1,720,989 research outputs found
Propagation of Artemisia arborescens L. by stem-cutting: adventitious root formation under different conditions
Full text linkArtemisia arborescens L. has gained a strong importance worldwide due to its many industrial uses and it has been recently considered as ornamental plant. A major constraint to its widespread cultivation is represented, by far, by the scarce availability of high-quality plant material for field establishment; hence, development of a fast and effective methods for its vegetative propagation is needed. An experiment was conducted to assess the effects of different harvest periods, NAA, and rooting substrates on rooting of stem cuttings of A. arborescens.
Semi hardwood cuttings were collected from wild plants in February, April, and November. Half of the material was treated with 0.4% NAA and placed on different mixtures of sphagnum peat and perlite (2 : 1, 1 : 1, and 1 : 2 v/v) under mist. After 40 days the percentage of rooted cuttings was significantly influenced by the harvest period as cuttings collected in February showed the highest rooting rate, and numerous alive but not rooted cuttings evidenced callus formation. In contrast, the use of different rooting substrates as well as NAA addition did not show any significant effect on rooting capacity. The best results, in terms of root number (4.2) and root length (8.8 cm), were achieved on cuttings grown in a 1 : 1 v/v sphagnum peat : perlite mixture, without NAA application
Biowaste-derived humic-like substances improve growth and quality of orange jasmine (Murraya paniculata l. jacq.) plants in soilless potted culture
No full textHumic-like substances (HLS) are among the most used biostimulants in agriculture as a means for improving plant growth, nutrient uptake, crop yield, and stress tolerance. HLS derived from municipal biowastes were applied as a substrate drench in order to evaluate their biostimulatory effect on the growth and ornamental quality of Orange Jasmine (Murraya paniculata [L.] Jacq.) potted plants. Two HLS, derived from the digestion of the organic humic fraction and from composting of a mix of sewage sludge digestate and gardening residues, were compared with a commercial leonardite-based product in the framework of a greenhouse experiment in soilless culture. The application of the two biowaste-derived HLS resulted in plants showing a 39.9%, 87.0%, 111.6%, 35.4%, 37.9%, 35.3%, and 81.3% increase in plant height, number of flowers and fruits, leaf production, total dry biomass, root length, and water use efficiency, respectively, compared to those treated with the commercial product and the untreated (control) plants. The enhanced growth performance of HLS-treated plants was due to the higher chlorophyll relative content (+24.2% on average) and net photosynthesis (+114.7% on average) of their leaves. The positive results obtained from the application of non-commercial HLS suggest that biowaste recycling is a sustainable and environment-friendly source of biostimulants, as an alternative to agrochemicals and existing leonardite-based plant biostimulants
Biowaste versus fossil sourced auxiliaries for plant cultivation: The Lantana case study
No full textSoluble bio-based substances (SBS) were isolated from the anaerobic digestate of the organic humid fraction of urban waste and from the compost obtained from a mix of digestate, gardening residues and sewage sludge. These were compared with a commercial Leonardite-based product for their effects on the growth and productivity of two Lantana species. The SBS were found more powerful than the Leonardite-based product in enhancing plant photosynthesis, growth and aesthetic effect, improving flower quality, and optimizing water use efficiency. Enhancement factors of plant performance indicators by SBS ranged from 1.2 to 3.3 relatively to the control plants, and from 1.3 to 2.4 relatively to plants treated with the commercial Leonardite product at equal applied dose. The results are in line with findings published for other case studies performed with horticultural and ornamental plants. They confirm that municipal biowaste is a viable feedstock to obtain specialty chemicals that can efficiently replace fossil sourced products in agriculture. Options for further development work are discussed
The effect of saline water on Phillyrea angustifolia L. seedlings
