Centro de Investigación Forestal de Lourizán - Unidad Asociada MBG-CSIC, Apdo 127, E-36080 Pontevedra, Galicia, Spain.
J Exp Bot. 2010 Oct;61(15):4437-47. doi: 10.1093/jxb/erq246.
Oleoresin produced and stored in pine tree leaves provides direct resistance to herbivores, while leaf volatile terpenes (LVT) in the resin are also powerful airborne infochemicals. Resin concentration and profile show considerable spatial and temporal phenotypic variation within and among pine populations. LVT biochemistry is known to be under genetic control, and although LVT should be plastic to diverse abiotic and biotic environmental factors such as nutrient availability and herbivore attack, little is known about their relative contributions and interactive effects. The aim of this paper was to clarify whether reduced phosphorus availability could increase the LVT concentration and affect the expression of herbivore-derived induced defences, and how plasticity would contribute to the phenotypic variation of LVT. The constitutive and methyl-jasmonate (MeJa) induced LVT concentration and profile were analysed in 17 half-sib Pinus pinaster families growing under two levels of P-availability (complete and P-limited fertilization). Individual terpene concentrations showed large additive genetic variation, which was more pronounced in the control than in MeJa-induced pines. MeJa application did not affect the LVT concentration, but significantly modified the LVT profile by depleting the α-pinene content and reducing the sesquiterpene fraction. Low P-availability strongly reduced plant growth and foliar nutrient concentrations, but did not affect LVT concentration and profile, and did not interact with MeJa-induction. Results indicate a strong homeostasis of LVT concentration to P-availability, and minor changes in the LVT profile due to MeJa-induction. Genetic variation appears to be the main source of phenotypic variation affecting the LVT concentration in this pine species.
松树叶中产生和储存的油树脂为植物提供了直接抵御食草动物的能力，而树脂中的叶挥发萜烯（LVT）也是强大的空气传播信息素。树脂的浓度和组成在松属种群内和种群间表现出相当大的空间和时间表型变异。LVT 生物化学受遗传控制，尽管 LVT 应该对各种非生物和生物环境因素（如养分供应和食草动物攻击）具有可塑性，但人们对它们的相对贡献和相互作用知之甚少。本文旨在阐明磷供应减少是否会增加 LVT 浓度并影响食草动物衍生诱导防御的表达，以及可塑性将如何为 LVT 的表型变异做出贡献。在两种磷供应水平（完全供应和磷限制施肥）下，对 17 个半同胞 Pinus pinaster 家系的组成型和茉莉酸甲酯（MeJa）诱导的 LVT 浓度和组成进行了分析。个体萜烯浓度表现出较大的加性遗传变异，在对照植株中比 MeJa 诱导的植株更为明显。MeJa 处理并未影响 LVT 浓度，但通过耗尽 α-蒎烯含量并降低半萜烯分数显著改变了 LVT 组成。低磷供应强烈抑制了植物生长和叶片养分浓度，但对 LVT 浓度和组成没有影响，也没有与 MeJa 诱导相互作用。结果表明，LVT 浓度对磷供应具有很强的内稳态，而 MeJa 诱导对 LVT 组成的变化较小。遗传变异似乎是影响该松树物种 LVT 浓度的表型变异的主要来源。
