Biologically Active Organic Compounds, Especially Plant Promoters, in Algae Extracts and Their Potential Application in Plant Cultivation

Algae biostimulants: A critical look at microalgal biostimulants for sustainable agricultural practices

“…Table 1 3.1.1 Auxins: Examples of auxins include indole-3-acetic acid (IAA), 4-chloroindole-3-acetic acid (ClIAA), indole-3-butyric acid (IBA) and 2-phenylacetic acid (PAA) (Górka et al, 2015). Auxins are reported to be found in brown algae (Macrocystis, Laminaria), green algae (Klebsormidium nitens, Acutodesmus obliquus, C. vulgaris, Chlorella pyrenoidosa, S. quadricauda and charophyte, Cladophora, Enteromorpha) and red algae (Botryocladia) (Liu et al, 2016;Ohtaka et al, 2017;Pan et al, 2019;Piotrowska-Niczyporuk et al, 2018;Tarakhovskaya et al, 2007) (Table 1).…”

“…was more effective due to higher concentrations of IAA (5965 ng g −1 ) (Table 2) and abscisic acid (3718.25 ng g −1 ) (Table 3) (Plaza et al, 2018). 2,4-dichlorophenoxyacetic acid is a widely used synthetic auxin in agricultural practices to mimic the actions of IAA, however, constant use leads to accumulation in the environment which can be detrimental to the treated plants (Górka et al, 2015).…”

“…Algal cytokinins include zeatin, zeatin riboside, kinetin, isopentenyladenosine (IPA), 6benzylaminopurine and topolin conjugates (Górka et al, 2015;Pan et al, 2019) (Table 2). Cytokinins-like plant biostimulant activity was initially reported in the early 1970s in macroalgae extracts (Williams et al, 1981).…”

Plant Growth Biostimulants, Dietary Feed Supplements and Cosmetics Formulated with Supercritical CO2 Algal Extracts

“…The main chemical components of seaweed that affect plant growth are phytohormones (cytokinins, auxins and auxin-like compounds, indole acetic acid, abscisic acid), betaines, sterols, polysaccharides, minerals and trace elements, amino acids, polyphenols (e.g., phlorotannins) [ 16 , 18 , 19 , 29 , 74 , 75 ]. Plant hormones seem to be the most essential for enhancing the growth and development of crop plants [ 19 , 20 , 75 ]. Algal extracts stimulate not only plant growth, but also plant mass, the content of chlorophyll, carotenoids and improve root development [ 16 , 77 ].…”

“…The main scientific interest is in carotenoids (319), which can be divided into xanthophylls (astaxanthin (106), xanthophyll (89), fucoxanthin (61)) and carotenes (150) [ 2 , 15 ]. Recently, algae have been also considered as a source of plant hormones (31) [ 16 , 17 , 18 , 19 , 20 , 21 ].…”