Mass Spectrometry & Spectroscopy


Leaf Polyphenols as Indicators of Climatic Adaptation of Beech (Fagus sylvatica L.) – an HPLC-MS/MS via MRM Approach


Tamás Hofmann, Esztella Tálos-Nebehaj and Levente Albert, University of Sopron, Institute of Chemistry, Bajcsy-Zsilinszky str. 4., Sopron, 9400, Hungary Email: hofmann.tamas@uni-sopron.hu, Tel: +36 99 518 311


Figure 1. Modelled present-day (averaged for 1961–90) and future (averaged f 2100) potential natural vegetation (PNV) in Europe [1].


Temperate zone forests are heavily affected by climate change. Certain species like beech (Fagus sylvatica L.), common across Europe with high economic and ecological value are especially vulnerable and threatened by a retreat or possible extinction. A future task for forestry is to fi nd varieties which can adapt to changing climate due to their effi cient chemical defence mechanisms. Antioxidant leaf polyphenols represent one of these defence mechanisms. This work studied the relative quantitative evaluation of 44 compounds by HPLC-MS/MS via MRM peak areas as well as the determination of the antioxidant capacities from leaves of different beech varieties. Correlation analysis between parameters revealed that some of the most effi cient antioxidant polyphenols ((+)-Catechin, Procyanidin C trimer 3, Procyanidin B dimer 4) were found in the highest levels in the leaves of the most vulnerable varieties, with the poorest growing results and also with the highest antioxidant capacities. Results showed the novel potentials of HPLC-MS/MS in the research of biomarkers of climatic adaptation in forest trees.


Introduction


One of the apparent results of climate change is the retreat of native forests all over the world which can also result the extinction of tree species vulnerable to changed climatic conditions [1,2]. The effects of these changes on forest ecosystems, the economy as well as society are diffi cult to predict. European beech (Fagus sylvatica L.), which is one of the most common broad-leaved tree species in Europe and has a signifi cant ecological and economic importance. It is especially vulnerable to increasing temperature and lower precipitation. According to recent estimations the area covered by beech forests will decrease dramatically in the next decades due to the change of climatic conditions [1,3]. Hungarian beech stands will be affected especially by these changes [4-7] which will cause beech to retreat to cooler and more humid habitats which will have unpredictable effects on forest ecosystems (Figure 1).


The International Union of Forest Research Organizations (IUFRO) started an in the 1990s in order to forecast future changes of beech forests in Europe: exp forests were planted at several locations to study the growth behaviour and ad different beech varieties (originating from different parts of Europe) at a given lo under the given climatic conditions. In other words, to find out which are the va originate from a different geographic location, but are able to adapt to the clima investigated location. These varieties could then provide propagating material f afforestationʼs at these locations. In the framework of the IUFRO project, an ex forest was also planted in Hungary at Bucsuta (Zala county) in 1998. Small sta beech varieties, originating from different parts of Europe have been raised the 19 years (Figure 2).


Figure 2. Origin of the beech varieties grown at Bucsuta (H) in the framework of the IUFRO project.


The main question of the present article is, if there are such chemical compounds which are in a direct quantitative relationship with the degree of climatic adaptation of beech varieties, by showing a signifi cant correlation with growth parameters (e.g. average trunk diameter). By identifi cation and use of such chemical indicators those varieties and individuals of beech could be selected that will provide propagating material for the future afforestation and promote the preservation of beech forests in their native habitat.


Figure 1. Modelled present-day (averaged for 1961–90) and future (averaged for 2071–2100) potential natural vegetation (PNV) in Europe [1].


Figure 1. Modelled present-day (averaged for 1961–90) and future (averaged for 2071– 2100) potential natural vegetation (PNV) in Europe [1].


The International Union of Forest Research Organizations (IUFRO) started an experiment in the 1990s in order to forecast future changes of beech forests in Europe: experimental forests were planted at several locations to study the growth behaviour and adaptability of different beech varieties (originating from different parts of Europe) at a given location under the given climatic conditions. In other words, to fi nd out which are the varieties that originate from a different geographic location, but are able to adapt to the climate at the investigated location. These varieties could then provide propagating material for future afforestation’s at these locations. In the framework of the IUFRO project, an experimental forest was also planted in Hungary at Bucsuta (Zala county) in 1998. Small stands of 36 beech varieties, originating from different parts of Europe have been raised there for over 19 years (Figure 2).


One of the major defence pathways of plants is the antioxidant system. Antioxidants can be either enzymatic or non-enzymatic. Polyphenols represent one of the most important types of non-enzymatic antioxidants. The most comprehensive investigation on beech leaf polyphenols was done by Cadahia et al. [8] who have identifi ed and characterised 43 compounds structurally by the HPLC-MS/MS technique, concluding that these compounds could be used for future studies on physiological and molecular mechanisms involved in biotic or abiotic stress in beech trees.


The International Union of Forest Research Organizations (IUFRO) started an experiment in the 1990s in order to forecast future changes of beech forests in Europe: experimental forests were planted at several locations to study the growth behaviour and adaptability of different beech varieties (originating from different parts of Europe) at a given location under the given climatic conditions. In other words, to find out which are the varieties that originate from a different geographic location, but are able to adapt to the climate at the investigated location. These varieties could then provide propagating material for future afforestationʼs at these locations. In the framework of the IUFRO project, an experimental forest was also planted in Hungary at Bucsuta (Zala county) in 1998. Small stands of 36 beech varieties, originating from different parts of Europe have been raised there for over 19 years (Figure 2).


The present research reports on the quantitative analysis of beech leaf polyphenols in 6 selected beech varieties, grown at Bucsuta (H) using HPLC-MS/MS technique and Multiple Reaction Monitoring (MRM). Correlation analyses were conducted to reveal relationships between concentrations of individual compounds and ABTS (2,2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) antioxidant capacity, growth parameters as well as Ellenberg’s climatic index. By the evaluation and interpretation of relationships the most effi cient antioxidant compounds were identifi ed which could be the markers of the degree of climatic adaptation of beech. Results could contribute to selecting ‘resistant’ beech varieties that are suitable for future afforestation’s in Hungary in order to maintain native beech vegetation.


INTERNATIONAL LABMATE - APRIL 2017


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