Search

Vegetable plants are more sensitive to salt stress during the early growth stages, hence, the availability of poor-quality brackish water can be a big issue for the nursery vegetable industry. Microbial biostimulants promote growth and vigor and counterbalance salt stress in mature plants. This study aimed to evaluate the application of plant growth-promoting microorganisms for improving salt tolerance of lettuce and tomato seedlings irrigated with different water salinity levels (0, 25, and 50 mM NaCl) during nursery growth. Two commercial microbial biostimulants were applied to the substrate before seeding: 1.5 g L−1 of TNC BactorrS13 containing 1.3 × 108 CFU g−1 of Bacillus spp., 0.75 g L−1 of Flortis Micorrize containing 30% of Glomus spp., 1.24 × 108 CFU g−1 of Agrobacterium radiobacter, Bacillus subtilis, Streptomyces spp. and 3 × 105 CFU g−1 of Thricoderma spp. Many morpho-physiological parameters of lettuce and tomato seedlings suffered the negative effect of salinity. The use of the microbial biostimulants modified seedling growth and its response to salt stress. They had a growth-promoting effect on the unstressed seedlings increasing fresh and dry biomass accumulation, leaf number, and leaf area and were successful in increasing salinity tolerance of seedlings especially when using Flortis Micorizze that enhanced salinity tolerance up to 50 mM NaCl. The inoculation of the substrate with microbial biostimulants could represent a sustainable way to improve lettuce and tomato transplant quality and to use brackish water in vegetable nurseries limiting its negative effect on seedling growth.

Seed germination and early seedling growth are the plant growth stages most sensitive to salt stress. Thus, the availability of poor-quality brackish water can be a big limiting factor for the nursery vegetable industry. The exogenous supplementation of gibberellic acid (GA3) may promote growth and vigor and counterbalance salt stress in mature plants. This study aimed to test exogenous supplementation through foliar spray of 10&minus, 5 M GA3 for increasing salt tolerance of tomato and sweet pepper seedlings irrigated with increasing salinity (0, 25, and 50 mM NaCl during nursery growth. Tomato and sweet pepper seedlings suffered negative effects of salinity on plant height, biomass, shoot/root ratio, leaf number, leaf area, relative water content, and stomatal conductance. The foliar application of GA3 had a growth-promoting effect on the unstressed tomato and pepper seedlings and was successful in increasing salinity tolerance of tomato seedlings up to 25 mM NaCl and up to 50 mM NaCl in sweet pepper seedlings. This treatment could represent a sustainable strategy to use saline water in vegetable nurseries limiting its negative effect on seedling quality and production time.

Plant growth-promoting rhizobacteria have been applied to different vegetable crops but there is still no information on the effect of bacterial biostimulant application under variable nutritional level on lettuce seedlings and their performance after transplanting in the field. This study aimed to evaluate the efficacy of a bacterial biostimulant to enhance growth and quality of lettuce seedlings fertigated with increasing nutrient rates and to assess the efficacy of these treatments on lettuce head production. Lettuce seedlings were inoculated with 1.5 g L&minus, 1 of TNC BactorrS13 (a commercial biostimulant containing 1.3 &times, 108 CFU g&minus, 1 of Bacillus spp.) and fertigated with a nutrient solution containing 0, 1, 2, and 4 g L&minus, 1 of NPK fertilizer (20-20-20). At the end of transplant production, the plants were evaluated for greenhouse cultivation. The effect of fertigation rate on seedling height, dry biomass, dry matter percentage, and water use efficiency was evident up to 2 g L&minus, 1 of fertilizer in the non-inoculated seedlings, whereas fresh biomass and nitrogen use efficiency changed up to 4 g L&minus, 1 of fertilizer. The use of the bacterial biostimulant modified seedling growth and its response to nutrient availability. The inoculation of the substrate with Bacillus spp. promoted plant growth and allowed seedlings to reach the highest height and biomass accumulation. The physiological age of lettuce seedlings showed a strong influence on plant growth and production after transplanting. The bacterial treatment positively affected the yield and nitrate content of lettuce plants.

Ecklonia maxima is a brown algae seaweed largely harvested over the last years and used to produce alginate, animal feed, fertilizers, and plant biostimulants. Their extracts are commercially available in various forms and have been applied to many crops for their growth-promoting effects which may vary according to the treated species and doses applied. The aim of the study was to characterize the effect of adding an Ecklonia maxima commercial extract (Basfoliar Kelp, 0, 1, 2, and 4 mL L−1) to the nutrient solution of a hydroponic floating system on growth, yield, and quality of leaf lettuce at harvest and during cold storage (21 days at 4 °C). The supplementation of the E. maxima extract through the mineral nutrient solutions, especially between 2 and 4 mL L−1, enhanced plant growth and improved the yield and many morphological and physiological traits (biomass accumulation, leaf expansion, stomatal conductance, water use efficiency, nitrogen use efficiency, etc.). Preharvest treatments with E. maxima extract were effective in delaying leaf senescence and extending the shelf-life of fresh-cut leaf lettuce. The delay in leaf decay of treated samples allowed to retain an overall quality over the threshold of marketability for up to 21 d of cold storage, especially using 2 mL L−1 of extract.

