Differing Trade-Off Patterns of Tree Vegetative Organs in a Tropical Cloud Forest

Yuanyuan Yang; Chuchu Xiao; Xianming Wu; Wenxing Long; Guang Feng; Guoying Liu

doi:10.3389/fpls.2021.680379

Differing Trade-Off Patterns of Tree Vegetative Organs in a Tropical Cloud Forest

Front Plant Sci. 2021 Jul 21:12:680379. doi: 10.3389/fpls.2021.680379. eCollection 2021.

Authors

Yuanyuan Yang^{1

2

3}, Chuchu Xiao^{1

2

3}, Xianming Wu⁴, Wenxing Long^{2

3}, Guang Feng^{2

3}, Guoying Liu^{2

3}

Affiliations

¹ College of Ecology and Environment, Hainan University, Haikou, China.
² National Positioning Observation and Research Station of Forest Ecosystem, College of Forestry, Hainan University, Haikou, China.
³ Key Laboratory of Tropical Forest Flower Genetics and Germplasm Innovation, Ministry of Education, Haikou, China.
⁴ Bawangling Branch, Hainan Tropical Rainforest National Park Administration, Changjiang, China.

Abstract

Functional trait ecology demonstrates the significance of the leaf economics spectrum in understanding plants' trade-off between acquisitive and conservative resource utilization. However, whether trait variations of different vegetative organs are coordinated and whether the plant economics spectrum is characterized by more than one vegetative organ remain controversial. To gain insights into these questions, within a tropical cloud forest in Hainan Island, a total of 13 functional traits of 84 tree species were analyzed here, including leaf, stem and root traits. By using standardized major axis (SMA) regression and principal components analysis, we examined the trait variations and correlations for deciphering plants' trade-off pattern. We found decreases of leaf phosphorus content, leaf nitrogen content and specific leaf area and increases of leaf mass per unit area (LMA), wood density and leaf thickness along the first principal component, while there were decreases of specific root length and specific root area and increases of root tissue density along the second principal component. Root phosphorus and nitrogen contents were significantly positively associated with the phosphorus and nitrogen contents of both stem and leaf. Wood density was significantly positively associated with LMA and leaf thickness, but negatively associated with leaf thickness and specific leaf area. Our results indicate that, in the tropical cloud forest, there is a "fast-slow" economic spectrum characterized by leaf and stem. Changes of nutrient trait are coordinated, whereas the relationships of morphological traits varied independently between plant above- and below-ground parts, while root nutrient traits are decoupled from root morphological traits. Our findings can provide an insight into the species coexistence and community assembly in high-altitude tropical forests.

Keywords: above- and below-ground correlations; morphological trait; nutrient traits; plant economic spectrum; resource use strategy.