Journal of Hunan Ecological Science

【Objective】Tree absorptive roots are mainly responsible for providing nutrients and water for plant growth and development. The main purpose of this study is to explore the response of tree ab- sorptive roots’ morphology and anatomical traits with seasons, which is conducive to in-depth understand- ing of the nutrient acquisition strategies of trees in different seasons. 【Method】In this study, the roots of five tree species (Elaeocarpus glabripetalus, Magnolia denudata, Manglietia fordiana, Pteroceltis tatari- nowii, Lithocarpus calophyllus) in Nanyue mountainous region were collected in spring, summer, autumn and winter, and the morphological characteristics and anatomical structure of 1st-5th roots of different tree species in different seasons were determined. 【Result】The results showed that absorptive roots’ morphol- ogy and anatomical traits were significantly affected by tree species, root order and season. With the in- crease of root order, the diameter increased, correspondingly with the decrease of specific root length, the decrease of cortical thickness, the increase of stele diameter and the decrease of the ratio of cortical thickness to stele radius. Compared with other seasons, in summer trees had the highest absorptive roots diameter and the highest proportion of the number of absorptive roots, as well as the highest cortical thickness and stele diameter; the absorptive roots characteristics in winter were opposite to those in sum- mer. For example, the first-order roots of Manglietia fordiana were the thickest in summer (300. 40 ± 9. 54 μm) and the thinnest in winter (184. 32±9. 62 μm). The cortex thickness and stele diameter of the first-order roots of Lithocarpus calophyllus were also the highest in summer, which were 55. 04 ± 2. 85 μm and 73. 39±3. 80 μm, respectively, and these two indexes decreased by 47% in winter. In ad- dition, this seasonal variation pattern was basically consistent among the different order roots in five tree species, which might be related to the climate, resource conditions and tree growth needs in different sea- sons. 【Conclusion】The study shows that tree absorptive roots can adapt to environmental changes in dif- ferent seasons by adjusting the morphology and anatomical traits, which is of great theoretical significance for revealing the resource acquisition strategies of tree absorptive roots in different seasons, optimizing for- est nutrient management and improving forest productivity in different seasons.

Nanyue mountainous region; seasonal changes; absorptive roots; morphology; anatomical structure