Adaptive changes in root morphological traits of Gramineae and Leguminosae seedlings in the ecological restoration of the semiarid region of northwest China

Gramineae and Leguminosae forages are widely grown in the semiarid region of northwest China. To understand the changes in root morphology in forage seedlings under drought stress, a nursery experiment was conducted with and without water stress using four Gramineae species ( Bromus inermis , Agropyron mongolicum , Lolium perenne , and Bothriochloa ischaemum ) and four Leguminosae species ( Lespedeza bicolor , Medicago sativa , Astragalus adsurgens and Melilotus suaveolens ). The forages were grown in rhizoboxes under drought stress (15% polyethylene glycol stress) and well‐watered (85% of field capacity) conditions. The results showed that the root length, root area, and specific root length of the Gramineae species were higher than those of the Leguminosae species at the 30–60 cm soil depth. The fine roots of eight species in the 0~0.5 mm diameter class had the largest total root length and total root area, and the total root volume and root tips in the 0.5~1.0 mm diameter class were the highest. Based on the subordinate function method results, B. inermis had the highest comprehensive score, while M. suaveolens had the lowest. Our results implied that Gramineae seedlings distributed more roots than Leguminosae seedlings in the 30–60 cm soil layer under drought stress. Under drought stress, fine roots in the 0~0.5 mm and 0.5~1.0 mm diameter classes were the main organs sustaining the growth of the eight species when suffered drought stress. Among the eight species, B. inermis had the strongest drought tolerance and could act as an optimal ecological restoration forage in the semiarid region of northwest China

Agronomy · Biology · Botany · Bromus inermis · Drought Tolerance · Forage · Lespedeza · Lolium perenne · Melilotus · Poaceae · Agronomic Practices and Intercropping Systems · Plant Molecular Biology Research · Plant nutrient uptake and metabolism