Root hydraulics: The forgotten side of roots in drought adaptation

Vadez, V (2014) Root hydraulics: The forgotten side of roots in drought adaptation. Field Crops Research, 165 (1). pp. 15-24. ISSN 0378-4290

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Abstract

Roots have long been proposed as a major avenue of research to improve crop adaptation to water limitations. The simple assumption is that deeper and more profuse root systems could tap extra water from the soil profile and alleviate drought effects. However, after decades of research, success in breeding cultivars with improved root systems is lagging behind. Here, we attempt to analyze the possible reasons for this, and re-focus on what root traits might provide the most promising avenues for drought adaptation. We approach the root system from the angle of water extraction, using data from a lysimetric system that allows monitoring and comparing plant water use over the entire crop life cycle and yield, and analyze whether and how differences in water extraction lead to improved yield across different crops. The main message from that analysis is that water extraction during reproduction and grain filling is critical and comes from a number of traits that influence the rate at which plant use the available water before and during stress. Roots may have an effect on this, not from the traditionally thought density or depth, but rather from their hydraulic characteristics. Plants can indeed control water use by controlling leaf area development and this is a “long term” control. Plants also control water losses by controlling stomata opening under high vapor pressure deficit (VPD) conditions, in a transient manner. Both processes (leaf development and stomata opening) are mostly controlled by hydraulic processes. The role of roots in drought adaptation could be there, along with the soil, in setting an hydraulic environment that allow plants to use water in a way that allow maximizing water use for these critical stages.

Item Type: Article
Divisions: RP-Dryland Cereals
CRP: CGIAR Research Program on Dryland Cereals
CGIAR Research Program on Grain Legumes
Uncontrolled Keywords: Water extraction; Lysimeters; Vapor pressure deficit; Xylem vessel; Root cylinder; Aquaporin
Subjects: Others > Plant Physiology
Depositing User: Mr Siva Shankar
Date Deposited: 29 Apr 2014 08:39
Last Modified: 29 Dec 2016 10:31
URI: http://oar.icrisat.org/id/eprint/7918
Official URL: http://dx.doi.org/10.1016/j.fcr.2014.03.017
Projects: Generation Challenge Program (TropicalLegume Project), Blue Sky Research project onAquaporins
Funders: Government of India - Department of Biotechnology, Australian Center for International Agriculture Research(ACIAR), Bill and Melinda Gates Foundation, ICRISAT
Acknowledgement: The author would like to acknowledge support from the Department of Biotechnology, Government of India (Center of Excellence in Genomics), for partial support to the development of the lysimetric facility presented in this paper, a facility that has contributed to re-casting our view on the contribution of root to drought adaptation. The authors also acknowledge support from the Australian Center for International Agriculture Research (ACIAR) (CIM-2007-120), from the Bill and Melinda Gates Foundation G6007-01 through the Generation Challenge Program (Tropical Legume Project), and from ICRISAT (Blue Sky Research project on Aquaporins).
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