Collaborative Research: Does variation in development explain variation in phenological responses to temperature?

北方森林（覆盖美国和加拿大29%的栖息地）正在经历更早的春天，更温暖的夏天和更长的福尔斯。虽然许多植物通过提早开花来应对温暖的春天，但相当多的物种没有做出反应，有些甚至显示出延迟开花。这种模式与基于对温度的充分理解的生理反应的预测不一致。 然而，对于生长在北方森林中的植物来说，以花蕾爆裂为结束的过程实际上在花朵开放前一年或更长时间就开始了，这是一个被称为“预形成”的发育过程。这项研究将检验这一假设，即温度升高对预形成期延长的影响解释了延迟开花。 温度升高对预形成的影响可能会限制植物适应环境变化的程度。发现发育的强大作用可以大大提高我们预测高纬度社区开花时间的能力，也可以深入了解温带树木和灌木（其中大多数是预成形花）将如何应对温度升高。该项目还将包括公民科学家，他们将获得阿拉斯加各地的物候学、温度和积雪深度数据。该项目将评估温暖温度对花原基发育的三种潜在影响：1）温度升高可能诱导早期萌芽和休眠; 2）诱导更快的发育和/或延迟芽的形成，以便一些芽在萌发当年的秋天成熟;和3）延迟花的萌发。将研究8种林下的北方灌木;他们的身材小，使他们适合实验温度操纵，因为他们是木本的，他们可能会分享功能的preformation与优势的树木和灌木的不同植物群落。开顶的温室将用于提高一到两个生长季节的温度，并将在三年内进行开发。温度将涉及到潜在的发展决定因素的花开放：启动的时间，发展速度，停止增长。通过操纵和分析积雪融化时间，生长开始日期和温度对代表性物种花发育的整个多年轨迹的影响，研究人员将确定“非典型”物候反应的机制。

The boreal forest (a habitat that covers 29% of the US and Canada) is undergoing earlier springs, warmer summers, and extended falls. While many plants respond to warmer springs by flowering earlier, a significant number of species do not respond, and some even show delayed flowering. Such patterns are inconsistent with predictions based on well-understood physiological responses to temperature. For plants that grow in boreal forest, however, the process that ends in the bursting of flower buds actually begins a year or more before flowers open, a developmental process known as "preformation". This research will test the hypothesis that the effects of rising temperatures on the extended period of preformation explain delayed flowering. The effects of rising temperatures on preformation may limit the extent to which plants can adapt to environmental variability. The discovery of a strong role for development could dramatically improve our ability to predict the timing of flowering in high-latitude communities and may also provide insights into how temperate trees and shrubs, the majority of which preform flowers, will respond to increasing temperatures. This project will also involve citizen scientists, who will obtain phenology, temperature and snow depth data from across Alaska.This project will evaluate three potential effects of warm temperatures on the development of flower primordia: increasing temperatures could 1) induce early bud set and dormancy; 2) induce more rapid development and / or a delay in bud set so that some buds mature in the fall of the year in which they were initiated; and 3) delay flower initiation. Eight species of understory boreal shrubs will be studied; their small stature makes them amenable to experimental temperature manipulation, and because they are woody they likely share features of preformation with the dominant trees and shrubs of diverse plant communities. Open-topped chambers will be used to raise temperatures for one or two growing seasons, and development will be followed over the course of three years. Temperature will be related to potential developmental determinants of flower opening: timing of initiation, rate of development, and cessation of growth. By manipulating and analyzing the effects of time of snow melt, date of growth initiation and temperature across the entire multi-year trajectory of flower development for representative species, the researchers will identify the mechanisms that underlie "non-typical" phenological responses.