Biofertilizer and biostimulant properties of the microalga Acutodesmus dimorphus

Abstract

Microalgae represent a potential sustainable alternative for the enhancement and protection of agricultural crops. Cellular extracts and dry biomass of the green alga Acutodesmus dimorphus were applied as a seed primer, foliar spray, and biofertilizer, to evaluate seed germination, plant growth, and fruit production in Roma tomato plants. A. dimorphus culture, culture growth medium, and different concentrations (0, 1, 5, 10, 25, 50, 75, and 100 %) of aqueous cell extracts in distilled water were used as seed primers to determine effects on germination. Seeds treated with A. dimorphus culture and with extract concentrations higher than 50 % (0.75 g mL−1) triggered faster seed germination—2 days earlier than the control group. The aqueous extracts were also applied as foliar fertilizers at various concentrations (0, 10, 25, 50, 75, and 100 %) on tomato plants. Extract foliar application at 50 % (3.75 g mL−1) concentration resulted in increased plant height and greater numbers of flowers and branches per plant. Two dry biomass treatments (50 and 100 g) were applied 22 days prior to seedling transplant and at the time of transplant to assess whether the timing of the biofertilizer application influenced the effectiveness of the biofertilizer. Biofertilizer treatments applied 22 days prior to seedling transplant enhanced plant growth, including greater numbers of branches and flowers, compared to the control group and the biofertilizer treatments applied at the time of transplant. The A. dimorphus culture, cellular extract, and dry biomass applied as a biostimulant, foliar spray, and biofertilizer, respectively, were able to trigger faster germination and enhance plant growth and floral production in Roma tomato plants.

Biomass and physiology of papaya seedlings produced under leaf fertilization with Spirulina platensis

“…Garcia et al (2014) and Silva et al (2012), evaluating the effect of the extract of the microalgae Ascophyllum nodosum on cashew and cabbage (Brassica oleracea L.) seedlings, respectively, found that the concentrations of the extract did not influence the variable seedling height at the concentrations tested. Divergent results were obtained by Garcia-Gonzalez & Sommerfeld (2016), who studied the use of a biofertilizer based on the microalgae Dimorphus acutodesmus, where the foliar application of 3.75 g yielded a higher plant height in tomato (Solanum lycopersicum). Regarding the physiological variables, no significant effect was observed in the Spirufert® concentrations for leaf net photosynthesis (A), transpiration (E), stomatal conductance (Gs), internal CO2 concentration (Ci) and instantaneous efficiency of carboxylation (A/Ci).…”

Growth, yield, and postharvest quality in eggplant produced under different foliar fertilizer (Spirulina platensis) treatments

“…Because of the potential of microalgae for use in more sustainable production systems such as organic agriculture and biodynamic agriculture, a number of studies were conducted to evaluate the effect of microalgae fertilizers on different crops (ZODAPE et al, 2011;PAUDEL et al, 2012;SHALABY;EL-RAMADY, 2014;TARRAF et al, 2015;GARCIA-GONZALEZ;SOMMERFELD, 2015). Some of these studies have found a positive effect of microalgae fertilizers, especially when applied to leaves, in crops such as Allium sativum (SHALABY; EL-RAMADY, 2014), pepper (ALY; ESSAWY, 2008), rice (PAUDEL et al, 2012), and tomato (ZODAPE et al, 2011).…”

Microalgae biorefineries: applications and emerging technologies

“…This strategy has been useful and effective in achieving the increase in plant growth. In other studies, González et al (2016) took advantage of the residual water of the microalgae culture, and the cellular extracts obtained after cell disruption and the microalgal biomass was shown to increase germination rates, as well as growth and production of flowers of the tomato plant (Solanum lycopersicum) [100].…”

“…[98,101] Batista et al carried out various studies on the incorporation of microalgal biomass in different foods such as cookies, pasta and mayonnaise. For example, in one of their investigations, it was observed that the addition Chlorella vulgaris and Haematococcus pluvialis biomass with high carotenoid content increases the oxidative resistance of the mayonnaise lipids and has an emulsifying effect [99,100].…”