Arnold Tom, Appel Heidi, Patel Vishal, Stocum Eileen, Kavalier Adam, Schultz Jack
Department of Biology, Dickinson College, Carlisle, PA 17013, USA.
Pesticide Research Laboratory, Department of Entomology, Penn State University, State College PA 19958, USA.
New Phytol. 2004 Oct;164(1):157-164. doi: 10.1111/j.1469-8137.2004.01157.x.
• Here, we examine the influence of source-to-sink carbohydrate (CHO) flow on the development of constitutive and inducible levels of phenylpropenoids in hybrid poplar (Populus nigra × P. deltoides) foliage to determine if secondary metabolic processes in plant modules can be inhibited in a predictable manner by events such as herbivory and the development of new leaves and reproductive structures, which alter the path of phloem-borne resources. • Phenylpropenoid concentrations were determined for developing foliage after CHO flow, measured as the translocation of C from labeled sources was manipulated. • Phenylpropenoid metabolism in both unwounded and induced sink leaves was directly and positively linked to rates of CHO import. Alterations in rates of translocation yielded different results, depending on how CHO import was affected: the removal of competing sinks rapidly and dramatically increased leaf phenolic contents, whereas phenolic levels (and their inducibility) tended to be reduced when import was interrupted. • High and inducible sink strength in developing poplar leaves provides resources for phenolic biosynthesis and, as a result, restrictions or re-directions of CHOs affect the foliar quality. Sink strength and the vascular architecture of plants, which confer upon them a modular nature, can determine the direction and magnitude of defense responses in trees.
• 在此，我们研究了源库间碳水化合物（CHO）流动对杂交杨树（黑杨× 三角叶杨）叶片中苯丙素类化合物组成型和诱导型水平发育的影响，以确定植物模块中的次生代谢过程是否会受到诸如食草作用以及新叶和生殖结构发育等事件的可预测性抑制，这些事件会改变韧皮部运输资源的路径。• 在控制从标记源转运¹⁴C作为CHO流动测量值后，测定发育中叶片的苯丙素类化合物浓度。• 未受伤和诱导型库叶中的苯丙素类化合物代谢与CHO输入速率直接呈正相关。转运速率的改变产生了不同结果，这取决于CHO输入如何受到影响：去除竞争库会迅速且显著增加叶片酚类含量，而当输入中断时酚类水平（及其诱导性）往往会降低。• 发育中杨树叶片中高且可诱导的库强度为酚类生物合成提供资源，因此，CHO的限制或重新定向会影响叶片质量。赋予植物模块化性质的库强度和维管结构可以决定树木防御反应的方向和程度。