No full textWater limitations in the Mediterranean areas are very common and the use of saline water for plant irrigation is becoming a necessity. Salinity generally affects plant growth and physiological processes, and can eventually lead to leaf injuries and plant death. For these reasons, the selection of salt tolerant species is a priority for landscaping purposes in the Mediterranean areas. The objective of this study was to evaluate the effect of saline water on Phillyrea angustifolia plant performance. Seventy-five rooted cuttings were grown in the greenhouse in 4-liter pots and irrigated for 5 months with saline water at different NaCl concentrations for two consecutive years. In 2010, 45 plants were irrigated with 0, 40 and 80 mM NaCl water; in 2011, 30 plants were irrigated with 0, 100 and 120 mM NaCl water. No signs of leaf injury were observed in any of the two years or at any NaCl concentration. On the other hand, photosynthetic rates and stomatal conductances were reduced at all NaCl concentra¬tions. Reductions in shoot elongation were significant in both years, while shoot diameter growth and dry weights were affected only by high NaCl concentrations in the second year. In 2011, plant dry weight was reduced by 52% at 100 mM NaCl and 55% at 120 mM NaCl. Roots were highly susceptible to NaCl with a biomass reduc¬tion of 64 and 66% at 100 and 120 mM NaCl, respectively. Both leaf area and dry weight were influenced by NaCl with a reduction of over 50% at 120 mM NaCl. No significant effect was observed in biomass partitioning with the exception of a decrease of partitioning to roots at the highest salt concentrations. Phillyrea angustifolia plants were able to survive to all ranges of NaCl tested but CO2 fixation and shoot elongation rates were already reduced by moderate salt concentrations
Studi preliminari sulla propagazione gamica e vegetativa di Hypericum perforatum in ambiente mediterraneo
No full textLa conoscenza dei fattori che influenzano la propagazione di una specie rappresenta un passo cruciale nella messa a punto di strategie per la sua moltiplicazione di massa e introduzione in coltura, sia in campo che in ambiente controllato. Sono stati approfonditi alcuni aspetti della propagazione gamica di Hypericum perforatum (di cui è nota la bassa germinabilità del seme), verificando in particolare gli effetti di variabili diverse (soddisfacimento delle esigenze in freddo, temperatura, substrato, presenza di PGPR, batteri promotori della crescita). Sono stati inoltre approfonditi gli studi sulle potenzialità di moltiplicazione vegetativa della specie, da proporre come possibile alternativa all’impiego del seme. Sono state pertanto prelevate talee semilegnose da piante di H. perforatum al secondo anno di vita, successivamente poste a radicare su tre diversi substrati, con e senza l’impiego di un ormone radicante (NAA). Al termine della prova sono stati rilevati percentuale di radicazione, lunghezza e peso (fresco e secco) delle radichette. I risultati ottenuti hanno mostrato il positivo effetto della vernalizzazione sulla germinazione in tutte le condizioni sperimentali, mentre la prova di moltiplicazione agamica ha evidenziato un diverso comportamento rizogeno in funzione del substrato impiegato.The knowledge of the factors that can influence the propagation of a plant species is a key factor in the pointing out of strategies for its mass multiplication and cropping, both in open field and in controlled conditions. Some aspects of sexual multiplication of Hypericum perforatum (dealing with a generally low seed germinability) have been studied, firstly verifying the best seed germination conditions, in relation to temperature, growth substrate, pre-chilling and presence/absence of PGPR (Plant Growth Promoting Rhizobacteria). Furthermore, the potentialities of vegetative multiplication for the species were studied, with the aim to suggest this technique alternatively to the use of seeds. The trial about vegetative multiplication was performed picking up semi-woody cuttings from 2-years-old H. perforatum individuals. The cuttings were put for rooting into three different substrates, with and without the use of a rooting hormone (NAA – Naphtalenacetic acid). The rooting rate of cuttings was evaluated, and the produced roots were counted and measured as for length and fresh and dry weight. The results obtained have shown the positive effect of pre-chilling on the germination percent in all experimental conditions, whereas the trial about vegetative propagation has shown a different roots emission rate with varying the used substrate
Control of powdery mildew in cut roses using natural products in the greenhouse.
