Implications of High Temperature and Elevated CO2 on Flowering Time in Plants.

S V Krishna Jagadish,P V Vara Prasad,Peter Q Craufurd,Rico Gamuyao,Maduraimuthu Djanaguiraman,Rajeev N Bahuguna

doi:10.3389/fpls.2016.00913

Abstract

Flowering is a crucial determinant for plant reproductive success and seed-set. Increasing temperature and elevated carbon-dioxide (e[CO2]) are key climate change factors that could affect plant fitness and flowering related events. Addressing the effect of these environmental factors on flowering events such as time of day of anthesis (TOA) and flowering time (duration from germination till flowering) is critical to understand the adaptation of plants/crops to changing climate and is the major aim of this review. Increasing ambient temperature is the major climatic factor that advances flowering time in crops and other plants, with a modest effect of e[CO2].Integrated environmental stimuli such as photoperiod, temperature and e[CO2] regulating flowering time is discussed. The critical role of plant tissue temperature influencing TOA is highlighted and crop models need to substitute ambient air temperature with canopy or floral tissue temperature to improve predictions. A complex signaling network of flowering regulation with change in ambient temperature involving different transcription factors (PIF4, PIF5), flowering suppressors (HvODDSOC2, SVP, FLC) and autonomous pathway (FCA, FVE) genes, mainly from Arabidopsis, provides a promising avenue to improve our understanding of the dynamics of flowering time under changing climate. Elevated CO2 mediated changes in tissue sugar status and a direct [CO2]-driven regulatory pathway involving a key flowering gene, MOTHER OF FT AND TFL1 (MFT), are emerging evidence for the role of e[CO2] in flowering time regulation.

Highlights

The Intergovernmental Panel on Climate Change Reports (e.g., IPCC, 2007, 2013) document evidence of increasing carbon-dioxide concentrations (e[CO2]) and other greenhouse gases leading to a higher frequency of extreme climate events such as heat waves and drought events
Flowering time is defined here as the duration starting from seed germination till appearance of the first floral bud, open flower or anthesis
All the above functions can be affected by climate change; flowering time is one of the major factors determining the adaptation of plants to changing climate

Summary

Introduction

The Intergovernmental Panel on Climate Change Reports (e.g., IPCC, 2007, 2013) document evidence of increasing carbon-dioxide concentrations (e[CO2]) and other greenhouse gases leading to a higher frequency of extreme climate events such as heat waves and drought events. In several grass species it was demonstrated that e[CO2] delayed flowering by 2–7 days and high temperature (1.5◦C above ambient) accelerated flowering by 2–5 days; in combination elevated [CO2] completely overcame the accelerated flowering time observed with increased temperature, i.e., a zero net change (Cleland et al, 2006).

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