Tag: Rubén Milla

The contribution of upper leaf sides to maximum stomatal conductance was statistically higher in cultivated than in wild ancestors

Shifts in stomatal traits following the domestication of plant species

Milla R., de Diego-Vico N., Martın-Robles N. (2013)

Rubén Milla, Natalia de Diego-Vico, Nieves Martín-Robles,


Departamento de Biología y Geología, Área de Biodiversidad y Conservación, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, c/Tulipán s/n, Móstoles 28933, Spain

Journal of Experimental Botany 64: 3137–3146 – DOI: 10.1093/jxb/ert147 –

https://pubmed.ncbi.nlm.nih.gov/23918960/

Erratum in

  • J Exp Bot. 2013 Dec;64(18):5770

Abstract

Stomata are the major gates regulating substrate availability for photosynthesis and water loss. Although both processes are critical to yield and to resource-use efficiency, we lack a comprehensive picture on how domestication and further breeding have impacted on leaf stomata. To fill this gap, stomatal sizes and densities were screened in cultivated and wild ancestor representatives of a uniquely large group of 24 herbaceous crops. Anatomical data and gas-exchange models were combined to compute maximum potential conductance to water, separately for upper and lower leaf sides. The evolution of maximum conductance under domestication was diverse. Several crops increased, others decreased (noticeably high-conductance species), and others kept a similar potential conductance following domestication. It was found that the contribution of upper leaf sides to maximum conductance was statistically higher in cultivated than in wild ancestors. For crops showing this response, reduced stomatal density in the lower side of domesticated leaves was responsible for the observed ‘adaxialization’ of conductance. Increases in the size of stomata at the upper epidermis played a comparatively minor role. Nevertheless, this overall response was varied in magnitude and direction, signalling crop-wise specificities. Observed patterns reflect only potential conductances based on anatomical traits and should be used with care until actual physiological outcomes are measured. Together with advancements in the developmental genetics of stomata, our findings might hint at new breeding avenues, focused on stomata distribution. Provided urgent needs for increasing yields, the opportunities of enhancing traits of the physiological relevance of stomata should not be ignored.

Stomatal conductance and stomatal density

Photo credit: Google

Pore size regulates operating stomatal conductance, while stomatal densities drive the partitioning of conductance between leaf sides

by Fanourakis D., Giday H., Milla R., Pieruschka R., Kjaer K. H., Bolger M., Vasilevski A., Nunes-Nesi A., Fiorani F., Carl-Otto Ottosen C-O. (2015)

  1. Dimitrios Fanourakis,
  2. Habtamu Giday,
  3. Rubén Milla,
  4. Roland Pieruschka,
  5. Katrine H. Kjaer,
  6. Marie Bolger,
  7. Aleksandar Vasilevski,
  8. Adriano Nunes-Nesi,
  9. Fabio Fiorani
  10. Carl-Otto Ottosen

in Annals of Botany, Volume 115, Issue, Pp. 555-565 – doi: 10.1093/aob/mcu247

Abstract

Background and Aims Leaf gas exchange is influenced by stomatal size, density, distribution between the leaf adaxial and abaxial sides, as well as by pore dimensions. This study aims to quantify which of these traits mainly underlie genetic differences in operating stomatal conductance (gs) and addresses possible links between anatomical traits and regulation of pore width.

Methods Stomatal responsiveness to desiccation, gs-related anatomical traits of each leaf side and estimated gs (based on these traits) were determined for 54 introgression lines (ILs) generated by introgressing segments of Solanum pennelli into the S. lycopersicum ‘M82’. A quantitative trait locus (QTL) analysis for stomatal traits was also performed.

Key Results A wide genetic variation in stomatal responsiveness to desiccation was observed, a large part of which was explained by stomatal length. Operating gs ranged over a factor of five between ILs. The pore area per stomatal area varied 8-fold among ILs (2–16 %), and was the main determinant of differences in operating gs between ILs. Operating gs was primarily positioned on the abaxial surface (60–83 %), due to higher abaxial stomatal density and, secondarily, to larger abaxial pore area. An analysis revealed 64 QTLs for stomatal traits in the ILs, most of which were in the direction of S. pennellii.

Conclusions The data indicate that operating and maximum gs of non-stressed leaves maintained under stable conditions deviate considerably (by 45–91 %), because stomatal size inadequately reflects operating pore area (R2 = 0·46). Furthermore, it was found that variation between ILs in both stomatal sensitivity to desiccation and operating gs is associated with features of individual stoma. In contrast, genotypic variation in gspartitioning depends on the distribution of stomata between the leaf adaxial and abaxial epidermis.

Read the text: Annals of Botany