Foliar Applications of Biostimulants Promote Growth, Yield and Fruit Quality of Strawberry Plants Grown under Nutrient Limitation

Abstract

Biostimulants have been found effective in enhancing plant resistance toward stressful conditions. The aim of the present study was to evaluate the efficacy of selected biostimulants to overcome the negative effects of nutrient limitation on the growth performances and on the fruit quality of soilless cultivated strawberry plants. The condition of nutrient limitation was imposed by supplying the plants with only a single fertilization at transplantation and by excluding any further nutrient supply for the entire duration of the experiment (three months, from May to July). Strawberry plants were treated seven times during the period from preflowering up to berry maturation with different classes of biostimulants (humic acids, alfalfa hydrolysate, macroseaweed extract and microalga hydrolysate, amino acids alone or in combination with zinc, B-group vitamins, chitosan, and a commercial product containing silicon) at commercial dosages. The use of alfalfa hydrolysate, vitamins, chitosan, and silicon was able to promote biomass accumulation in roots (four to seven folds) and fruits (+20%) of treated plants, whereas the total leaf area increased by 15%–30%. Nutrient concentrations in leaves and roots showed variations for microelements (e.g., Fe, B, Zn, and Si) in response to biostimulant applications, whereas no significant differences were observed for macronutrient contents among treatments. Final berry yield was found around 20% higher in chitosan- and silicon-treated plants. Chitosan treatment significantly increased pulp firmness (by 20%), while a high nutritional value (e.g., phenolic compounds concentration) was observed in alfalfa- and seaweed-treated fruits (+18%–20% as compared to control). The overall outcomes of the present experiment show that selected biostimulants can be considered as a valid agronomic tool able to contrast the negative consequence of growing crops under insufficient nutritional conditions.

Toward a Sustainable Agriculture Through Plant Biostimulants: From Experimental Data to Practical Applications

“…Similar results were also recorded in tomato fruits, where tropical plant extract and protein hydrolysates resulted in higher bioactive compounds (total phenols and vitamin C) and lipophilic antioxidant activity than those observed in the non-treated control [58]. Concerning berry fruits, Soppelsa et al [59] investigated the application of ten commercial biostimulants belonging to almost all the categories including: alfalfa hydrolysate, humic acids, macro-seaweed, extract and microalgal hydrolysate, amino acids alone or in combination with micronutrient (zinc), B-group vitamins, chitosan and a commercial product containing silicon. Biostimulant products based on chitosan had a major impact on strawberry pulp firmness, whereas biostimulant products based on alfalfa hydrolysate, macro-seaweed extract and microalgal hydrolysate induced an improvement in phenolic compounds compared to the remaining treatments.…”

Winter Pruning: Effect on Root Density, Root Distribution and Root/Canopy Ratio in Vitis vinifera cv. Pinot Gris

“…Similarly, root number/yield ratio was higher in P than in NP, in 2011 and 2012, due to the greater number of roots and the lower yield in P. In the same way, the evidence is that in NP there were more clusters and a higher yield/vine compared to P. The weight of the clusters was lighter in NP. This explanation is given because the production of roots is related to the reproductive allocation [51], the products of photosynthesis allocated in reproductive organs limits root growth; the general result is a higher yield and a lower root growth, in NP. This is also explained by the fact that the ability of the vines to produce dry matter is difficult to improve, in terms of absolute amount, through management practices [52].…”

Chitin- and Chitosan-Based Derivatives in Plant Protection against Biotic and Abiotic Stresses and in Recovery of Contaminated Soil and Water

“…cv. Elsanta 0.001% chitosan, foliar application Poor fertilization tolerance [41] For example, chitin added to the soil at the beginning of the experiment induces water-stress tolerance in maize (Zea mays L.) plants grown under regulated deficit irrigation [22]. Chitosan application has the potential to mitigate the water deficit effects on yield and quality of wheat (Triticum aestivum L.) [23], and in the same plant species chitosan nanoparticles decrease the adverse effects of drought stress [24].…”