Studies on leaf functional traits in key protected plants of Myristicaceae

To study the ecological adaptation strategies of key protected plants (KP) in the tropics, this study focused on nine woody plants within the Myristicaceae family, including five KP and four non-KP (NKP) species. Twenty-two traits were measured, including leaf morphology, gas exchange, nutrient concentration, and nutrient resorption efficiency. Results showed that compared to NKP plants, KP plants exhibited lower leaf dry matter content, leaf density, and carbon concentration, but thicker leaves and higher maximum photosynthetic rate on a leaf area basis. However, leaf mass per area, leaf vein density, stomatal conductance, nutrient concentration, and nutrient resorption efficiency did not differ significantly between the plants. Additionally, nitrogen (N) concentration was positively associated with N resorption efficiency. Magnesium (Mg) concentration was negatively correlated with leaf mass per area in KP plants, and Mg resorption efficiency and leaf vein density were negatively correlated in both KP and NKP plants. Principal component analysis revealed that the first principal component was primarily associated with leaf density, photosynthetic N use efficiency, and leaf dry matter content, while the second principal component was mainly associated with N and phosphorus (P) concentrations and the N∶P ratio. The leaf N∶P ratio of Myristicaceae plants was below 14, indicating N-limitation rather than P-limitation to their growth. These findings suggest that studies based on functional traits can reveal differences in ecological adaptation strategies between KP and NKP plants. Further comparative eco-physiological studies should be conducted between KP and NKP plants.