No full textRoses grown under greenhouse cultivation are commonly affected by diseases and regular fungicide applications are commonly used. The aim of this research was to identify natural products that can substitute and reduce the health and environmental impacts of typical chemical treatments in the control of powdery mildew [(Podosphaera pannosa (Wallr. Fr.) de Bary] and grey mould (Botrytis cinerea Pers.). Treatments were applied in the greenhouse on the cut rose cultivars Sunluck (Gold Strike®) and Nirpbredy (New Fashion®) growing in a soilless system. Oregano and clove essential oil at 0.5 ml/l (an emulsifier was added) and sodium bicarbonate (NaHCO3) at 4
g/l were sprayed on rose plants to runoff. The controls were untreated roses and a standard chemical control (the fungicides Dinocap, Triadimenol, Dimethomorph+Sulphur, Bupirimate, Dithianon, Iprodione and Thiram) was applied in rotation. Sprays were applied every 7-10 days after the first symptoms of disease appeared. Disease incidence was checked on 100 leaflets and symptoms were evaluated using a scale from 0 (no disease) to 7 (76-100% infection). At three different times (June and November 2005 and January 2006) biometric data (stem height, stem diameter, stem flexibility, flower diameter, number of petals/flower and thorniness) and colorimetric analysis of the leaves were evaluated in order to determine the effect of treatments on cut rose quality. Treatment with essential oils and NaHCO3 was able to control the incidence and the severity of powdery mildew on roses. Ambient infection of grey mould was low and
comparisons between treatments were not possible. Significant differences among the chemical and natural product treatments were found for all traits examined. Although NaHCO3 treatment controlled powdery mildew to a greater extent than essential oils, it resulted in slight phytotoxicity. These results indicate the potential use of natural products to control powdery mildew of roses and could be a good alternative to chemical fungicides. However, differences in response to powdery mildew depend on the cultivar susceptibility, period of treatments and level of control needed
A simple and accurate model for the non-destructive estimation of leaf areas in genotypes of Plumeria rubra L
No full textLeaf area (LA) is an important parameter in many plant modelling studies. There is a need for a simple, accurate and
non-destructive model to predict LA in physiological experiments in which destructive LA sampling is not allowed
(e.g., rare plants or genetically segregating populations). In this study, a model for LA estimation was developed for
Plumeria rubraL. using simple linear measurements of leaf length (L) and maximum width (W). Two experiments
were carried out, one in 2012 (on seven commercial genotypes: 'California Sunset', 'Christina', 'Elsie', 'Gina', 'J.J. Mini
White', 'Panittas Red', and 'Pixie Dust') and one in 2013 (on one genotype 'Divine') under greenhouse conditions, to
test whether a model could be developed to estimate LAs of P. rubraacross genotypes. Regression analysis of LA vs.
