Responses of Autumn Phenology to Climate Change and the Correlations of Plant Hormone Regulation

Shixi Zhang,Quansheng Ge,Junhu Dai

doi:10.1038/s41598-020-65704-8

Shixi Zhang, Quansheng Ge + Show 1 more

Open Access

https://doi.org/10.1038/s41598-020-65704-8

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Abstract

Current understanding of autumn phenological responses to climate change in deciduous tree species remains limited, mainly due to the difficulties in defining autumn events and the lack of knowledge about its mechanism. Here we applied a method based on measuring chlorophyll A (Chla) content in leaf tissue during the entire autumn senescence processes to appropriately quantify autumn phenological processes. Beginning of leaf coloring could be defined as when about 50% of the Chl was lost. End of leaf coloring could be defined as when about 95% of the Chl was lost. Then the mechanism behind the timing of autumn senescence responses to climate change through hormone regulation was studied for the first time. Four dominate deciduous tree species with representative senescence type (Salix babylonica, Ginkgo biloba, Acer mono, Cotinus coggygria) were chosen as the subject of study. Variations in climate factors (temperature, day length, precipitation, humidity) were recorded and nine major endogenous hormones (IAA, IPA, ZR, DHZR, GA3, GA4, ABA, MeJA, BR) in leaf tissues were monitored during the entire autumn senescence processes. The experimental results verified temperature and day length are the major climate factors affecting autumn phenology. Low temperature and short day length could result in the decrease of ZR level and the increase of ABA level in leaf tissue, which directly trigger/promote senescence. Meanwhile, low temperature and short day length could cause the decrease of MeJA level and the increase of GA3 and GA4 level, which regulate the timing of autumn senescence indirectly through ZR, ABA, and IAA. Our study improves the understanding of autumn phenological response to climate change in deciduous trees.

Highlights

Climate change has caused dramatic plant phenological shifts with substantial ecological and environmental consequences[1]
In that formula, chlorophyll A (Chla) is significantly correlated with abscisic acid (ABA), zeatin riboside (ZR), and indole-3-acetic acid (IAA)
Low temperature and short day length could result in the decrease of ZR level and the increase of ABA level, which directly trigger/promote senescence

Summary

Introduction

Climate change has caused dramatic plant phenological shifts with substantial ecological and environmental consequences[1]. Current understanding of the environmental control of autumn senescence mainly comes from endogenous hormones, which play important roles in regulating developmental processes involved in plant responses to changes in climate[10]. The understanding of hormones in controlling senescence and responses to climate change has mostly based on behavior of Arabidopsis, a favorite model plant for biological study. The objective of this study is to provide a method that define autumn senescence appropriately as well as investigate the mechanism behind autumn phenological responses to climate change through hormone regulation for deciduous tree species. The content of chlorophyll in in leaf tissues during the entire autumn senescence processes were monitored to provide a standardized and comparable method on defining autumn phenological events. The mechanism of climate factors affecting the timing of autumn senescence through endogenous hormone was elucidated

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