Climate dependent control of water loss in leaves

Background and Goals

This project focuses on the question how barley plants will be able to withstand increasing stress induced by the climate change and how to avoid harvest losses by heat and drought. The primary objectives are to find general mechanisms for optimized stoma regulation of barley plants and to identify related marker genes that will help Bavarian breeders to grow high yielding and stress tolerant barley species.

Content time


Research area/region

  • Germany
Region of implementation (all German federal states)
  • Bavaria

Steps in the process of adaptation to climate change

Step 1: Understand and describe climate change

Parameter (climate signals)
  • Heat waves
  • Dry periods

Step 2a: Identify and assess risks - climate effects and impact

Approach and results 

In Bavaria too, climate change is leading to more frequent periods of heat and drought. To counter this, the water management of crops is a size to be improved. Water loss occurs in plants via stomata in the leaves. The stoma opening width, due to the two involved guard cells (SZ), determines the water loss. An optimized water balance under drought stress is therefore crucially dependent on the reaction of the stomata. Here, the stress hormone abscisic acid (ABA) plays a key role.

Step 3: Develop and compare measures

Measures and/or strategies 

The project showed that the stoma closure, a first response to ABA, works faster for barley than for non-grasses and is due to the interaction of closing and secondary cells (NZ). The elucidation of the communication between these two cell types should therefore ultimately help breeders to grow climate-adapted barley varieties. For this purpose, in the barley reference species "bark", the genes identified by a method called RNAseq were identified, which are used specifically in closing cells and those in secondary cells. The processes in the stoma movement in SZ and NZ are controlled in opposite directions.

Important candidates were then functionally characterized. Thus, a model for the nature and regulation of stomata in barley could be established. This model was then tested under stress and with ABA treatment and confirmed on breeding lines. In the field trial special stress-tolerant and sensitive breeding lines were found. By comparing genes used in these strains with the specific inclusion of ABA regulated genes, drought tolerance markers should be identified and made available to breeders.


Funding / Financing 

Bavarian State Ministry of the Environment and Consumer Protection

Project management 

University of Würzburg

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