Soybean root growth inhibition and lignification induced by p-coumaric acid

作者：Lucca Zanardo Daniele Iara; Lima Rogerio Barbosa; Lucio Ferrarese Maria de Lourdes; Bubna Gisele Adriana; Ferrarese Filho Osvaldo

来源：Environmental and Experimental Botany, 2009, 66(1): 25-30.

DOI：10.1016/j.envexpbot.2008.12.014

• Allelopathy
• Lignin
• Lignin monomers
• Peroxidase
• Phenylalanine ammonia-lyase
• Phenylpropanoid pathway

The effects of 0.25-2 mM p-coumaric acid, a phenylpropanoid metabolite with recognized allelopathic properties, were tested on root growth, cell viability, phenylalanine ammonia-lyase (PAL) activities, soluble and cell wall-bound peroxidase (POD) activities, hydrogen peroxide (H(2)O(2).) level and lignin content and its monomeric composition in soybean (Glycine max (L.) Merr.) roots. At >= 0.25 mM, exogenously supplied p-coumaric acid induced premature cessation of root growth, increased POD activity and lignin content and decreased the H(2)O(2) content. At >= 0.5 mM, the allelochemical decreased the cell viability and PAL activity. When applied jointly with PIP (an inhibitor of the cinnamate 4-hydroxylase, C4H), 1 mM p-coumaric acid increased lignin content. In contrast, the application of MDCA (an inhibitor of the 4-coumarate:CoA ligase, 4CL) with p-coumaric acid did not increase lignin content. The lignin monomeric composition of p-coumaric acid-exposed roots revealed a significant increase of p-hydroxyphenyl (H) and guaiacyl (G) units. Taken together, these results suggest that p-coumaric acid's mode of action is entry via the phenylpropanoid pathway, resulting in an increase of H and G lignin monomers that solidify the cell wall and restrict soybean root growth.

• 出版日期2009-4