Mediterranean areas with intensive agriculture are characterized by high salinity of groundwater. The use of this water in hydroponic cultivations can lead to nutrient solutions with an electrical conductivity that overcomes the tolerance threshold of many vegetable species. Plant growth-promoting rhizobacteria (PGPR) were shown to minimize salt stress on several vegetable crops but the studies on the application of PGPR on leafy vegetables grown in hydroponics are rather limited and have not been used under salt stress conditions. This study aimed to evaluate the use of plant growth-promoting bacteria to increase the salt tolerance of leaf lettuce grown in autumn and spring in a floating system, by adding a bacterial biostimulant (1.5 g L&minus, 1 of TNC BactorrS13 a commercial biostimulant containing 1.3 &times, 108 CFU g&minus, 1 of Bacillus spp.) to mineral nutrient solutions (MNS) with two salinity levels (0 and 20 mM NaCl). Leaf lettuce plants showed a significant reduction of growth and yield under salt stress, determined by the reduction of biomass, leaf number, and leaf area. Plants showed to be more tolerant to salinity in autumn than in spring. The inhibition of lettuce plant growth due to salt stress was significantly alleviated by the addition of the bacterial biostimulant to the MNS, which had a positive effect on plant growth and fresh and dry biomass accumulation of the unstressed lettuce in both cultivation seasons, and maintained this positive effect in brackish MNS, with similar or even significantly higher values of morphologic, physiologic, and yield parameters than those recorded in control unstressed plants.

Solanum torvum is the eggplant ( Solanum melongena ) relative most commonly used for grafting even if the nursery production of eggplants grafted onto this rootstock has some issues related to its long, irregular and erratic germination and slow growth and development of seedlings. Unrooted cuttings harvested from stock plants could be an alternative propagation material to obtain S. torvum rootstocks and might allow to overcome nursery production issues for eggplant. The aim of this work was to evaluate eggplant suitability to be propagated by unrooted grafted cuttings using S. torvum as rootstock and the influence of this propagation technique on plant yield and fruit quality. A two years trial was performed in nursery and open field. The eggplant cultivar Birgah was used as the scion variety as well as the ungrafted controls (seedling control and unrooted cutting control). Two propagation techniques of the rootstock were evaluated using S. torvum and ‘Birgah’ eggplant (self-grafted): unrooted cuttings or seedlings. S. torvum showed to be suitable to be propagated by unrooted grafted cuttings. The joined healing and rooting had no negative effect on grafting success and plantlets quality. The use of unrooted cuttings of S. torvum , instead of seedlings, reduced considerably the length of propagation time. The shorter propagation time of the innovative propagation technique might permit propagators to overcome the propagation issues of S. torvum and to optimize the scheduling for grafted eggplant production. The use of S. torvum rootstock for grafting eggplant confirmed to enhance plant vigour and productivity. The plants produced from unrooted grafted cuttings of S. torvum showed no differences with the traditional grafted plants in field trials as regard fruit yield and quality. Thus, this innovative technique may be feasible for nursery and field production.

Borage (Borago officinalis L.) is a wild vegetable appreciated as a folk medicine and for culinary preparations. The introduction of borage as a specialized cultivation would allow for the diversification of vegetable crops and would widen the offerings of raw and minimally processed leafy vegetables. Thus, the aim of the research was to evaluate the quality and shelf-life of fresh-cut borage stored at different temperatures. Borage plants were grown during the autumn&ndash, winter season and immediately minimally processed after harvest. Fresh-cut borage leaves packed in sealed bags were stored at 2 or 6 &deg, C for 21 d. Weight loss, total soluble solids (TSS), titratable acidity (TA), ascorbic acid, nitrates, leaf color characteristics and overall quality were determined through the storage period. Borage plants were deemed suitable for minimal processing. Storage temperature significantly influenced the rate of quality loss. Borage leaves had an initial nitrate content of 329.3 mg kg&minus, 1 FW that was not affected by temperature or storage. TSS and TA were higher in leaves stored at 6 &deg, C. TSS, TA and ascorbic acid content increased during storage. Minimally processed borage leaves stored at 2 &deg, C had lower weight loss and leaf color modifications during storage and a longer shelf life than those stored at 6 &deg, C, so were still marketable after 21 d of storage.

