Physiological response to drought of a giant woody cabbage cross (Brassica oleracea)


Background and context

In the context of climate change and the higher probability of extreme climate events such as droughts and heatwaves, more research is needed to understand and predict how plants will react to these stressful events. In particular, crop species are crucial systems in which to develop this knowledge, and they will allow us to investigate the traits regulating resilience to increased drought tolerance. A cross of two cabbages with contrasting growth forms and life history traits (the rapid flowering dwarf TO1000 and the late flowering giant woody ‘walking stick’ Jersey Kale) offers the opportunity to look for interesting key traits in the F2 population, such as stem woodiness, leaf water potential, leaf turgor loss point, embolism resistance in stems and leaves, hydraulic safety margin, and stomatal conductance, among others.

Fig 1. Contrasting woody-herbaceous grandparent lines of Brassica oleracea (left) are crossed into an F2 population (right) showing variation in woodiness and plant size.

Objectives and goals

This project aims to determine the differences in water-use behavior and hydraulic traits related to drought-tolerance between the two parents and a number of offspring genotypes selected to represent the range of variability in stem woodiness.

Material and methods

Multiple individuals of each accession – the two parents, and a selected number of F2 individuals that show contrasted levels of drought tolerance – will be grown from tissue culture to mature height. Different drought levels will be applied by reducing or by simply stop the daily watering rates. Parameters such as daily minimum and stem water potential, stomatal conductance, CO2 assimilation, leaf turgor loss point, photosynthetic rate and sap-flow will be monitored throughout the experiment. Following this drought period, plants will be re-watered and their recovery dynamics measured for the same set of parameters. Lethal water potential (level of drought that kill the plants) will also be determined this way.


We are looking for a student with an interest in plant anatomy, physiology and hydraulic function during drought. Experience growing and caring for plants is desired.

For more information:


[1] Tyree, M. T. & Ewers, F. W. The hydraulic architecture of trees and other woody plants. New Phytol. 119, 345–360 (1991).

[2] Bartlett, M. K., Klein, T., Jansen, S., Choat, B. & Sack, L. The correlations and sequence of plant stomatal, hydraulic, and wilting responses to drought. Proc. Natl. Acad. Sci. 113, 13098–13103 (2016).

[3] Lens, F. et al. Herbaceous angiosperms are not more vulnerable to drought-induced embolism than angiosperm trees. Plant Physiol. pp.00829.2016 (2016).

[4] Brodribb, T. J., Powers, J., Cochard, H. & Choat, B. Hanging by a thread? Forests and drought. Science 368, 261–266 (2020).

[5] Dayer, S. et al. The sequence and thresholds of leaf hydraulic traits underlying grapevine varietal differences in drought tolerance. J. Exp. Bot. 71, 4333–4344 (2020).

[6] Thonglim, A. et al. Intervessel pit membrane thickness best explains variation in embolism resistance amongst stems of Arabidopsis thaliana accessions. Ann. Bot. 128, 171–182 (2020).


Supervisor and contact

Dr. Frederic Lens (group leader Functional Traits, Naturalis Biodiversity Center,

Dr. Giovanni Bortolami (postdoc Functional Traits, Naturalis Biodiversity Center,

Ms. Ajaree Thonglim (PhD student Functional Traits, Naturalis Biodiversity Center,

Period and duration

Ca. 6 months, project can start now

Study and level

MSc project