title: Root growth and enzymes related to the lignification of maize seedlings exposed to the allelochemical L-DOPA.
abstract: L-3,4-Dihydroxyphenylalanine (L-DOPA) is a known allelochemical exuded from the roots of velvet bean (Mucuna pruriens L. Fabaceae). In the current work, we analyzed the effects of L-DOPA on the growth, the activities of phenylalanine ammonia-lyase (PAL), tyrosine ammonia-lyase (TAL), and peroxidase (POD), and the contents of phenylalanine, tyrosine, and lignin in maize (Zea mays) roots. Three-day-old seedlings were cultivated in nutrient solution with or without 0.1 to 2.0 mM L-DOPA in a growth chamber (25°C, light/dark photoperiod of 12/12, and photon flux density of 280  μ mol m(-2) s(-1)) for 24 h. The results revealed that the growth (length and weight) of the roots, the PAL, TAL, and soluble and cell wall-bound POD activities decreased, while phenylalanine, tyrosine, and lignin contents increased after L-DOPA exposure. Together, these findings showed the susceptibility of maize to L-DOPA. In brief, these results suggest that the inhibition of PAL and TAL can accumulate phenylalanine and tyrosine, which contribute to enhanced lignin deposition in the cell wall followed by a reduction of maize root growth.
authors.affiliation: Laboratory of Plant Biochemistry, Department of Biochemistry, University of Maringá, Av. Colombo 5790, 87020-900 Maringá, PR, Brazil.
authors.forename: Rita
authors.initials: R
authors.lastname: de Cássia Siqueira-Soares
authors.affiliation: Laboratory of Plant Biochemistry, Department of Biochemistry, University of Maringá, Av. Colombo 5790, 87020-900 Maringá, PR, Brazil.
authors.forename: Anderson Ricardo
authors.initials: AR
authors.lastname: Soares
authors.affiliation: Laboratory of Plant Biochemistry, Department of Biochemistry, University of Maringá, Av. Colombo 5790, 87020-900 Maringá, PR, Brazil.
authors.forename: Angela Valderrama
authors.initials: AV
authors.lastname: Parizotto
authors.affiliation: Laboratory of Plant Biochemistry, Department of Biochemistry, University of Maringá, Av. Colombo 5790, 87020-900 Maringá, PR, Brazil.
authors.forename: Maria
authors.initials: M
authors.lastname: de Lourdes Lucio Ferrarese
authors.affiliation: Laboratory of Plant Biochemistry, Department of Biochemistry, University of Maringá, Av. Colombo 5790, 87020-900 Maringá, PR, Brazil.
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Ferrarese-Filho
mesh_terms: D007980:Levodopa / Q000737:chemistry / Q000494:pharmacology*; D008031:Lignin / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects* / Q000502:physiology*; D036226:Seedlings / Q000187:drug effects*; D003313:Zea mays / Q000187:drug effects* / Q000502:physiology*
chemical_list: D007980:Levodopa; D008031:Lignin