Search

The aim of this work was to study the influence of salinity of the fertigation solution on the vegetative growth, as well as on the osmolytes and chloride concentration of four halophytic species. ...

Plant growth is limited by salinity stress. There are few strategies for alleviating it although Arthrospira platensis and silicon can stimulate plants to grow under stress conditions. The aim of this work was to study the effects of both a single and a joint application of Arthrospira platensis and silicon on the growth of Pelargonium hortorum L.H. Bailey under salt stress conditions. Plants were exposed to 2.0, 3.0, and 3.5 dS m&minus, 1 EC (electrical conductivity), with and without the application of microalgae and silicon. At the end of the trial, the biometric parameters and the plant analysis were determined. The microalgae hydrolysate concentration was 5 g L&minus, 1 and the silicon concentration was 150 mg L&minus, 1. Foliar spraying was applied weekly. Pelargonium can be grown in moderately saline irrigation water (3.0 dS m&minus, 1). This bedding plant mitigates salt stress by avoiding the uptake of Cl&minus, ions and by tolerating a high Na+ concentration in the tissue. The joint foliar application of Arthrospira microalgae and silicon stimulates root, shoot, leaf, and flower formation in the Pelargonium hortorum L.H. Bailey crop under salinity conditions (3.5 dS m&minus, 1).

Salinity is one of the environmental factors inhibiting productivity in crop plants. Available strategies to mitigate the abiotic stresses are limited. Microalgae and cyanobacteria can mitigate the adverse effects of abiotic stress due to their biostimulant properties. The aim of this work was to study the effect of hydrolysate of the ciyanobacterium Arthrospira platensis on the growth of Petunia plants under salt stress conditions over two growing seasons (winter and spring). Plants were exposed to 2.0, 2.5, and 3.0 dS m−1 EC, with and without application of A. platensis hydrolysate. At the end of the trial, biometric parameters and plant analysis were determined. Petunias had a negative response when the salinity level rose from 2 to 3 dS m−1 and exhibited moderate tolerance to high internal Na and Cl concentrations. Results show that a high salinity reduces the Ca, Mg, K, and S contents in the leaves and provokes a sharp reduction in the K+/Na+ relationship. Applying A. platensis hydrolysate alleviates the effects of NaCl stress and stimulates shoot and bud formation in the petunia mother plant while inducing flowering in commercial Petunia plants. The A. platensis hydrolysate application increased the K+/Na+ relationship in treatments with an EC of 3.0 dS m−1.

The objective of this work is the development of empirical models that permit the prediction of the calcium (Ca) and magnesium (Mg) nutritional needs of Dieffenbachia amoena “Tropic Snow.” In order...

The sequential reuse of drainage water in greenhouse horticulture production to grow successively more salt tolerant crops is proposed as a sustainable alternative to recirculation systems when the irrigation water quality is low. This practice is known as Serial Biological Concentration or Integrated Farm Drainage Management. The objective of this assay was to assess the nutritional responses of Cordyline fruticosa var. ‘Red Edge’ (a semi-tolerant crop) fertigated with leachates from Citrullus lanatus (horticultural crop) cultivated on rockwool, compared to a conventional fertigation. Four treatments were tested: T1 (nutritionally balanced control or standard nutrient solution, with an electrical conductivity (EC) of 2.5 dS m−1); T2 (saline control; T2 diluted to an EC of 1.5 dS m−1, afterwards, NaCl was added to achieve 2.5 dS m−1); T3 (pure leachate from the hydroponic culture of C. lanatus), and T4 (diluted leachates, T3 diluted with irrigation water to 2.5 dS m−1). At the end of the trial, biometric parameters were determined and Na+, K+, Ca2+ and Mg2+ concentrations and the accumulation in photosynthetic organs (leaves), conductive organs (stems and petioles) and absorption organs (roots) were measured. The treatments tested had no effect on the number of leaves, leaf area per plant, leaf size, plant fresh and dry weight and shoot:root dry weight ratio. Nevertheless, the plants fertigated with pure leachates were significantly smaller. Regarding the plants’ fresh:dry weight ratio, this was significantly lower when plants were fertigated with pure leachates than with diluted leachates. The use of pure leachates does not cause an increment in total Na+ accumulation with respect to the nutritionally balanced control because Na+ concentration increases only in stems and petioles. Total K+ accumulation decreased when plants were irrigated with solutions with high concentrations of NaCl. The high Ca2+ concentration in the non-diluted leachate led to a high total Ca2+ accumulation. Total Mg2+ accumulation was affected negatively by Ca2+ uptake. It can be concluded that diluted leachates from C. lanatus can be used for the fertigation of C. fruticosa.

In closed soilless growing systems, leachates are used for the fertigation of the same culture, which is known as recirculation. This technology has been widely studied. It constitutes an environmentally friendly system because it prevents the leaching of chemicals into the environment, contributing to the sustainability of the horticultural sector. Nevertheless, the use of low quality water makes its application difficult. Moreover, as salinity increases in leachates, specific ions may become toxic or interfere with the uptake of other nutrients. In these situations, the sequential reuse of drainage waters to grow successively more salt tolerant crops, a practice which is known as Serial Biological Concentration or Integrated Farm Drainage Management, may be proposed. The aim of this trial was to assess the nutritional responses of Cordyline fruticosa var. ‘Red Edge’ (a semi-tolerant crop) fertigated with leachates from Citrullus lanatus cultivated on rockwool, compared with to conventional fertigation. There were 4 treatments: T1 (nutritionally balanced control or standard nutrient solution, with an electrical conductivity (EC) of 2.5 dS m−1), T2 (saline control; T2 diluted to an EC of 1.5 dS m−1; afterwards, NaCl was added to achieve 2.5 dS m−1), T3 (pure leachates from the hydroponic culture of C. lanatus) and T4 (diluted leachates, T3 diluted with irrigation water to 2.5 dS m−1). Dry weight (DW) and Cl−, N, P and SO42− concentrations as well as the extraction of photosynthetic organs (leaves), conductive organs (stems and petioles) and absorption organs (roots) were measured. The results obtained confirmed that diluted leachates can be employed for the fertigation of C. fruticosa ‘Red Edge’, because there were no effects on the plants DW, and no significant differences in Cl−, N, P or SO42− concentrations in leaves with respect to the nutritionally balanced control.

In horticultural practice accelerated plant development and particularly earlier flowering, has been reported with microalgae applications. Therefore, the objective of this work was to study the effects of foliar spraying with Scenedesmus sp. and Arthrospira platensis hydrolysates on Petunia x hybrida plant development and leaf nutrient status. Three treatments were tested: T1 (foliar application with water, the control), T2 (foliar application with Arthrospira), and T3 (foliar application with Scenedesmus). Foliar spraying was applied five times (0, 14, 28, 35, and 42 days after transplanting). The concentration of both microalgae was 10 g L−1. At the end of the trial biometric parameters and nutrient concentration in photosynthetic organs (the leaves) were measured. The results of this assay show that foliar application of Scenedesmus accelerated plant development in terms of higher rates of root growth, leaf and shoot development, and earliness of flowering. Arthrospira enhanced the root dry matter, the number of flowers per plant, and the water content. Nevertheless, a reduction was found in the conductive tissue (stem + petiole) dry weight with Arthrospira compared with Scenedesmus and the control. The results also show that microalgae hydrolysate supply can improve the plant nutrient status. Based on these results, it is advisable to use Scenedesmus hydrolysates in foliar applications to increase the blooming of Petunia x hybrida.