Fluorescence procedures to assess the photosynthetic resilience in Scots pines after a surface fire

I G Gette,N V Pakharkova

doi:10.1088/1755-1315/421/6/062022

Abstract

Forest fire represents one of the most serious abiotic stress factors that influence the function and productivity of ecosystems globally. Siberian pine forests are often exposed to forest fires but they are not always harmful to them. We have analyzed the effects of repeated heat stress on the photosynthetic apparatus of Scotch pines before and after surface fire exposure that occurred in the growing season in 2014. The survey area was the forest steppe zone of Krasnoyarsk region (South Siberia). First, we investigated the changes in the temperature-dependent responses of photosynthesis in the needles by means of fast and delayed chlorophyll fluorescence. Our results are indicative of some acclimation of Scotch pines after fire to the repeated high temperature stress. Also, this paper discusses the possibility of using chlorophyll fluorescence parameters for evaluating the presence of physiological changes after the fire affects. The time after fire effect and growth season were found to be important to assess the repair of photosynthesis and pigment content.

Highlights

Siberian forests play a major role in the global climate system, they are crucial for terrestrial biodiversity, and they are a supply of major natural resources
We investigated the parameter of delayed fluorescence (DF) that demonstrates photosynthetic pine needle activity for the evaluation of pine needles resistance to high temperature stress, from trees within burned vs. unburned plots
We indicated DF on a fluorimeter “Foton – 10” that was produced at the Department of Ecology and Natural Resource Management at Siberian Federal University [6]

Summary

Introduction

Siberian forests play a major role in the global climate system, they are crucial for terrestrial biodiversity, and they are a supply of major natural resources. Sixty percent of forest fires occur in pine forests [2]. As a stress factor, may induce metabolic changes in trees. Heat stress due to fire effects is exerting strong effects on plant physiology and the resultant forest dynamics. During forest fires, the temperature gradient in the crown layer is very steep and heat events can have a major impact on photosynthetic features of plants. Trees are long-living organisms, and forest ecosystems need to adapt to changing environmental conditions in particular to high temperatures at fires. Different procedures such as chlorophyll fluorescence records are applied for exploring the processes involved in plant’s ability to survive and recover after an extreme stress [3]. Physiological and metabolic processes change at temperatures higher than the optimum [4]

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