Manipulating stomatal density enhances drought tolerance without deleterious effect on nutrient uptake

Abstract

Summary Manipulation of stomatal density was investigated as a potential tool for enhancing drought tolerance or nutrient uptake.Drought tolerance and soil water retention were assessed using Arabidopsis epidermal patterning factor mutants manipulated to have increased or decreased stomatal density. Root nutrient uptake via mass flow was monitored under differing plant watering regimes using nitrogen‐15 (15N) isotope and mass spectrometry.Plants with less than half of their normal complement of stomata, and correspondingly reduced levels of transpiration, conserve soil moisture and are highly drought tolerant but show little or no reduction in shoot nitrogen concentrations especially when water availability is restricted. By contrast, plants with over twice the normal density of stomata have a greater capacity for nitrogen uptake, except when water availability is restricted.We demonstrate the possibility of producing plants with reduced transpiration which have increased drought tolerance, with little or no loss of nutrient uptake. We demonstrate that increasing transpiration can enhance nutrient uptake when water is plentiful.

Reducing Stomatal Density in Barley Improves Drought Tolerance without Impacting on Yield

“…This may also be a factor in explaining why reductions in stomatal density did not impact on the yield of HvEPF1OE plants. Further explanations include significantly reduced rates of gs and thus water loss in HvEPF1OE plants allowing for more resources to be allocated to the generation of seed and aboveground biomass, at the potential cost to root development, as described previously in Arabidopsis EPF-overexpressing plants (Hepworth et al, 2016), or increased soil water content leading to improved nutrient uptake and gs under water limitation (Van Vuuren et al, 1997;Hepworth et al, 2015). Thus, although not tested in this study, reducing stomatal density may also enhance resource allocation or nutrient uptake capacity under water restriction.…”

“…The vast majority of water is lost from crops via transpiration, and reducing this loss provides a potential route toward improving WUE and conserving soil water levels (Hepworth et al, 2015). To this end, much research into the use of antitranspirants was carried out in the 1960s and 1970s (Davenport et al, 1972).…”

“…Recently several laboratory studies have demonstrated that it is possible to improve drought tolerance and WUE by reducing the frequency of stomata on leaves; by using genetic manipulation or mutation to reduce stomatal density improved WUE has been achieved across several model dicot species including Arabidopsis (Arabidopsis thaliana; Yoo et al, 2010;Franks et al, 2015;Hepworth et al, 2015), poplar (Populus spp. ; Lawson et al, 2014), and tobacco (Nicotiana tabacum; Yu et al, 2008).…”

“…Although their functions somewhat overlap, EPF2 acts earliest in stomatal development to restrict entry of cells into the stomatal lineage, while EPF1 acts later to orient subsequent divisions of meristemoid cells and enforce stomatal spacing through the "one-cellspacing" rule via the inhibition of MUTE expression (Hara et al, 2007;Qi et al, 2017). Manipulation of the expression levels of these peptides in Arabidopsis has led to significant improvements in drought tolerance and WUE in experiments conducted in controlledenvironment plant growth rooms (Doheny-Adams et al, 2012;Hepworth et al, 2015).…”

Determinants of agroforestry adoption as an adaptation means to drought among smallholder farmers in Nakasongola District, Central Uganda

“…Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License Schwabe and Connor, 2012;Hepworth et al, 2015). This phenomenon can be classified into four major types: Meteorological, agricultural, hydrological and socioeconomical drought (Mishra and Singh, 2010;Van Loon and Van Lanen, 2012).…”