TY - JOUR
T1 - Phytotoxic substances with allelopathic activity may be central to the strong invasive potential of Brachiaria brizantha
AU - Kato-Noguchi, Hisashi
AU - Kobayashi, Ai
AU - Ohno, Osamu
AU - Kimura, Fukiko
AU - Fujii, Yoshiharu
AU - Suenaga, Kiyotake
PY - 2014/4/15
Y1 - 2014/4/15
N2 - The grass Brachiaria brizantha, native to eastern Africa, becomes naturalized and dominant quickly in the non-native areas. It was hypothesized that phytotoxic chemical interaction between this plant and native plants may play an important role in the invasion of B. brizantha. However, no potent phytotoxic substance has been reported in this species. Therefore, we investigated possible allelopathic activity and searched for phytotoxic substances with allelopathic activity in B. brizantha. An aqueous methanol extract of B. brizantha inhibited the growth of roots and shoots of garden cress (Lepidium sativum), lettuce (Lactuca sativa), timothy (Phleum pratense) and ryegrass (Lolium multiflorum) seedlings. The extract was purified by several chromatographic runs and three allelopathically active substances were isolated and identified by spectral analysis as (6R,. 9R)-3-oxo-α-ionol, (6R,. 9S)-3-oxo-α-ionol and 4-ketopinoresinol. (6R,. 9R)-3-Oxo-α-ionol and (6R,. 9S)-3-oxo-α-ionol inhibited root and shoot growth of garden cress at concentrations greater than 30 and 10. μM, respectively. The activity of (6R,. 9S)-3-oxo-α-ionol was 5.3- to 6.2-fold that of (6R,. 9R)-3-oxo-α-ionol. The stereochemistry of the hydroxyl group at position C-9 may be important for the inhibitory activities of those compounds. 4-Ketopinoresinol inhibited root and shoot growth of garden cress at concentrations greater than 30. μM. The growth inhibitory activity of (6R,. 9S)-3-oxo-α-ionol was the greatest and followed by 4-ketopinoresinol and (6R,. 9R)-3-oxo-α-ionol. These results suggest that those phytotoxic substances may contribute to the allelopathic effect caused by B. brizantha and may be involved in the invasion of B. brizantha.
AB - The grass Brachiaria brizantha, native to eastern Africa, becomes naturalized and dominant quickly in the non-native areas. It was hypothesized that phytotoxic chemical interaction between this plant and native plants may play an important role in the invasion of B. brizantha. However, no potent phytotoxic substance has been reported in this species. Therefore, we investigated possible allelopathic activity and searched for phytotoxic substances with allelopathic activity in B. brizantha. An aqueous methanol extract of B. brizantha inhibited the growth of roots and shoots of garden cress (Lepidium sativum), lettuce (Lactuca sativa), timothy (Phleum pratense) and ryegrass (Lolium multiflorum) seedlings. The extract was purified by several chromatographic runs and three allelopathically active substances were isolated and identified by spectral analysis as (6R,. 9R)-3-oxo-α-ionol, (6R,. 9S)-3-oxo-α-ionol and 4-ketopinoresinol. (6R,. 9R)-3-Oxo-α-ionol and (6R,. 9S)-3-oxo-α-ionol inhibited root and shoot growth of garden cress at concentrations greater than 30 and 10. μM, respectively. The activity of (6R,. 9S)-3-oxo-α-ionol was 5.3- to 6.2-fold that of (6R,. 9R)-3-oxo-α-ionol. The stereochemistry of the hydroxyl group at position C-9 may be important for the inhibitory activities of those compounds. 4-Ketopinoresinol inhibited root and shoot growth of garden cress at concentrations greater than 30. μM. The growth inhibitory activity of (6R,. 9S)-3-oxo-α-ionol was the greatest and followed by 4-ketopinoresinol and (6R,. 9R)-3-oxo-α-ionol. These results suggest that those phytotoxic substances may contribute to the allelopathic effect caused by B. brizantha and may be involved in the invasion of B. brizantha.
KW - Allelopathy
KW - Brachiaria brizantha
KW - Growth inhibitor
KW - Invasive plant
KW - Phytotoxin
UR - http://www.scopus.com/inward/record.url?scp=84896307921&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84896307921&partnerID=8YFLogxK
U2 - 10.1016/j.jplph.2013.11.010
DO - 10.1016/j.jplph.2013.11.010
M3 - Article
C2 - 24655388
AN - SCOPUS:84896307921
VL - 171
SP - 525
EP - 530
JO - Z. PFLANZENPHYSIOL.
JF - Z. PFLANZENPHYSIOL.
SN - 0176-1617
IS - 7
ER -