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

Piotr Salachna

doi:10.3390/agronomy10020169

Abstract

New solutions allowing for the shortening of the growing cycle and improvements in plant quality are constantly sought in order to improve the efficiency of bedding plant production under covers. Biodegradable polysaccharides and their derivatives have become increasingly popular in horticulture as plant growth promoters. A greenhouse pot experiment was conducted to evaluate the effects of depolymerized gellan of different molecular weights (MW 56 kDa and 77 kDa) on the growth and physiological parameters of ornamental bedding plants Rudbeckia hirta L., Salvia splendens Sellow ex J.A. Schultes, Scabiosa atropurpurea L., and Tithonia rotundifolia (Mill.) S.F. Blake. The results showed that the application of depolymerized gellan accelerated flowering and stimulated the growth of all assessed species, regardless of MW. The plants treated with depolymerized gellan grew higher and had greater fresh weight of their above-ground parts, higher leaf relative chlorophyll content (SPAD; soil and plant analysis development), and higher stomatal conductance (gs). The use of 56 kDa gellan fraction resulted in the formation of inflorescences with the greatest fresh weight in S. atropurpurea. Leaves of R. hirta treated with this fraction showed the highest values of SPAD and gs. This study demonstrated that gellan derivatives of low MW may be used for the production of innovative plant biostimulants.

Highlights

Production of bedding plants, including annual, biennial, and perennial species, is one of the most important branches of the horticultural market
This study demonstrated that gellan derivatives of low molecular weight (MW) may be used for the production of innovative plant biostimulants
Plant growth and development may be positively affected by using natural biostimulants

Summary

Introduction

Production of bedding plants, including annual, biennial, and perennial species, is one of the most important branches of the horticultural market. The sector has enjoyed dynamic growth due to a high public demand for ornamental plants and the increasing use of bedding plants in urban green areas. The sustainable development of floriculture requires modern and environmentally friendly solutions that can maximize the display of plant potential [4,5]. To this end, growers increasingly often use biostimulants that help to intensify plant propagation, growth, and flowering and improve stress tolerance [6,7,8]. Studies on the use of natural biostimulants in the cultivation of ornamental plants are considerably fewer than in the case of vegetables, fruits, and other crops [9,10], and this gap should be urgently filled

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