Davis Micheal A, Boyd Robert S
1 School of Forestry, Auburn University, 411 S. Donahue Dr. Auburn, AL 36832, USA.
New Phytol. 2000 May;146(2):211-217. doi: 10.1046/j.1469-8137.2000.00632.x.
Plants use chemical defences to reduce damage from herbivores and the effectiveness of these defences can be altered by biotic and abiotic factors, such as herbivory and soil resource availability. Streptanthus polygaloides, a nickel (Ni) hyperaccumulator, possesses both Ni-based defences and organic defences (glucosinolates), but the extent to which these defences interact and respond to environmental conditions is unknown. S. polygaloides plants were grown on high-Ni and low-Ni soil and concentrations of Ni and glucosinolates were compared with those of the congeneric non-hyperaccumulator, S. insignus spp. insignus, grown under the same conditions. Ni contents were highest (4000 μg g dry tissue) in S. polygaloides plants grown on high-Ni soil. Glucosinolate content was significantly higher in S. insignus than in S. polygaloides suggesting that plants defended by Ni produce a lower concentration of organic defences. In a separate experiment, high-Ni S. polygaloides plants were exposed to simulated herbivory or live folivores to determine the inducibility of Ni-based and organic defences. Contents of Ni were not affected by either herbivory treatment, whereas glucosinolate concentrations were >30% higher in damaged plants. We concluded that the Ni-based defence of S. polygaloides is not induced by herbivory.
植物利用化学防御来减少食草动物造成的损害，这些防御的有效性会受到生物和非生物因素的影响，如食草作用和土壤资源可用性。多聚半枝莲（Streptanthus polygaloides）是一种镍（Ni）超积累植物，具有基于镍的防御和有机防御（硫代葡萄糖苷），但这些防御之间的相互作用程度以及对环境条件的响应尚不清楚。将多聚半枝莲植株种植在高镍和低镍土壤上，并将镍和硫代葡萄糖苷的浓度与在相同条件下生长的同属非超积累植物——微小半枝莲（Streptanthus insignus spp. insignus）进行比较。在高镍土壤上生长的多聚半枝莲植株中镍含量最高（4000微克/克干组织）。微小半枝莲中的硫代葡萄糖苷含量显著高于多聚半枝莲，这表明由镍防御的植物产生的有机防御浓度较低。在另一个实验中，将高镍的多聚半枝莲植株暴露于模拟食草作用或活体食叶动物下，以确定基于镍的防御和有机防御的诱导性。镍含量不受任何一种食草处理的影响，而受损植株中的硫代葡萄糖苷浓度则高出30%以上。我们得出结论，多聚半枝莲基于镍的防御不会因食草作用而被诱导。
