39 research outputs found
Limitation of grassland productivity by low temperature and seasonality of growth
The productivity of temperate grassland is limited by the response of plants to low temperature, affecting winter persistence and seasonal growth rates. During the winter, the growth of perennial grasses is restricted by a combination of low temperature and the lack of available light, but during early spring low ground temperature is the main limiting factor. Once temperature increases, growth is stimulated, resulting in a peak in growth in spring before growth rates decline later in the season. Growth is not primarily limited by the ability to photosynthesize, but controlled by active regulatory processes that, e.g., enable plants to restrict growth and conserve resources for cold acclimation and winter survival. An insufficient ability to cold acclimate can affect winter persistence, thereby also reducing grassland productivity. While some mechanistic knowledge is available that explains how low temperature limits plant growth, the seasonal mechanisms that promote growth in response to increasing spring temperatures but restrict growth later in the season are only partially understood. Here, we assess the available knowledge of the physiological and signaling processes that determine growth, including hormonal effects, on cellular growth and on carbohydrate metabolism. Using data for grass growth in Ireland, we identify environmental factors that limit growth at different times of the year. Ideas are proposed how developmental factors, e.g., epigenetic changes, can lead to seasonality of the growth response to temperature. We also discuss perspectives for modeling grass growth and breeding to improve grassland productivity in a changing climate
Photorespiration: metabolic pathways and their role in stress protection
Photorespiration results from the oxygenase reaction catalysed by ribulose-1,5-bisphosphate carboxylase/
oxygenase. In this reaction glycollate-2-phosphate is produced and subsequently metabolized in the
photorespiratory pathway to form the Calvin cycle intermediate glycerate-3-phosphate. During this metabolic
process, CO2 and NH3 are produced and ATP and reducing equivalents are consumed, thus
making photorespiration a wasteful process. However, precisely because of this ine¤ciency, photorespiration
could serve as an energy sink preventing the overreduction of the photosynthetic electron transport
chain and photoinhibition, especially under stress conditions that lead to reduced rates of photosynthetic
CO2 assimilation. Furthermore, photorespiration provides metabolites for other metabolic processes, e.g.
glycine for the synthesis of glutathione, which is also involved in stress protection. In this review, we
describe the use of photorespiratory mutants to study the control and regulation of photorespiratory pathways.
In addition, we discuss the possible role of photorespiration under stress conditions, such as
drought, high salt concentrations and high light intensities encountered by alpine plants
Phenotypic plasticity masks range-wide genetic differentiation for vegetative but not reproductive traits in a short-lived plant
Genetic differentiation and phenotypic plasticity jointly shape intraspecific trait variation, but their roles differ among traits. In short-lived plants, reproductive traits may be more genetically determined due to their impact on fitness, whereas vegetative traits may show higher plasticity to buffer short-term perturbations. Combining a multi-treatment greenhouse experiment with observational field data throughout the range of a widespread short-lived herb, Plantago lanceolata, we (1) disentangled genetic and plastic responses of functional traits to a set of environmental drivers and (2) assessed how genetic differentiation and plasticity shape observational trait-environment relationships. Reproductive traits showed distinct genetic differentiation that largely determined observational patterns, but only when correcting traits for differences in biomass. Vegetative traits showed higher plasticity and opposite genetic and plastic responses, masking the genetic component underlying field-observed trait variation. Our study suggests that genetic differentiation may be inferred from observational data only for the traits most closely related to fitness
Phenotypic plasticity masks range-wide genetic differentiation for vegetative but not reproductive traits in a short-lived plant
Publication history: Accepted - 19 May 2021; Published - 5 August 2021.Genetic differentiation and phenotypic plasticity jointly shape intraspecific trait
variation, but their roles differ among traits. In short-lived
plants, reproductive
traits may be more genetically determined due to their impact on fitness, whereas
vegetative traits may show higher plasticity to buffer short-term
perturbations.
Combining a multi-treatment
greenhouse experiment with observational field
data throughout the range of a widespread short-lived
herb, Plantago lanceolata,
we (1) disentangled genetic and plastic responses of functional traits to a set of
environmental drivers and (2) assessed how genetic differentiation and plasticity
shape observational trait–environment
relationships. Reproductive traits showed
distinct genetic differentiation that largely determined observational patterns, but
only when correcting traits for differences in biomass. Vegetative traits showed
higher plasticity and opposite genetic and plastic responses, masking the genetic
component underlying field-observed
trait variation. Our study suggests that genetic
differentiation may be inferred from observational data only for the traits
most closely related to fitness.Eesti Teadusagentuur, Grant/Award
Number: PRG609 and PUT1409; Academy
of Finland; Natural Sciences and
Engineering Research Council of Canada;
Science Foundation Ireland, Grant/Award
Number: 15/ERCD/2803; Spanish Ministry
of Science, Innovation and Universities,
Grant/Award Number: IJCI-2017-
32039;
European Regional Development Fun