Salinity is well known to reduce plant growth and yield by reducing water availability; it does so by interfering with both nutrient uptake and translocation. The objective was to determine the nitrate and potassium contents in xylem sap and the root-shoot transportation of both as a function of the salinity of the nutritional solution provided. We compared NO 3 -and K + contents and flux in xylem sap collected from cut stems of tomato seedlings, based on electric conductivity (EC) tests among five nutrition solutionsfor soilless crops ranging from medium to high salinity. The EC was 2.2, 3.5, 4.5, 6 and 12 dS m -1 . The concentration of nitrates and potassium in the xylem sap remained constant, while the external concentration in the rhizosphere varied greatly. Notwithstanding, the xylematic flux was strongly affected by the salinity of the nutritional solution: at maximum salinity, EC reached 3.5 dS m -1 ; at minimum, EC was 12 dS m -1 . For similar reasons, the longest NO 3 -and K + transportation distance between root and shoot was achieved when the EC read 3.5 dS m -1 , but was reduced by up to 80% when EC was 12 dS m -1 .

Borage is a well-known plant of great importance in human nutrition and health. Expanding knowledge of particular plants that have anti-cancer products is a global concern. There is substantial information regarding the benefits, presence and extraction of gamma linolenic acid (GLA; 18:3n6) in different plants around the world, especially in borage seeds. However, there is little information concerning the effects of the salinity of the nutrient solution on the growth and presence of GLA in borage seeds. The objective of this work was to determine the optimal salinity of the nutrient solution for obtaining GLA in soilless cultivation systems. Borage plants were grown in coconut fibre and provided three treatments of nutrient solution of 2.20, 3.35 and 4.50 dS m -1 , increasing solution salinity with the standard nutrient solution of concentrated macronutrients as a reference. Vegetative growth, seed production and GLA ratio were measured. The results of vegetative development and GLA production doubled and tripled with the increase in salinity of the nutrient solution, respectively.

Plant quality and survival prediction tools are useful when applied in the field in different agricultural sectors. The objectives of this study were to conduct a review and bibliometric analysis of the Dickson Quality Index (DQI) as a key plant quality indicator and with respect to its scientific applications. A third objective was to identify the main morphological and physiological parameters used in plant production research. The methodology and findings of 289 scientific articles were analysed based on the morphological, physiological, and mathematical parameters used as plant quality indicators in research on forest, medicinal, horticultural, aromatic, and ornamental species. During the last 10 years, the number of publications that have used the DQI as a plant quality parameter has increased by 150%, and Brazilian researchers stand out as the most frequent users. Forestry is the discipline where quality parameters and their biometric relationships are most often used to facilitate intensive plant production. Use of the DQI increases the certainty of prediction, selection, and productivity in the plant production chain. The DQI is a robust tool with scientific application and great potential for use in the preselection of plants with high quality standards among a wide range of plant species.

The effect of pH and silicon (Si) in the nutrient solution on the vegetative development of 2-year-old blueberry plants (Vaccinium corymbosum L. cv. Ventura) was studied. Two independent experiments were performed on coir fiber (CF) and sand as substrates. In experiment 1, Si was applied in the nutrient solution at a dose of 0.0, 0.3, 0.6, and 1.2 mM. In experiment 2, plants were treated with nutrient solution at pH 4.00, 4.75, 5.50, and 6.25, using two sources of acidification: nitric acid and citric acid. The parameters of plant growth, foliar surface, and stem biomass were measured. With the application of 1.2 mM Si to CF, plant height registered a significant increase of 8%, and shoot dry and fresh biomass increased by 21% and 25%, respectively. The results of experiment 1 indicated that the application of Si benefits the vegetative growth of blueberry plants in CF, but no effect was observed in the sand substrate. In the results of experiment 2, the pH level of 6.25 in CF decreased the dry weight of stems and leaves by 21% and 18%, respectively. A significant increase in the pH range of 4.00 to 5.50 was recorded in both the citric acid and nitric acid treatments, but these significant effects were not found in sand. Citric acid presented a similar behavior to nitric acid, which indicates that it can be a good source of acidification in organic and ecologically friendly crops.

Rocket salad is an important vegetable for the ready-to-eat sector, normally cultivated under greenhouse conditions, either in soil or soilless systems. In the latter case, as well as in the nurseries, its cultivation is usually carried out by using peat as a growing medium—a non-renewable substrate—for which it is urgent to find a replacement. Similarly to peat, compost may be used as a growing medium; however, depending on its origin, the chemical and physical characteristics may not bet suitable for plants’ cultivation. In this study, we propose the use of agro-industrial compost as a substitute for peat for rocket salad cultivation. Plants grown in compost, alone or in combination with the second cut of rocket salad, gave better results in several biometric parameters, without negatively affecting yield and dry weight percentage. As a mechanistic approach to further understand how compost can affect plants’ stress, the qualitative profile of phytochemicals (glucosinolates and (poly)phenols)—recognized markers of biotic and abiotic plant stress—were monitored and exhibited a decreasing trend in plants grown using compost relative to those cultivated with peat. The analysis of vitamin C provided information on the achievement of an enhanced concentration by the compost, especially in the second cut. It can be inferred from the results obtained that the compost used as a growing medium may be used as a peat-free substrate for rocket crop cultivation.