylpyrrolidone (PVP) was investigated on shoot multiplication of single shoots and small shoot clusters, in agarized culture media. A two-step rooting procedure was used, providing one-week culture of shoots in complete darkness on media enriched with indole-3-butyric acid (IBA) and their transfer to auxin-free media. Agarized media or perlite soaked in liquid media were used for both root induction and elongation phases.Complete culture survival was obtained with 1.0 g L-1 PVP and the use of small shoot clusters as explants. BA at 2.0 mg L-1 gave the maximum mean shoot multiplication (2.7) from a single shoot at the 3rd subculture; however, very short shoots were produced by shoot clusters after three further subcultures. BA at 1.0 gL(-1) allowed a constant multiplication (about 2:1) of well-elongated shoots regardless of the explant type. The multiplication rates reported here are quite low, but comparable to data available in the literature for in vitro grown shoots of wild herbaceous P lactiflora. The maximum rooting percentage (50%) was obtained in liquid media, for shoots from 1.0 mg BA treated with 2.5 mg L-1 IBA, although not different from other IBA treatments (1 and 5 mg L-1 ). The present results are promising with regard to the in vitro phases. However, they also suggest further research in improving rooting and achieving successful acclimatization of healthy plants. If this goal is reached, micropropagation might represent an alternative vegetative propagation method for the reintroduction in the natural environment of this species, and its release at nursery level as plant for gardens

STABILITY, NITROGEN MINERALIZATION CAPACITY AND AGRONOMIC VALUE OF COMPOST-BASED GROWING MEDIA FOR LETTUCE CULTIVATION

Seven composts were used as growing media for lettuce mixed with peat at 25 and 50% (v/v). On the unblended composts and the resulting 14 mixes were determined the main physical-chemical characteristics and the stability by means of a respirometric test in a liquid environment. The potential nitrogen (N)-mineralization capacity of the mixes was measured during the respirometric test solely by the ammonium (NH+ 4-N) determination. The lettuce pot-growing test was performed with and without fertilization; plant biomass and total Kjeldahl nitrogen (TKN) tissue content were measured after cultivation for two months. Compost origin, rate in substrates and fertilization affected plant growth and nitrogen uptake. Multiple regression analysis showed that the stability, proved to be a good predictor for plant growth inhibition. Moreover N-mineralization capacity showed a good fitting with plant uptake. The coupled stability and nitrogen mineralization test gives reliable information about the potential constraints in compost-based growing media

Vector analysis in the study of nutritional status of Philodendron cultivated in compost-based media.

Compost (CP) made from 70% ligno-cellulosic compounds and 30% sewage sludge was studied as a component of growing media in a 6-month Philodendron cultivation. CP's agronomic viability was evaluated via four plant-growth media containing 25\u201350\u201375\u2013100% CP and white sphagnum peat (WP) in comparison to a commercial substrate with white and black peat. Plant nutrition conditions were investigated by determining macro- (TKN, P, K, Ca, Mg and micronutrients (Mn, Fe, Cu, Zn, Na) and heavy metals (Ni, Cd, Cr, Pb) in roots and shoot tissues. Data were compared by vector analysis against control. Even if no leaf injuries were visible after 6-months\u2019 growth, a CP ratio of up to 50% caused growth depression of canopy tissues, as attested by the 37 and 36% reduction in total leaf dry weight and leaf area, respectively. Root growth decline was also notable at 25% CP, where 38% root dry weight reduction implied a significant increase (46%) in shoot\u2013root dry weight ratio. The investigation on nutrient tissue content showed high accumulation of Ni, Fe, Cr, Zn, Cd, Mn, Mg and P in roots; Mg appeared related to K deficiency. Above-ground nutritional status showed a severe lack of P, Mg and Mn. Vector analysis suggests the sewage sludge CP in Philodendron pot cultivation produces many such effects like direct toxic action and antagonistic action, resulting in a general nutrient imbalance in plants

Determinazione della stabilit\ue0, della mineralizzazione potenziale dell\u2019azoto e del valore agronomico di substrati a base di compost.

Seven composts were mixed with at 25 and 50% (v:v) of peat and used as growing media for lettuce production. The main physical-chemical characteristics and the stability of the unblended compost and the resulting 14 blend were determined by means of a respirometric test in a liquid environment. The potential N-mineralization capacity was measured during the respirometric test by the NH4+-N determination. The lettuce pot-growing test was performed with and without fertilization; plant biomass and TKN tissue content were measured after 2-month cultivation. Multiple regression analysis proved the respirometric index (defined by Oxygen Uptake Rate; OUR, mmol O2 kg-1 VS h-1) to be a good predictor for plant growth inhibition. Moreover, N-mineralization capacity showed good fitting with plant N-uptake and indicated limiting, suitable or potentially toxic conditions for plants. The coupled C and N-mineralization test gives reliable information about the potential constraints and chemical dressing requirement in compost-based growing media

Effetti di substrati a base di compost di diversa origine sulla coltivazione e lo stato nutrizionale di Poinsettia

Riassunto Sono state testate le prestazioni agronomiche e lo stato nutrizionale (N e P) di piante di poinsettia coltivate in vaso su otto compost, in miscela al 25% con torba bionda, con 2 livelli di fertilizzazione (F1/2 e F1). Nei compost puri il pH era superiore ad 8, la CE raggiungeva 1,57 7104mS cm-1. Il TKN era mediamente di 19 mg g-1 tranne che in due campioni (38 mg g-1). La miscelazione con torba ha avvicinato le caratteristiche dei mix a quelle richieste dalla coltivazione. F1 ha incrementato la crescita delle piante (peso secco + 76,7 % vs F1/2). L\u2019analisi vettoriale ha mostrato che l\u2019N \ue8 presente in quantit\ue0 tali da essere stoccato nella pianta e rappresenta un consumo di lusso, ad eccezione per il mix col compost verde. Al contrario il P \ue8 risultato limitante e il suo apporto, ha determinato una crescita delle piante proporzionale all\u2019incremento di N nei tessuti