Abstract
(1) Background: The study analyzed wheat morphological traits to assess the role of roots structure in the tolerance of drought and to recognize the mechanisms of root structure adjustment to dry soil environment. (2) Methods: Root-box and root-basket methods were applied to maintain an intact root system for analysis. (3) Results: Phenotypic differences among six genotypes with variable drought susceptibility index were found. Under drought, the resistant genotypes lowered their shoot-to-root ratio. Dry matter, number, length, and diameter of nodal and lateral roots were higher in drought-tolerant genotypes than in sensitive ones. The differences in the surface area of the roots were greater in the upper parts of the root system (in the soil layer between 0 and 15 cm) and resulted from the growth of roots of the tolerant plant at an angle of 0–30° and 30–60°. (4) Conclusions: Regulation of root bending in a more downward direction can be important but is not a priority in avoiding drought effects by tolerant plants. If this trait is reduced and accompanied by restricted root development in the upper part of the soil, it becomes a critical factor promoting plant sensitivity to water-limiting conditions.
Highlights
Roots, as one of the primary organs, play an important role in vascular plants
Our research focused on both aspects in an attempt to recognize: (1) The role of root structure in soil drought tolerance, and (2) the mechanisms of root structure adjustment to the surrounding soil environment in order to increase competitiveness of water uptake by plant roots in dry conditions
Wheat genotypes used in our study showed a wide range of drought tolerance traits in previous experiments [26]
Summary
As one of the primary organs, play an important role in vascular plants. They are a hidden part of a plant, responsible for growth, development and productivity, anchorage, and supplying stem and leaves with water and nutrients [1,2,3,4,5,6,7,8]. Root system structure (RSS) is defined as a spatial configuration of roots in the soil profile (refers to the shape and physical space of the roots) and is controlled genetically [12,13,14]. The RSS consists of several components, such as seminal, seminal adventitious, nodal, and lateral roots. Individual components of one Plants 2019, 8, 584; doi:10.3390/plants8120584 www.mdpi.com/journal/plants
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