The sustainable management of weeds is one of the main challenges in agriculture. Recent studies have demonstrated the potential of plant phytotoxins, such as ailanthone from Ailanthus altissima (Mill) Swingle, as bioherbicides. Since a complex extract may be more active than a single compound, we explored the phytotoxicity of A. altissima extracts obtained from the leaves, samaras, rachises, and secondary roots, and we evaluated their application potential for weed control in horticulture. The pre-emergence activity of all plant extracts was evaluated over varying concentrations on two indicator species (i.e., Lepidium sativum L. and Raphanus sativus L.) under controlled conditions. As the leaf extract was able to be generated in sufficient quantities, it was therefore further evaluated in glasshouse experiments with seven common weed species as indicators, as well as in a nursery production system for the cultivation of three horticultural crops (i.e., Salvia officinalis L., S. rosmarinus Schleid., and Dianthus caryophyllus L.). Following the application of the extract, the index of germination (IGe%), the index of biomass, and the density of weeds per pot were evaluated, along with the impact on crop growth and quality (i.e., plant growth index and leaf damage). Under controlled conditions, the extract from the secondary root was the most active in reducing the IGe%, with greater persistence across time in both indicator species. At 18 days following application, the lowest concentration of the leaf extract at 1.8 mg L⁻¹ ailanthone reduced the IGe%by up to 15% and 45% in R. sativus and L. sativum, respectively. In R. sativus, all of the extract types affected the IGe%, but extract activity was greater in L. sativum. Under glasshouse conditions, leaf extracts containing 50 and 200 mg L⁻¹ ailanthone showed strong inhibition (98%–99%) in the biomass of all treated indicator and weed species. Under nursery conditions, leaf extracts formulated at 100 and 200 mg L⁻¹ ailanthone performed similarly, and no weeds were observed in any of the treated pots of S. officinalis and S. rosmarinus in the 60-day study period. Conversely, in the D. caryophyllus pots, an increase in the percentage of weed presence per pot was observed after 40 days. A reduction in the growth index and an increase in leaf phytotoxicity were observed during the cultivation experimentation, especially in S. officinalis when the extract was applied post-emergence to the crop canopy. Phytotoxicity was alleviated by the application of the extract directly to the soil or growth media. These results provide new insights into A. altissima extracts and their phytotoxicity to support their additional use as a sustainable solution for weed management in horticultural crops. Full article

Nowadays the heightened awareness of the critical trend in resource depletion impels to improve the eco − sustainability of any productive process. The research presented in this paper aims to quantify the environmental impact of the emerging productive process of edible flowers, focusing on two model species, i.e., Begonia x semperflorens − cultorum hort and Viola cornuta L., and two types of product, i.e., flowering potted plants sold in plastic vases and packaged flowers ready to be consumed. The study was carried out in an Italian nursery located in Tuscany, interviewing the owners in order to complete the Life Cycle Inventory, assessing the value of the impact categories, and using the “cradle to gate” approach. The information about the production of flowering potted plants and packaged flowers were inserted in a database and elaborated by the appropriate software. The results of the Life Cycle Assessment (LCA) analysis referred to 1 g of fresh edible flowers and were expressed in four impact categories. Global Warming Potential (GWP) values ranged from 24.94 to 31.25 g CO₂ eq/g flowers, Acidification Potential (AP) ranged from 8.169E − 02 to 1.249E − 01 g SO₂ eq/g flowers, Eutrophication Potential (EP) ranged from 3.961E − 02 to 5.284E − 02 g PO₄^{3 −} eq/g flowers, and Photochemical Ozone Creation Potential (POCP) ranged from 8.998E − 03 to 1.134E − 02 g C₂H₄ eq/g flowers. Begonias showed lower emissions than violas in the GWP and POCP indexes, whereas violas showed lower values in the AP and EP impact categories. The most impactful phase was the propagation, accounting on average for 42% of the total emissions. Overall, the findings highlighted a higher environmental load for the production of both begonias and violas packaged flowers, especially if in small containers, rather than as potted plants, with an emission percentage increase from 8% to 17% among the impact categories. Full article

