Root morphological plasticity determing the adaptive strategies of Cotinus coggygria seedlings in barren soil environment

Morphological plasticity is closely related to the ability of plant growth and resource utilization, which is an important manifestation of plant survival strategy in specific environment. To study the relationship between root morphological plasticity and ecological strategies of the plant is significant to understand the mechanism of plant adaptation to the environment. With 1-year-old Cotinus coggygria seedlings as the study materials, this paper applies the pot experiment in greenhouse and sets up five different levels of nutrient supply to analyze the root morphology characteristics (root length, surface area, root tissue density, root fineness, root branching density, etc.) and different diameters of root morphology (root length, root surface area, root volume, root tips) to study the changes of morphological and functional plasticity in the plant seedlings. The results indicated that different levels of nutrient supply showed significant (P < 0.01) interaction on root length, surface area, root tips, root forks, root tissue density, average root diameter and root fineness of the plant seedlings. In the pure sand environment, the seedlings were most closely related to the root length, root surface area and root fineness. In the environment with limited nutrient restriction, the seedlings were mainly changed by root length, root surface area, root number and branch. However, the relationship between root tip density, root branch density, root diameter and root volume was most closely related in the relatively light and medium environment. In the whole soil environment, the seedlings were mainly affected by the change of root tissue density. To a certain extent, limited nutrient supply can stimulate ≤1.0 mm diameter fine roots and limit >1.0 mm diameter fine roots. Morphological and functional plasticity in the plant seedlings reflected that the levels of nutrient supply significantly changed the strategies of nutrient absorption of Cotinus coggygria seedlings. From nutrient-sufficient to nutrient-limited and nutrient-deficient condition, seedlings tend to change their ecological strategies from enhancing the utilization ability in situ, enhancing the absorption ability in situ and expanding the absorption range, improving the storage and transportation ability, and finally change to the endurance strategies.