Beyond rest and quiescence (endodormancy and ecodormancy): A novel model for quantifying plant–environment interaction in bud dormancy release

Abstract

Bud dormancy of plants has traditionally been explained either by physiological growth arresting conditions in the bud or by unfavourable environmental conditions, such as non‐growth‐promoting low air temperatures. This conceptual dichotomy has provided the framework also for developing process‐based plant phenology models. Here, we propose a novel model that in addition to covering the classical dichotomy as a special case also allows the quantification of an interaction of physiological and environmental factors. According to this plant–environment interaction suggested conceptually decades ago, rather than being unambiguous, the concept of “non‐growth‐promoting low air temperature” depends on the dormancy status of the plant. We parameterized the model with experimental results of growth onset for seven boreal plant species and found that based on the strength of the interaction, the species can be classified into three dormancy types, only one of which represents the traditional dichotomy. We also tested the model with four species in an independent experiment. Our study suggests that interaction of environmental and physiological factors may be involved in many such phenomena that have until now been considered simply as plant traits without any considerations of effects of the environmental factors.

A Conceptual Framework for Winter Dormancy in Deciduous Trees

“…Forestry studies on phenology prediction resulted in interesting advances, offering alternatives to the traditional chill-heat models currently used in agricultural sciences. These models account for the relationships between photoperiod and temperature [55,56], or even allow the Agronomy 2020, 10, 241 8 of 20 quantification of an interaction of physiological and environmental factors in addition to considering them separately [57].…”

Latitudinal clines in bud flush phenology reflect genetic variation in chilling requirements in balsam poplar, Populus balsamifera

“…Part of the complexity in unraveling the G×E response is that spring bud flush is actually the culmination of two distinct, yet interacting, underlying physiological processes-rest and quiescence-which operate in conjunction to control plant responsiveness to temperature at different stages of dormancy (Samish, 1954;Lundell et al, 2019). Plants first enter a state of rest once buds are fully hardened at the end of the previous growing season and will remain in a state of rest unless they experience an accumulation of near-freezing temperatures, often quantified as cumulative chilling degree days (cCDD), which promotes the process of rest break.…”

“…Plants first enter a state of rest once buds are fully hardened at the end of the previous growing season and will remain in a state of rest unless they experience an accumulation of near-freezing temperatures, often quantified as cumulative chilling degree days (cCDD), which promotes the process of rest break. Once sufficient chilling has accumulated and the bud reaches a state of rest completion, typically by midwinter, plants transition to a state of quiescence, where ontogenetic growth within the bud occurs at a rate dependent on the air temperature (some species also possess an interaction with photoperiod) until the growth causes bud flush (Heide, 1993;Lundell et al, 2019). However, the transition between rest and quiescence can be gradual and nondiscrete, with chilling needs still being met at the same time that heat sums start to accumulate, resulting in an overlap of these two stages (Way, 2011;Guy, 2014;Lundell et al, 2019).…”

Extending the Cultivation Area of Pecan (Carya illinoinensis) Toward the South in Southeastern Subtropical China May Cause Increased Cold Damage

“…This is where our study deviated most from the study of Zhang et al (2021c), which we otherwise followed closely in building the model on the basis of experimental data. We solved the problem following Lundell et al (2020), who also had just one controlled chilling temperature in their experiment:…”