Multiple abiotic stress, nitrate availability and the growth of wheat

Abstract

Highlights Leaf elongation is lower when roots are impeded irrespective of nitrate supply. Root impedance and soil drying have a similar impact on root and shoot grow. We found genotypic effects in leaf stunting due to abiotic stress. Root diameter decreases with decreasing nitrate availability. Root diameter increases with root impedance and moderate soil drying.

Green revolution ‘stumbles’ in a dry environment: Dwarf wheat with Rht genes fails to produce higher grain yield than taller plants under drought

“…However, under drought, the availability of nitrogen in soil at the root surface is reduced and impaired due to three main processes: nitrogen mineralisation, mass flow and diffusion (Sadras et al, 2016). In such conditions, plants attempt to reach deeper soil with more moisture and nitrogen (Barraclough, Kuhlmann, & Weir, 1989), and their growth is more dependent on root impedance in dry and compacted soil (Ge et al, 2019). Therefore, in dry fields, the application of nitrogen fertilizer caused a small or even negative effect for wheat yield compared to those in well-watered favourable seasons (Angus, Gupta, Pitson, & Good, 2014).…”

Wheat growth responses to soil mechanical impedance are dependent on phosphorus supply

“…The co-ordination of growth between wheat shoot and root has been shown in several papers. Nodal root number is positively correlated with plant height ( Colombi and Walter, 2017 ), leaf number ( Klepper et al, 1984 ), and tiller number ( Ge et al, 2019 ), and total root length shows strong correlation with leaf area ( Jin et al, 2015 ). The restricted shoot growth could be related to the reduced P uptake in the impeded plants.…”

“…The sand column system that was employed to investigate the effects of mechanical impedance and P availability on wheat growth is described in previous studies ( Ge et al, 2019 ; Jin et al, 2015 ). Rigid plastic tubes of 45 cm in length and 15 cm in diameter were placed in tanks of nutrient solution on a base with a mesh lining.…”

“…The porosity of the sand is approximately 30 % and it is not affected by the application of the weight, because the sand is not compressible at these confining pressures. Our previous work showed that the sand column system can precisely control the mechanical impedance independently of other properties of the growing medium, such as aeration and water status ( Clark et al, 2002 ; Coelho Filho et al, 2013 ; Ge et al, 2019 ). When a steel weight is placed on the surface of a sand column, the mechanical impedance is increased because confining pressure makes it harder to expand cavities.…”

“…When a steel weight is placed on the surface of a sand column, the mechanical impedance is increased because confining pressure makes it harder to expand cavities. However, there is negligible compressibility of the sand under the weight, and the application of the weight had a minimal effect on density ( Ge et al, 2019 ). In this study we used sand from a geological deposit; such sands do not deform until confining pressures exceed 1000 kPa ( Cheng et al, 2001 ).…”