Seedling Survival Strategies of Zanthoxylum planispinum ‘Dintanensis’ and Zanthoxylum amatum ‘Novemfolius’, Based on Functional Traits in Karst Desertification Control

Abstract

The exploration of the functional traits of Zanthoxylum planispinum ‘dintanensis’ and Zanthoxylum amatum ‘novemfolius’ at the seedling stage may provide a scientific basis for the zoning of germplasm resources and the introduction of plant varieties. The seedlings of the above mentioned two species with an age of about 8 months were selected as the study material, and the structure, nutrients, and physiological traits of leaves and roots were determined, respectively, to reveal their survival strategies. The results demonstrated the following four key elements. (1) The leaf thickness, specific leaf area, and leaf δ15N value of Z. planispinum ‘dintanensis’ were significantly higher than those of Z. amatum ‘novemfolius’ (p < 0.05). However, the root diameter and Ca content showed the opposite results, and the other traits were not significantly different. (2) Leaf functional traits except Ca, as well as specific root length, and root P, Ca, and physiological traits had strong dominant effects on the functional trait system. (3) Among the main functional traits, leaf K and root P preferred environmental selection, leaf C, N, and P favored stable inheritance, and specific leaf area, leaf δ15N, and root Ca were affected by varieties. (4) There were significant synergies (promotion) and trade-offs (inhibition) between the functional traits, and the leaves and the root system were closely correlated. It is speculated that Z. planispinum ‘dintanensis’ may have a stronger defense system. Its leaves are mainly related to growth and defense functions, and its roots are mainly related to the regulation of functions.