What triggers phenological events in plants under seasonal environments? A study with phylogenetically related plant species in sympatry.

C C Pereira,M G Boaventura,T Cornelissen,Y R F Nunes,G C De Castro

doi:10.1590/1519-6984.257969

Abstract

In this study, we evaluated variation in vegetative and reproductive phenological events of four phylogenetically related plant species subjected to a seasonal environment. To this aim, we sampled 15 individuals of each plant species every fortnight for one year, between January and December of 2017. To assess when a given phenophase occurred more intensely in the population, the Fournier intensity index was used and the synchrony of individuals of the sample in a given phenological event was estimated using the activity index. The Rayleigh (Z) test was used to determine whether the phenological events have seasonal distribution. The relationship of abiotic factors (photoperiod, precipitation, relative humidity and temperature) with the intensity of phenophases was evaluated for each plant species using generalized linear models (GLMs). The phenophases of all plants showed a seasonal distribution pattern, as well as variation in synchrony of phenophases and specific sets of abiotic factors significantly influenced their phenophases. New leaves, for example, were produced throughout the seasons, with intense leaf fall in the dry season. Flowering periods, on the other hand, did not overlap. Indeed, species exhibited sequential flowering and asynchronous flowering among individuals. Our results suggest that the phenological patterns of four sympatric plant species are directly linked to climatic variables, but different abiotic factors affected different phenophases.

Highlights

Plant phenophases are intimately related to climate (Lieth, 2013) and temperature is one of the main drivers of plant phenology in vegetations worldwide
Zoochoric fruits are usually produced along the year, allowing for a greater supply of resources for frugivores, whereas anemochoric or autochoric fruits are produced during the dry season, when conditions are more favorable to diasporte dispersion (Kuhlmann and Ribeiro, 2016)
To test the above-mentioned hypotheses, we investigated the vegetative and reproductive phenophases of these plant species for one year and evaluated how different climatic variables influenced the triggering of these phenophases

Summary

Introduction

Plant phenophases are intimately related to climate (Lieth, 2013) and temperature is one of the main drivers of plant phenology in vegetations worldwide (e.g., tropical forests: Lima et al, 2021; savannas: Vilela et al, 2017). For instance, leaf fall is generally concentrated in the dry season (Williams et al, 1997; Novaes et al, 2020) and leaf flushing, which is less seasonal, can occur in both the dry and wet seasons (Lacerda et al, 2018). Phenological adaptations in these harsh environments include flowering in the dry season, when plants become more visible to mutualistic animals due to leaf fall (Williams et al, 1997), or flowering at the very beginning of the rainy season (just before the heavier rains) a strategy to avoid flower damage (Novaes et al, 2020). Zoochoric fruits are usually produced along the year, allowing for a greater supply of resources for frugivores, whereas anemochoric or autochoric fruits are produced during the dry season, when conditions are more favorable to diasporte dispersion (Kuhlmann and Ribeiro, 2016)

Methods

Results

Conclusion