Oligo-Alginate with Low Molecular Mass Improves Growth and Physiological Activity of Eucomis autumnalis under Salinity Stress

Abstract

Biopolymers have become increasingly popular as biostimulators of plant growth. One of them, oligo-alginate, is a molecule that regulates plant biological processes and may be used in horticultural practice as a plant growth regulator. Biostimulators are mainly used to improve plant tolerance to abiotic stresses, including salinity. The aim of the study was to assess the effects of salinity and oligo-alginate of various molecular masses on the growth and physiological activity of Eucomis autumnalis. The species is an ornamental and medicinal plant that has been used for a long time in the traditional medicine of South Africa. The bulbs of E. autumnalis were coated using depolymerized sodium alginate of molecular mass 32,000; 42,000, and 64,000 g mol−1. All of these oligo-alginates fractions stimulated plant growth, and the effect was the strongest for the fraction of 32,000 g mol−1. This fraction was then selected for the second stage of the study, when plants were exposed to salt stress evoked by the presence of 100 mM NaCl. We found that the oligo-alginate coating mitigated the negative effects of salinity. Plants treated with the oligomer and watered with NaCl showed smaller reduction in the weight of the above-ground parts and bulbs, pigment content and antioxidant activity as compared with those not treated with the oligo-alginate. The study demonstrated for the first time that low molecular mass oligo-alginate may be used as plant biostimulator that limits negative effects of salinity in E. autumnalis.

Ascophyllum nodosum Extract Biostimulant Processing and Its Impact on Enhancing Heat Stress Tolerance During Tomato Fruit Set

“…The most significant differences between PSI-494 and C129 were a smaller main carbohydrate peak and the higher relative abundance of secondary peaks. Previous studies have confirmed that low M w polysaccharides and oligosaccharides from seaweeds were able to stimulate efficiently abiotic stress tolerance in several crop species (Liu et al, 2013;Wu et al, 2016;Singh et al, 2017;Li et al, 2018;Salachna et al, 2018). Our results would also suggest that there is a link between the lower molecular size of carbohydrates inside ANEs and enhanced heat stress tolerance in tomato plants at reproductive stage.…”

Effects of Depolymerized Gellan with Different Molecular Weights on the Growth of Four Bedding Plant Species

“…However, significant differences were found for inflorescence fresh weight in S. atropurpurea and for physiological parameters in R. hirta, indicating a stronger stimulating effect of the depolymerized gellan of lower M W of 56 kDa. Other studies [21,40] also reported intensified biomass production and photosynthesis following treatment with low M W polysaccharide derivatives. Stronger biological activity of low M W biopolymers may be due to their faster and easier penetration into plant tissues and cells, where they bind with cell membrane receptors and initiate metabolic changes [16,18,21].…”

Purification and Characterization of a Novel Endolytic Alginate Lyase from Microbulbifer sp. SH-1 and Its Agricultural Application

“…AOS as the degradation product of alginate, especially enzymatic hydrolysis products of alginate, is a potent plant elicitor [16]. Previous studies have reported that alginate oligosaccharides are effective in stimulating seed germination [48], promoting root growth [16], enhancing plant tolerance to drought and salt stress [18,49], and alleviating toxic effects of Cd [50]. However, the elicitor-active effect of degradation products against chilling has not been thoroughly elucidated.…”