Absorption, translocation and metabolism of L-DOPA in barnyardgrass and lettuce: their involvement in species-selective phytotoxic action
Absorption, translocation and metabolism of L-DOPA in barnyardgrass and lettuce: their involvement in species-selective phytotoxic action
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DOI：
10.1023/b:grow.0000045996.72922.1b
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发表时间：
2004-07-01
影响因子：
4.2
通讯作者：
Matsumoto, H
中科院分区：
文献类型：
--
作者：
Hachinohe, M;Sunohara, Y;Matsumoto, H
L-DOPA (L-3,4-Dihydroxyphenylalanine) is one of the most highly active allelochemicals. L-DOPA is exuded from the roots of velvetbean [Mucuna pruriens (L.) DC.变种utilis] into soil, and causes growth inhibition of other species. In order to highly clarify the phytotoxic mechanism Of L-DOPA, its effect on 32 species was surveyed, and absorption, translocation and metabolism in a tolerant species, barnyardgrass (Echinochloa crus-galli L.), and susceptible species, lettuce (Lactuca sativa L. cv. Great lakes 366), were examined at the germination stage. The species tested showed distinctly different responses to L-DOPA, with root elongation being more suppressed than that of shoots. Barnyardgrass was 77-fold more tolerant than lettuce based on the GR(50) values determined 5 days after treatment. Absorption Of L-DOPA in barnyardgrass and lettuce increased continuously during a 5 day exposure period, however,barnyardgrass absorbed a larger amount Of L-DOPA than lettuce. The translocation of radioactivity derived from C-14-L-DOPA to shoots was greater in lettuce than in barnyardgrass 3 and 5 days after treatment. Although the L-DOPA absorbed was metabolized in the roots of both species, the percentage of radioactive C-14-L-DOPA increased in lettuce continuously but decreased in barnyardgrass over 5 days. In lettuce roots, a continuous increase of L-DOPA but not other metabolites was observed. However, the concentration of L-DOPA was higher in barnyardgrass roots compared with lettuce roots throughout the exposure period. These results suggest that L-DOPA itself is the active form, and the species-selective phytotoxicity of L-DOPA is at least partly due to metabolism and not due to absorption or translocation.
L-DOPA (L-3,4-Dihydroxyphenylalanine) is one of the most highly active allelochemicals. L-DOPA is exuded from the roots of velvetbean [Mucuna pruriens (L.) DC. var. utilis] into soil, and causes growth inhibition of other species. In order to highly clarify the phytotoxic mechanism Of L-DOPA, its effect on 32 species was surveyed, and absorption, translocation and metabolism in a tolerant species, barnyardgrass (Echinochloa crus-galli L.), and susceptible species, lettuce (Lactuca sativa L. cv. Great lakes 366), were examined at the germination stage. The species tested showed distinctly different responses to L-DOPA, with root elongation being more suppressed than that of shoots. Barnyardgrass was 77-fold more tolerant than lettuce based on the GR(50) values determined 5 days after treatment. Absorption Of L-DOPA in barnyardgrass and lettuce increased continuously during a 5 day exposure period, however,barnyardgrass absorbed a larger amount Of L-DOPA than lettuce. The translocation of radioactivity derived from C-14-L-DOPA to shoots was greater in lettuce than in barnyardgrass 3 and 5 days after treatment. Although the L-DOPA absorbed was metabolized in the roots of both species, the percentage of radioactive C-14-L-DOPA increased in lettuce continuously but decreased in barnyardgrass over 5 days. In lettuce roots, a continuous increase of L-DOPA but not other metabolites was observed. However, the concentration of L-DOPA was higher in barnyardgrass roots compared with lettuce roots throughout the exposure period. These results suggest that L-DOPA itself is the active form, and the species-selective phytotoxicity of L-DOPA is at least partly due to metabolism and not due to absorption or translocation.