Effect of Biostimulants on Leafy Vegetables (Baby Leaf Lettuce and Batavia Lettuce) Exposed to Abiotic or Biotic Stress under Two Different Growing Systems

Abstract

Plant biostimulants are substances or microorganisms aimed at promoting plant growth by increasing the mineral nutrition efficiency, tolerance to environmental stress, and crop quality traits. This new category of crop inputs has been capturing the interest of both researchers and agriculture takeholders in light of the promising effects they could have on crop productivity and sustainability. This study investigated a variety of biostimulants for their effect on germination rates, plant health, chlorophyll fluorescence parameters, SPAD index, and growth of baby leaf lettuce and Batavia lettuce submitted to biotic (absence/presence of Pythium ultimum in the growing medium) or abiotic (0, 40, 80, and 120 mM NaCl L−1 concentrations and −0.5, −2, −4, and −6 kPa water potentials) stresses when grown in a greenhouse under conventional and organic cultivation. The results obtained show that lettuce response to biostimulants was influenced by the type or level of stress applied and the growing system used. The effects of the tested biostimulants varied from strongly detrimental to strongly beneficial.

Phytohormone-Based Biostimulants as an Alternative Mitigating Strategy for Horticultural Plants Grown Under Adverse Multi-Stress Conditions: Common South African Stress Factors

“…Phytohormones, namely auxins, CKs, GAs, auxins, brassinosteroids (BRs), and ethylene (ET) are categorized under plant growth regulators and ABA, Jasmonic acid (JA) and SA as bio-inhibitors (Chen et al, 2016;Iqbal et al, 2020;Jiménez-Arias et al, 2022;Verma et al, 2022;Wei et al, 2023). Phytohormones can induce an array of physio-biochemical processes and control the transcription of genes for adaptive plant responses to abiotic and biotic stresses (Nephali et al, 2020;Turan et al, 2021;Rana et al, 2022;Clément et al, 2023). Some plant hormones are essential biostimulant compounds used by the crop and horticultural industries (Tadele and Zerssa, 2023).…”

The Influence of Humic Acids and Nitrophenols on Metabolic Compounds and Pesticide Behavior in Wheat under Biotic Stress

“…Amiri et al [8] determined a decrease in photosynthetic dyes and improvements in phenolic compounds, flavonoids, and carbohydrate levels in potato under exposure to different types of pesticides: abamectin (I), cymoxanil (F), and metribuzin (H). As agents supporting the health of the target plant, biostimulators can mitigate the adverse effects of oxidative stress [9]. An organic biostimulator based on Ascophyllum nodosum seaweed extract caused an increase in the level of photosynthetic dyes and carbohydrates in tomato leaves under drought stress [10].…”