The ornamental plant production in greenhouses is widespread. A quantitative assessment of greenhouse energy consumption and its variability in space and time is strategic to improve the sustainability of the cultivation. The specific environmental features of the cultivation areas can strongly affect the sustainability of the production. A dynamic simulation model of greenhouse energy balance with an hourly time step was developed and parameterized for a state-of-the-art greenhouse to evaluate the heating requirements for cut-flower roses. This ornamental crop has been used as model species for its high energy requirement for flower production. The energy demand for rose production has been analyzed with an energy balance model with an hourly time step. After a preliminary analysis on the period 1973–2019, the final analysis was carried out on the 30-year period (1990–2019), representative of the current climate. Results show a gradient southwest–northeast of energy needs with relevant effects on economic and environmental sustainability. More specifically, four large sub-areas are identified, namely the central-southern Mediterranean (yearly requirements below 600 MJ m⁻² year), the northern Mediterranean, and the area influenced by the mitigating effect of the Atlantic Ocean (600–1200), the central-European area (requirements of 1200–1800), and the Northern European area (above 1800). Full article

New solutions allowing for the shortening of the growing cycle and improvements in plant quality are constantly sought in order to improve the efficiency of bedding plant production under covers. Biodegradable polysaccharides and their derivatives have become increasingly popular in horticulture as plant growth promoters. A greenhouse pot experiment was conducted to evaluate the effects of depolymerized gellan of different molecular weights (M_W 56 kDa and 77 kDa) on the growth and physiological parameters of ornamental bedding plants Rudbeckia hirta L., Salvia splendens Sellow ex J.A. Schultes, Scabiosa atropurpurea L., and Tithonia rotundifolia (Mill.) S.F. Blake. The results showed that the application of depolymerized gellan accelerated flowering and stimulated the growth of all assessed species, regardless of M_W. The plants treated with depolymerized gellan grew higher and had greater fresh weight of their above-ground parts, higher leaf relative chlorophyll content (SPAD; soil and plant analysis development), and higher stomatal conductance (g_s). The use of 56 kDa gellan fraction resulted in the formation of inflorescences with the greatest fresh weight in S. atropurpurea. Leaves of R. hirta treated with this fraction showed the highest values of SPAD and g_s. This study demonstrated that gellan derivatives of low M_W may be used for the production of innovative plant biostimulants. Full article

Gazania rigens L. is a perennial herbaceous plant that belongs to the Asteraceae family, widely used as bedding or ornamental potted plants. The environmental and economic sustainability of ornamental production can be enhanced using environmentally friendly bioregulators. A pot experiment was conducted to evaluate the influence of key bioregulators gibberellic acid ((GA₃) at 50, 100 or 150 mg L⁻¹), humic acid ((HA) at 100, 300 or 600 mg L⁻¹), and ascorbic acid ((AA) at 50, 100 or 200 mg L⁻¹)), on the growth, leaf gas exchange, and ornamental quality of G. rigens. The results indicated that plants treated with foliar applications of GA₃, HA, or AA exhibited higher plant fresh and dry biomass, plant height, leaf area, and leaf area ratio, root-shoot ratio, root-shoot mass fractions, and number of flowers, as well as the flowers display time. All bioregulator treatments enhanced the vegetative and floral characteristics of Gazania plants. The GA₃ was the most efficient at the concentration of 100 mg L⁻¹. The highest efficacy of HA and AA treatments was observed at the higher concentrations, 600 and 200 mg L⁻¹, respectively. These results were associated with higher photosynthetic rate (A), transpiration rate (E) as well as stomatal conductance (gs), and water use efficiency (WUE). In conclusion, the results suggest that foliar-applied bioregulators to Gazania are promising and represent sustainable strategies to enhance growth, flowering, and flower display time of Gazania plants. Full article

