Some Physiological and Biochemical Mechanisms during Seed-to-Seedling Transition in Tomato as Influenced by Garlic Allelochemicals

Abstract

The effects of aqueous garlic extracts (AGEs), diallyl disulfide (DADS), and allicin (AAS) were investigated during seed-to-seedling transition of tomato. Independent bioassays were performed including seed priming with AGE (0, 100, and 200 µg∙mL−1), germination under the allelochemical influence of AGE, DADS, and AAS, and germination under volatile application of AGE. Noticeable differences in germination indices and seedling growth (particularly root growth and fresh weights) were observed in a dose-dependent manner. When germinated under 50 mM NaCl, seeds primed with AGE exhibited induced defense via antioxidant enzyme activities (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)), lipid peroxidation (malondialdehyde content (MDA)), and H2O2 scavenging. Enzyme-linked immunosorbent analysis (ELISA) of the endogenous phytohormones auxin (IAA), abscisic acid (ABA), cytokinin (ZR), and gibberellic acid (GA3) in the roots and shoots of the obtained seedlings and the relative expression levels of auxin-responsive protein (IAA2), like-auxin (LAX5), mitogen-activated protein kinase (MAPK7 and MPK2), respiratory burst oxidase homolog (RBOH1), CHI3 and SODCC1 suggested allelopathic functions in stimulating growth responses. Our findings suggest that garlic allelochemicals act as plant biostimulants to enhance auxin biosynthesis and transportation, resulting in root growth promotion. Additionally, the relative expressions of defense-related genes, antioxidant enzymes activities and phytohormonal regulations indicate activation of the defense responses in tomato seedlings resulting in better growth and development. These results, thus, provide a basis to understand the biological functions of garlic allelochemicals from the induced resistance perspective in plants.

Hormone and carbohydrate metabolism associated genes play important roles in rhizome bud full‐year germination of Cephalostachyum pingbianense

“…Four major endogenous hormones (IAA, ZR, GA 3 , and ABA) in DR, GR, and GB samples of each season were measured by enzyme‐linked immunosorbent analysis (ELISA) (Hayat et al, 2020. Three biological replicas were used in each set of experiments.…”

Germination response of black nightshade (Solanum nigrum) to temperature and the establishment of a thermal time model

“…The calculations of the germinability, germination potential (Wei et al 2020), and germination index (GI) (Chen et al 2016;Hayat et al 2020;Zhou et al 2016) were as follows:…”

Induction of Catharanthus roseus Secondary Metabolites When Calotropis procera Was Used as Bio-Stimulant

“…Sizable research posted its phytotoxic effects, negative allelopathic potential and its role in weed control [ 11 , 12 ] while very limited works mentioned its nutritive and positive/stimulatory effect [ 13 ]. In the context, the active compounds from C. procera extract and their unique mode of action remain unknown due to the apparent multitude of potential molecular targets [ 12 ], performance overlapping and interaction between them [ 5 , 14 ], and their interference with the ecological factors regarding delivering method [ 15 ]. In our investigation, studying the impact of C. procera by using different types of extracts, ME, CWE and AWE (having different chemical natures) applied by two different modes, irrigation and foliar spraying (different contact surface, root and leaves), and identifying extracts composition may collectively present a clarification for the possibility to be used as bio-stimulant agent and mapping out how receiver plant could respond to them as well.…”