Drought Tolerance is Associated with Rooting Depth and Stomatal Control of Water Use in Clones of Coffea canephora

Abstract

With irrigation, plant hydraulic conductance (K(L)), midday psi(x) and total biomass were all greater in clones 109A and 120 than in the other clones. Root mass to leaf area ratio was larger in clone 109A than in the others, whereas rooting depth was greater in drought-tolerant than in drought-sensitive clones. Predawn psi(x) of -3.0 MPa was reached fastest by 109A, followed progressively by clones 46, 120 and 14. Decreases in g(s) with declining psi(x), or increasing evaporative demand, were similar for clones 14, 46, and 120, but lower in 109A. Carbon isotope ratio increased under drought; however, it was lower in 109A than in other clones. For all clones, psi(x), g(s) and K(L) recovered rapidly following re-watering. Differences in root depth, K(L) and stomatal control of water use, but not osmotic or elastic adjustments, largely explained the differences in relative tolerance to drought stress of clones 14 and 120 compared with clones 46 and 109A.

Genotypic variation in soil water use and root distribution and their implications for drought tolerance in chickpea

“…In summary, when water is not limited plants prefer to utilise water more from surface soil layers (Ludlow and Muchow 1990). Plants are forced to mine deeper soil layers only when water is limited (Serraj et al 2004;Pinheiro et al 2005;Yu et al 2007;Manschadi et al 2010;Hammer et al 2009Hammer et al , 2010Wasson et al 2012;Comas et al 2013;Krishnamurthy et al 2013;Lynch 2013;Steele et al 2013). For example, in modelling exercises of soil water utilisation the root system had been considered to extract 40% of the total transpiration from the top quarter of root zone, even if the top layer is desiccated by evapotranspiration (Molz and Remson 1970) that was also confirmed to occur in chickpea (Krishnamurthy et al 1999(Krishnamurthy et al , 2010Serraj et al 2004;Kashiwagi et al 2015).…”

Ecophysiology of coffee growth and production

“…This architectural pattern also seems to be similar for conilon coffee (Rena and DaMatta, 2002). In any case, the root system of both coffee species is highly plastic and its distribution and length are also age-dependent (Inforzato and Reis, 1973;Brangança, 2005), in addition to varying with planting density (Cassidy and Kumar, 1984;Rena et al, 1998), genotypes (Alfonsi et al, 2005;Pinheiro et al, 2005;Cavatte et al, 2008), soil characteristics (Rena and DaMatta, 2002), cultural practices (Sáiz del Rio et al, 1961;Cassidy and Kumar, 1984;Rena and DaMatta, 2002;Barreto et al, 2006), and weed competition .…”

Up-regulation of a H + -pyrophosphatase (H + -PPase) as a strategy to engineer drought-resistant crop plants

“…Engineering plants with drought avoidance characteristics, i.e., that reduce the negative impact of soil water deficits on productivity by maintaining a more favorable plant water status, has been limited (8). Some naturally occurring droughttolerant plant species seem to employ deep and dense root systems to maximize water uptake (9)(10)(11)(12)(13)(14)(15). Despite their obvious role in water uptake, roots have not been targeted in genetic engineering strategies to improve crop performance under drought conditions (16).…”