Aromatic plants are commonly produced for ornamental, cosmetic and medicinal purposes. Their morphological traits and the amounts and compositions of the volatile substances and essential oils (EOs) produced can be influenced by several factors, including the cultivation technique. In the present study, the influence of substrate composition on Lavandula angustifolia Mill. production was evaluated. In particular, substrates containing mixes of peat (P), green compost (C) and/or demolition aggregates (A) were tested in the following ratios: 70%:30% v/v, P:C; 70%:30% v/v, P:A; and 40%:30%:30% v/v, P:C:A. The P:C mixture allowed to obtain the best results in terms of survival rate, compactness of the plant and flower production. The P:C:A led to higher yields and better quality of EOs, with higher amounts of linalool, an important compound for medicinal uses. The volatiles and the blooming trend were not affected by the different cultivation substrates. Therefore, substrate composition in pot lavender cultivation can be regulated depending on the final use of the plant, successfully using locally sourced material in addition to peat. Full article

Today, high amounts of residual nitrogen are regularly being reported in the open field production of hardy nursery stock. In some cases, excessive fertilizers or side-dressings are applied when circumstances are not favorable for uptake. Aquatic as well as terrestrial ecosystems are sensitive to enrichment with nutrients, but growers also benefit when losses are avoided. In this study, the potential of proximal optical sensors to optimize nitrogen fertilization was investigated in four woody species: Acer pseudoplatanus L., Ligustrum ovalifolium Hassk., Prunus laurocerasus ‘Rotundifolia’ L. and Tilia cordata Mill. For three consecutive growing seasons, plants were grown under three different fertilization levels to generate different nitrogen contents. Plant growth and nitrogen uptake were monitored regularly and combined with sensor measurements including Soil Plant Analysis Development (SPAD), Dualex and GreenSeeker. Here, we show that optical sensors at the leaf level have good potential for assisting growers in the sustainable management of their nursery fields, especially if leaf mass per area is included. Nevertheless, care should be taken when plants with different leaf characteristics (e.g., wax-layer, color, and leaf thickness) are measured. When all measuring years were considered, high correlations (R² ≥ 0.80) were found between area-based foliar nitrogen content and its non-destructive proxy (i.e., chlorophyll)measured by Dualex or SPAD. Based on our results, we recommend a relative rather than absolute approach at the nursery level, as the number of species and cultivars produced is very diverse. Hence, knowledge of absolute threshold values is scarce. In this relative approach, a saturation index was calculated based on the sensor measurements of plants grown in a reference plot with an ample nitrogen supply. Full article

A mixture of red and blue light-emitting diodes (LEDs; at a ratio of 7:3, respectively) were used to analyze the effects of different photosynthetic photon flux densities (PPFDs) (40, 80, and 120 µmol m⁻² s⁻¹ hereafter known as LED 40, 80, and 120, respectively) on the micropropagation of Gerbera jamesonii Bolus shoots. The experiment also examined the effect of 6-benzyladenine (BA) in 1, 2.5, and 5 µM concentrations in the media. Biometrical observations and analyses of leaf morphometry and photosynthetic pigment content were conducted. Shoot multiplication increased with an increasing BA concentration. A PPFD of 80 µmol m⁻² s⁻¹ and 5 µM BA is suggested as efficient for shoot propagation and economically viable. LED 120 increased the leaf blade area and its width, and circularity and elongation ratios. The intensity of light did not affect the fresh weight, which increased at higher BA concentrations (2.5 and 5 μM). The dry weight content decreased with increasing cytokinin concentration; the greatest content was observed on media with 1 µM BA under PPFD 120 µmol m⁻² s⁻¹. LED 80 increased the photosynthetic pigments content in the leaves in comparison to the standard intensity of LED 40. Increased BA concentration raises the content of chlorophyll a. Full article