L and/or W revealed several models that could be used to estimate the area of individual Plumerialeaves. To develop
a model to estimate individual LA values accurately for all genotypes of P. rubra, measurements of both L and W
should be included. The proposed linear model [LA = 4.15 0.66 (L W)] was adopted for its accuracy, highest R
2
value (> 0.96), smallest mean square error (MSE), and smallest predicted residual error in the sum of squares
(PRESS), and whose PRESS value was close to the sum of squares for error (SSE). Validation of the model using L
W measurements of leaves was carried out on an independent dataset derived from another genotype (‘Divine’) in
2013. Correlation coefficients showed that there were strong relationships between predicted LAs and observed LAs,
with an over-estimation of 4.0% in the prediction. This model can therefore be adopted reliably to estimate LAs in
P. rubra, non-destructively
Dual Role of Copper in the Micropropagation of Olive: Morphological, Physiological, and Biochemical Responses from Beneficial Growth to Lethal Stress
No full textIn olive micropropagation, Copper (Cu) promotes metabolic activity at optimal levels but exerts toxic effects and induces stress and cellular damage when present at excessive concentrations. The present study examined in vitro olive (cv. Moraiolo) shoot cultures under varying Cu concentrations to evaluate the impact of Cu-induced stress on shoot growth and development, as well as the associated physiological and biochemical tolerance mechanisms. Olive shoots were cultured on OM medium (as a control) supplemented with 50, 100, 200, or 300 mu M CuSO45H2O. Morphological and biochemical analyses showed that up to 50 mu M Cu did not cause visible stress symptoms or impair growth, while higher concentrations (100-300 mu M) significantly suppressed or inhibited vegetative growth, and caused a marked reduction in photosynthetic pigments. The contents of oxidative stress markers, hydrogen peroxide and malondialdehyde, increased with rising Cu concentrations, serving as reliable indicators of severe stress conditions. Non-enzymatic antioxidants, glutathione, ascorbic acid and proline, increased with higher Cu concentrations, playing a protective role against oxidative damage. These findings provide insight into the tolerance mechanisms of olive shoots under Cu stress, offering useful information for optimizing in vitro micropropagation and understanding Cu toxicity in plant tissue culture
Induced drought affects morphological and eco-physiological response of Mediterranean wild roses
No full textWater scarcity for the irrigation of ornamental crops is a typical phenomenon of nursery activities in the south Mediterranean districts and has frequently detrimental effects on plant growth, yield and quality. Wild roses are generally hardy plants with high ornamental potentialities and possible tolerance to the main abiotic stresses typical of their native environments. Therefore, a greenhouse experiment was carried out with the aim to evaluate growing and qualitative response of two Sicilian rose species to increasing deficit irrigation. Rooted-cuttings plants of Rosa canina L. and R. sempervirens L. were grown in 4-L plastic containers under drought stress induced by progressively reducing the irrigation volumes (900, 600 and 300 mL plant-1) during each irrigation. Morphological and eco-physiological parameters were measured throughout the experiment. Increasing irrigation deficit resulted in a decrease of plant growth (at canopy and root level), ornamental effect, biomass yield and partitioning, stem water potential, leaf net photosynthesis and transpiration; this behavior was more evident in R. canina than in R. sempervirens potted plants. The identification of wild roses tolerant to moderate drought may allow to use them for ornamental nursery production and for landscaping in south Mediterranean areas often characterized by a low availability of the irrigation water
Allometric model for leaf area estimation in Bougainvillea genotypes.
No full textAccurate estimates of leaf area (LA) are an urgent need for modeling eco-physiological processes within urban greening. LA can be measured by direct or indirect methods. The direct methods are fast, but require leaf excision and it is therefore not possible to make sequential measurements. An alternative tool would be to develop allometric models that relate the individual LA to the linear measurements of leaf length (L) and maximum width (W). The development of an unbiased allometric model from linear measurements to predict individual LA of Bougainvillea irrespective of genotypes is still lacking. The models were built using LA, L, and W data measured in 600 leaves collected from four Bougainvillea genotypes: B. glabra LSQUOCrimson LakeRSQUO, B. spectabilis LSQUOLady WilsonRSQUO, LSQUOMary PalmerRSQUO and LSQUORubianaRSQUO. Model validation was performed on 150 Bougainvillea leaves collected from another genotype (B. spectabilis LSQUOFucsia colorRSQUO). LA prediction models based only on L or W measurements were not suitable for estimating LA of Bougainvillea. A linear model having the product L×W as independent variable (LA = -1.36 +0.63 LW) provided the most accurate estimate highest r2 (0.95), smallest MSE, smallest prediction sum of squares (PRESS), and to the reasonably close PRESS value to error sum of squares. In the model validation, correlation coefficients showed that there was a highly reliable relationship between the predicted and the observed LA values with an underestimation of 3.7%. The LA model using L×W as independent variable can be successfully adopted in research on Bougainvillea, since it provides an accurate, simple non-destructive estimation of LA across Bougainvillea genotypes avoiding the use of any expensive device such as electronic leaf area meters and plant canopy analyzers
- …
