Collaborative Research: Developing Methods to Study Age-Related Changes in the Physiology of Forest Trees

合作研究：开发研究林木生理年龄相关变化的方法

• 批准号: 0110142
• 负责人: Barbara Bond
• 金额: $ 8.99万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0110142&HistoricalAwards=false
• 关键词: Collaborative; Research; Developing; Methods; Study

0110021 Michael Greenwood, University of Maine0110142 Barbara Bond, Oregon State University Trees continue to increase in size and complexity over life spans that may last many centuries, and each year the growing regions of their shoots produce new foliage and reproductive structures. As they grow older and larger, forest trees appear to grow more slowly, produce thicker foliage and more reproductive structures. These changes are likely to be associated with age-related declines in the growth rates of forest stands, which occur before the mid-point of the lifespan of important timber species. Although similar patterns of age- and size-related change in the morphology and physiology of foliage have been described for numerous species, the mechanisms governing these changes are virtually unknown. Possible explanations for these phenomena range from decreased photosynthesis due to increased resistance of water flow to a genetically controlled ageing process that slows growth and photosynthesis. Processes regulating maturation, ageing and senescence are fundamental to biology, and some of these processes are probably unique to large, long-lived trees. A more complete understanding of the basis for this decline is necessary to model and accurately predict the growth of forests over time.Reciprocal grafting of shoots between trees of different ages offers great potential as a tool to distinguish among explanations for changes in growth behavior. In this approach, shoots from old growth trees are grafted onto juvenile and young-mature trees, and shoots from juvenile and young-mature trees are grafted into the crowns of old-growth trees. The extent, direction and time-course of changes in the growth, morphology, and physiology of foliage produced by the grafted shoots will provide insight into the mechanisms governing age-related change. This study will attempt reciprocal grafting on two species of long-lived trees, red spruce and Douglas fir. These species are adapted to substantially different climatic regimes, so a comparative study will provide insights into the universality or variability of processes associated with age-related changes in tree growth.

0110021俄勒冈州立大学芭芭拉邦德分校迈克尔·格林伍德，在可能持续许多世纪的生命周期中，树木的大小和复杂性不断增加，每年它们的嫩枝生长区域都会产生新的叶子和生殖结构。随着年龄的增长和体型的增大，林木的生长速度似乎变慢了，树叶更厚了，生殖结构也更多了。这些变化可能与林木生长速度随年龄有关的下降有关，这种下降发生在重要木材树种的寿命中点之前。尽管在许多物种中已经描述了与年龄和大小有关的叶的形态和生理变化的相似模式，但支配这些变化的机制实际上是未知的。对这些现象的可能解释包括：由于水流阻力增加而导致的光合作用下降，以及基因控制的减慢生长和光合作用的衰老过程。调节成熟、衰老和衰老的过程是生物学的基础，其中一些过程可能是大型长寿树所独有的。对这种下降的基础有更全面的了解，这对于模拟和准确预测森林随时间的生长是必要的。不同树龄的树木之间的相互嫁接提供了巨大的潜力，作为区分生长行为变化的解释的工具。在这种方法中，老树的枝条嫁接到幼树和幼树上，幼树和幼树的枝条嫁接到老树的树冠上。嫁接枝条产生的叶片的生长、形态和生理变化的程度、方向和时间进程将有助于深入了解与年龄相关的变化机制。这项研究将尝试在两种长寿树种--红云杉和道格拉斯冷杉上进行相互嫁接。这些物种适应了非常不同的气候制度，因此，比较研究将提供对与年龄相关的树木生长变化相关过程的普遍性或变异性的洞察。