Collard greens (Brassica oleracea var. acephala) are a group of plants cultivated for its thick, slightly bitter, edible leaves. As other Brassicaceae, have a good nutritional value as they are a good sources of vitamin C and soluble fiber, and contain various compounds with potent anticancer properties. In order to enhance collard cultivation in Sicily, different planting dates were tested. The research was carried out during 2009-2010 in the experimental field of SAgA Department – University of Palermo. Plants of a Sicilian local cultivar, with high vigor, good emission of side shoots, large and moderately curly leaves and long and strong petiole, were planted in three different periods: end of November, end on January, end of March. The harvest of the main shoot was made when they had tender and non-fibrous leaves and petioles. Secondary shoots, eventually originated from axillary buds left on the plant, were also harvested. Data were recorded on: number of leaves plant-1, stem diameter, fresh weight, dry weight, length and number of harvested shoots. The plants of the earliest transplant were harvested in March (main shoot), April and May (secondary shoots), while only the main shoot was harvested in the other plants (on May and June respectively for the second and the third transplant). This determined an higher yield for the first transplant against the other planting dates. Early transplant influenced also the quality of the main shoots that had more leaves, higher percentage of edible part and less dry matter than those from the other transplant. Secondary shoots had worst quality than the main shoot.

In the southern regions of Mediterranean areas the plantations with fresh plants (winter planting system) have almost completely replaced those with cold stored plants (summer planting system). Particularly, fresh bare root plants produced in high elevation nurseries located in Spain and Poland and, in experimental phase, in the southern of Italy (in the mountains of Sicily, Calabria, Basilicata) are the most used. Such type of plant usually has a crown diameter from 6 to 14 mm, but the smallest plants should be (

The floating system is an inexpensive and easy hydroponic system. It can be used to produce small-size leafy vegetables or ready-to-use vegetables that are raising more and more interest among consumers. The aim of this study was to evaluate the effects of different salinity of nutrient solution and of water supply before the harvest, on rocket (Eruca sativa L.) plants hydroponically grown using the floating system technique. The growing cycle was carried out in greenhouse in march-april 2002. Two nutrient solutions with different electrical conductivity (2.8 and 3.8 mS cm-1) were compared. Both solutions had the same nutrient composition and the differences in EC were obtained using water with different salinity (ECw 0.8 and 1.6 mS cm-1). Five days before harvest, half of the floating boards were supplied only with water instead of nutrient solution, in order to evaluate the effect of this treatment on leaf nitrate content. Data were collected on plant height, leaf area, yeald and the ratio and content in the plant of anions and cations. The rocket shows a good adaptability to this growing system. EC levels tested have not affected the plant height and slightly influenced the yield. The water treatment before harvest, resulted in higher yeald and lower nitrate concentration.

The ban of methyl bromide and the need for low environmental impact of agriculture has recently increased the interest in the biofumigant effects of Brassica species on soil-borne pathogens. Many researches have tested the toxic effects of Brassica green manures on several soil-borne pathogens in vitro, but field studies have not assessed definitely the efficiency of biofumigation at the field scale and the effect on crop development and production quality. The aim of this research was to evaluate the effect of a winter-spring cover crop of Brassica juncea compared to bare soil on a mono-succession of melon. The biomass of the B. juncea plants or of the weeds eventually developed in bare soil, used as control, were managed as follows:(i) crushed and left on the soil as organic mulching; (ii)crushed and incorporated into the soil; (iii) crushed and incorporated into the soil under PE mulching along melon crop rows. Soil changes during the two years trial were monitored by evaluating: organic matter content, availability and content of mineral elements and Cation Exchange Capacity. Marketable and unmarketable production, fruit weight and fruit quality (thickness of the epicarp and pulp, percentage of edible part, soluble solid content, firmness, etc.) were evaluated on melon. The use of Brassica juncea as a cover crop influenced soil characteristics and was effective on melon compared to bare soil when the biomass was incorporated to the soil, while no difference was found on melon production and quality when PE mulching was used.

Eggplants have fruits with different sizes, shapes and colours, according to the cultivar. Skin colour is due to anthocyanins, pigments located in the cell vacuole of fruit skin that belong to phenolic flavonoids, a powerful antioxidants group. Environmental conditions and growing techniques may influence fruits characteristics and their content of phenolic compounds. Grafting is a non chemical alternative for overcoming the effects of intensive and continuous cropping. The rootstocks preferred for eggplant are hybrids of tomato or tomato KVFN. Also species taxonomically close, as Solanum torvum, have been used and showed good vigour, compatibility and resistance to wilt disease. Information on yield and quality of grafted eggplants onto this rootstock is conflicting. Therefore, the aim of this study was to evaluate yield and quality of eggplant cultivars (‘Birgah’, ‘Black Bell’, ‘Black Moon’ and ‘Longo’) grafted or ungrafted onto Solanum torvum. Plants were grown in an unheated plastic greenhouse from October 2009 till May 2010. Grafted plants had lower mortality, while yield and quality of fruits were mostly influenced by cultivars. Differences among tested cultivars in growth characteristics, graft affinity and compatibility, could have caused the variations observed in growth and yield. ‘Longo’ and ‘Black Moon’ were not influenced by grafting, while grafted plants of ‘Birgah’ and ‘Black Bell’ had a higher portion of unmarketable production. Grafting onto Solanum torvum did not change the colour saturation of berries, with the exception of 'Birgah' that, when grafted, produced fruits with a less vivid colour. Also inner tissue browning was not influenced by grafting. Total phenolic content was greater in the ungrafted plants.