Abstract
Plants acclimate to drought optimizing the trade-off between biomass production and water loss while ensuring their survival and reproduction. Plants also modify their growth or phenology as complementary strategies in response to stress. Despite evidence of an interaction between flowering time and plant growth response to environmental stresses, this interaction in response to drought is under debate. To contribute to the analysis of this interaction, leaf growth of 35 genetically modified lines of Arabidopsis thaliana and their common wild-type, Col-0 was analyzed by a quantitative multi-scale phenotyping approach from cellular to whole plant scale both in wellwatered and soil moderate water deficit conditions. These genotypes were selected for the various physiological functions potentially altered by their genetic modification and that could interact with plant growth and/or their drought responses. In all genotypes, leaf expansion decreased in response to drought both at the whole rosette and the individual leaf levels. Additionally, epidermal cell area and/or epidermal cell number decreased in response to the drought treatment. In contrast, the number of rosette leaves was reduced in only half of the genotypes and leaf growth duration was only modified in 4 of them. Despite long photoperiod conditions, the duration of the vegetative phase, i.e. the time elapsed between germination and flowering stage, varied from 12 to 27 days among genotypes under well watered conditions. Our analyses revealed that the differences of flowering time observed in well-watered condition impacted the leaf area response to drought. Early-flowering genotypes slightly decreased their final leaf number, but strongly reduced their
Highlights
Understanding how plants are facing drought stress is a central concern and it has been the subject of many studies and reviews [1]-[3]
The duration of the vegetative phase is related to many other shoot growth related variables, including the number of leaves produced by the plant [15], more intriguingly individual leaf expansion and epidermal cell expansion in individual leaves [18] [20]
We explored the relationships between the duration of the vegetative phase and the leaf growth performance in response to a moderate soil water deficit condition
Summary
Understanding how plants are facing drought stress is a central concern and it has been the subject of many studies and reviews [1]-[3]. The molecular control of this adaptation to a mild water deficit at the leaf scale differs from the ones reported for severe drought stresses or osmotic shocks [2] [8] [11] [12]. Different populations of recombinant inbred lines have been studied to identify Quantitative Trait Loci that control leaf growth response to soil water deficit [15]-[19]. These studies led to the identification of many flowering time related polymorphisms. A delay in flowering date causes an increase in leaf number, in the duration of leaf expansion, and in epidermal cell area in leaves, and all these changes interact to impact whole shoot development and leaf expansion
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