Main content area

Mycorrhizal and non-mycorrhizal dicotyledonous herbaceous plants differ in root anatomy: evidence from the Middle Urals, Russia

Betekhtina, Anna A., Veselkin, Denis V.
Symbiosis 2019 v.77 no.2 pp. 133-140
Apiaceae, Asteraceae, Caryophyllaceae, Lamiaceae, Polygonaceae, cortex, fungi, herbaceous plants, morphogenesis, mycorrhizae, nutrients, root systems, roots, symbionts, Russia
Mycorrhiza is an important factor in plant morphogenesis, especially in root formation. It has been shown that mycorrhizal and non-mycorrhizal plants differ in root length and diameter; however, the underlying anatomical features have been poorly described. In the present work, we analysed functionally divergent roots of 28 species of dicotyledonous herbaceous plants (the Apiaceae, Asteraceae, Caryophyllaceae, Lamiaceae, and Polygonaceae families) from the Middle Urals, Russia. Based on our data and those of previous reports, we divided all species into three groups, non-mycorrhizal (6 species), mycorrhizal (9), and variable mycorrhizal (13), and compared general characteristics of their root systems and anatomical features of the finest roots. The root system of non-mycorrhizal plants was more branched compared to mycorrhizal, which possibly facilitates the uptake of water and mineral nutrients in the absence of fungal symbionts. The main difference was that the cortex of the mycorrhizal species’ roots was significantly thicker due to 4–6 cell layers while those of non-mycorrhizal had no more than 4 layers. Moreover, the cortex was apparently retained for a relatively long time. Analysis of variable mycorrhizal plants revealed intermediate values between two contrast groups. We suggest that a greater number of cortical cell layers in the finest roots and a prolonged retention of the cortex are intrinsic for mycorrhizal species; nevertheless, further research is needed to assess whether it is applicable to other dicotyledonous plant species.