Progress in phenological modelling on the basis of metabolomic approaches

物候阶段的建模，如果树的开花，是基于几十年的温度总和，描述了木本植物在开花开始之前的冷却和强迫要求。这些方法可以追溯到Reaumur(1735)，他最初提出了“生长度日”的概念。近年来，越来越多的观点要求在物候模拟方面寻找新的方法，并对木本植物的休眠进行更深入的研究。如果我们考虑到物候模式的广泛应用，甚至会影响气候模式的结果，这一要求就很容易理解。直到今天，在物候模型中，仍然有许多参数必须根据观察进行优化，尽管已经考虑了植物的冷胁迫需求的一些基本生理知识（半机械方法）。对于这些模型的根本改进，限制是缺乏对木本植物休眠过程的了解，这一过程不能直接观察到，而且在文献中也没有充分描述。现代代谢组学方法为这一问题提供了解决方案，并允许对当前使用的物候模型进行精确验证，以及开发新的机制方法。因此，有必要以高时间分辨率跟踪选定的植物激素（脱落酸）及其前体（类胡萝卜素）的浓度变化，以便通过分析结果取代目前优化的休眠释放和个体发育开始的日期。此外，还将推导出游离氨基酸与花蕾休眠的关系以及花蕾随后的生长发育过程。对于新的物候建模方法，这些代谢物（浓度、时间过程）的变化必须与环境参数（天气、白天长度等）的可变性相关联。这必然需要有关物质对控制环境参数依赖性的多年高分辨率数据。这些研究现在是可行的，但科学上还没有实施。这一方法的可行性已在一项为期两年的甜樱桃试点研究中得到验证，并应在计划的项目中继续和加强。所建议的方法不仅限于果树的开花，它也可以应用于自然植被的树种，其中物候模拟存在更大的缺陷。

Modelling of phenological stages, such as the flowering of fruit trees, is based on temperature sums for many decades, describing both the chilling and the forcing requirements of woody plants until the beginning of flowering. These approaches go back to Reaumur (1735), who originally proposed the concept of Growing Degree Days. Recently, there is a growing body of opinion that asks for new methods in phenological modelling and more in-depth studies on the dormancy of woody plants. This requirement is easily understandable if we consider the wide application of phenological models, which even can affect the results of climate models.To this day in phenological models, still a number of parameters must be optimized on observations, although some basic physiological knowledge of the chilling and forcing requirement of plants is already considered (semi-mechanistic approaches). Limiting, for a fundamental improvement of these models, is the lack of knowledge about the course of dormancy in woody plants, which cannot be directly observed and which is also insufficiently described in the literature. Modern metabolomic methods provide a solution for this problem and allow both the exact validation of currently used phenological models as well as the development of new mechanistic approaches. For this reason it is necessary to track changes in the concentration of selected phytohormones (abscisic acid) and their precursors (carotenoids) in high temporal resolution, in order to replace the currently optimized dates for the release of dormancy and the beginning of ontogenetic development by analytical results. Furthermore, the context of free amino acids with dormancy and the subsequent growth and development processes of flower buds will be derived. For new phenological modelling approaches changes of these metabolites (concentration, temporal course) must be set in relation to the variability of environmental parameters (weather, day length, etc.). This necessarily requires multi-year and high-resolution data of the dependency of the relevant substances on controlling environmental parameters. These studies are now feasible, but scientifically not implemented, yet. The feasibility of this approach has already been tested in a 2-year pilot-study on sweet cherries and should be continued and intensified in the planned project. The suggested methodology is not only limited to the flowering of fruit trees, it can also be applied to tree species of the natural vegetation, where even greater deficits in phenological modelling exist.