A simple general method to evaluate intra-specific transpiration parameters within and among seedling families

Abstract

A method to evaluate the genetic control of plant response to increasing soil water deficit is proposed. A description of single tree transpiration behavior was obtained considering parameters independent from air and soil conditions. We removed environmental effects by using two approaches: the normalization of drought data to control (watered) plants and the fitting of a process model. We analyzed the transpiration of 475 4-year-old European beech seedlings, belonging to eight full-sib families. Approximately, one-third of the seedlings were kept in well-watered conditions while the others were exposed to drought for 14 days. Daily plant transpiration was estimated as the difference between two subsequent gravimetric measurements. A mechanistic model was fitted to transpiration data separately for each tree. In the model, the relationship of transpiration with vapor pressure deficit and soil water deficit of each tree is modulated by three parameters: maximum leaf conductance (gM1), maximum transpiration in well-watered soil conditions E(M0)1 and a parameter describing stomatal sensitivity to soil water deficit (c). The model successfully fitted most single tree data and a distribution of estimates for the three parameters (gM1, E(M0)1 and c) was obtained. Predicted transpiration values were in good agreement with observed data (R (2) = 0.86). The model approach produced parameters significantly correlated with those of the "normalization to control" approach. Estimated parameters vary considerably among trees, suggesting the presence of individual differences in stomatal behavior and response to drought. In spite of a large among tree (within family) variation, the among families component for gM1, E(M0)1 and c explained 9.5, 3.3 and 0.1% of total parameters variation suggesting a significant genetic control of transpiration processes.

Variation in photosynthetic performance and hydraulic architecture across European beech (Fagus sylvatica L.) populations supports the case for local adaptation to water stress

“…This finding tallies with other studies showing high intrapopulation variability in functional traits of European beech, which in some cases can exceed the variability among populations (Ramfrez-Valiente et al 2009, Aranda et al 2010, Bresson et al 2011. For instance, Leonardi et al (2006) recorded high differentiation in the control of water loss in response to water Water potential (MPa)…”

“…2006), genotypic variation (i.e., differences in the genome between individuals) or both. Although genetic variation has been claimed to be of lower relevance than plasticity for adjustment of some functional traits in beech (Bresson et al 2011), other studies indicate that intraspecific genetic variability in highly dynamic functional traits, such as those controlling transpiration, can have an important cumulative effect on whole-plant performance (Leonardi et al 2006). Thus, both phenotypic plasticity and genetic variability in functional traits can be considered relevant mechanisms for adaption to drought (Meier and Leuschner 2008, Rose et al 2009, Bresson et al 2011).…”

Orchestration of transpiration, growth and carbohydrate dynamics in rice during a dry-down cycle

“…An emerging experimental standard is dry-down pot experiments in controlled environments. This enables to gravimetrically monitor bulk soil moisture content (Reymond et al 2003;Tardieu et al 2005) and at the same time, if soil evaporation is suppressed, whole-plant transpiration rate (Rouphael and Colla 2004;Leonardi et al 2006). Using this setup, other plant drought responses can be measured and their dynamics related to current drought intensity in terms of the fraction of transpirable soil water (FTSW; Lecoeur and Guilioni 1998;Pellegrino et al 2005).…”

Adjustment of hydraulic, anatomical and leaf traits in Fagus sylvatica (L.) towards drier conditions. A study in mature stands.

“…In correspondence with earlier studies, the portion of leaf trait variance attributed to unexplained within-population as well as within-tree differences was high in the studied leaf traits (Leonardi et al, 2006;.…”