Department of Botany, Panjab University, Chandigarh, 160014, India.
Protoplasma. 2013 Jun;250(3):691-700. doi: 10.1007/s00709-012-0446-y. Epub 2012 Aug 31.
β-Pinene, an oxygenated monoterpene, is abundantly found in the environment and widely occurring in plants as a constituent of essential oils. We investigated the phytotoxicity of β-pinene against two grassy (Phalaris minor, Echinochloa crus-galli) and one broad-leaved (Cassia occidentalis) weeds in terms of germination and root and shoot growth. β-Pinene (0.02-0.80 mg/ml) inhibited the germination, root length, and shoot length of test weeds in a dose-response manner. The inhibitory effect of β-pinene was greater in grassy weeds and on root growth than on shoot growth. β-Pinene (0.04-0.80 mg/ml) reduced the root length in P. minor, E. crus-galli, and C. occidentalis over that in the control by 58-60, 44-92, and 26-85 %, respectively. In contrast, shoot length was reduced over the control by 45-97 % in P. minor, 48-78 % in E. crus-galli, and 11-75 % in C. occidentalis at similar concentrations. Further, we examined the impact of β-pinene on membrane integrity in P. minor as one of the possible mechanisms of action. Membrane integrity was evaluated in terms of lipid peroxidation, conjugated diene content, electrolyte leakage, and the activity of lipoxygenases (LOX). β-Pinene (≥0.04 mg/ml) enhanced electrolyte leakage by 23-80 %, malondialdehyde content by 15-67 %, hydrogen peroxide content by 9-39 %, and lipoxygenases activity by 38-383 % over that in the control. It indicated membrane peroxidation and loss of membrane integrity that could be the primary target of β-pinene. Even the enhanced (9-62 %) activity of protecting enzymes, peroxidases (POX), was not able to protect the membranes from β-pinene (0.04-0.20 mg/ml)-induced toxicity. In conclusion, our results show that β-pinene inhibits root growth of the tested weed species through disruption of membrane integrity as indicated by enhanced peroxidation, electrolyte leakage, and LOX activity despite the upregulation of POX activity.
β-蒎烯是一种含氧单萜，在环境中大量存在，广泛存在于植物精油中。我们研究了β-蒎烯对两种草本杂草（Phalaris minor，Echinochloa crus-galli）和一种阔叶杂草（Cassia occidentalis）的发芽和根、茎生长的植物毒性。β-蒎烯（0.02-0.80mg/ml）以剂量反应方式抑制测试杂草的发芽、根长和茎长。β-蒎烯对草本杂草和根生长的抑制作用大于对茎生长的抑制作用。β-蒎烯（0.04-0.80mg/ml）使 P.minor、E.crus-galli 和 C.occidentalis 的根长比对照分别减少 58-60%、44-92%和 26-85%。相比之下，在类似浓度下，P.minor 的茎长比对照减少 45-97%，E.crus-galli 的茎长减少 48-78%，C.occidentalis 的茎长减少 11-75%。此外，我们研究了β-蒎烯对 P.minor 膜完整性的影响，作为其作用机制之一。通过脂质过氧化、共轭二烯含量、电解质泄漏和脂氧合酶（LOX）活性来评估膜完整性。β-蒎烯（≥0.04mg/ml）使电解质泄漏增加 23-80%，丙二醛含量增加 15-67%，过氧化氢含量增加 9-39%，脂氧合酶活性增加 38-383%，与对照相比。这表明膜过氧化和膜完整性的丧失可能是β-蒎烯的主要靶标。即使是保护酶过氧化物酶（POX）的活性增强（9-62%）也不能使膜免受β-蒎烯（0.04-0.20mg/ml）诱导的毒性。总之，我们的结果表明，β-蒎烯通过破坏膜完整性抑制测试杂草物种的根生长，这表明过氧化、电解质泄漏和 LOX 活性增强，尽管 POX 活性上调。
