Affiliation:
1. State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences , Beijing 100093 , China
2. College of Resources and Environment, University of Chinese Academy of Sciences , Beijing 100049 , China
3. Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences , Beijing 100081 , China
Abstract
Abstract
Background and Aims
Grasses and forbs are dominant functional groups in temperate grasslands and display substantial differences in many biological traits, especially in root and stomatal morphologies, which are closely related to the use of water and nutrients. However, few studies have investigated the differences in nutrient accumulation and stomatal morphology-mediated transportation of water and nutrients from roots to shoots comparatively between the two functional groups.
Methods
Here, we explored the patterns of accumulation of multiple nutrients (N, P, K, Ca, Mg and S) in leaves and roots, transpiration-related processes and interactions between nutrients and transpiration at functional group levels by experiments in a temperate steppe and collection of data from the literature.
Key Results
The concentrations of all the examined nutrients were obviously higher in both leaves and roots of forbs than those in grasses, especially for leaf Ca and Mg concentrations. Grasses with dumbbell-shaped stomata displayed significantly lower transpiration and stomatal conductance than forbs with kidney-shaped stomata. In contrast, grasses showed much higher water-use efficiency (WUE) than forbs. The contrasting patterns of nutrient accumulation, transpiration and WUE between grasses and forbs were less sensitive to varied environments. Leaf N, P and S concentrations were not affected by transpiration. In contrast, leaf Mg concentrations were positively correlated with transpiration in forb species. Furthermore, linear regression and principal component analysis showed that leaf Ca and Mg concentrations were positively correlated with transpiration between the two functional groups.
Conclusions
Our results revealed contrasting differences in acquisition of multiple nutrients and transpiration between grasses and forbs, and that stomatal morphologies are an important driver for the distinct WUE and translocation of Ca and Mg from roots to leaves between the two functional groups in temperate steppes. These findings will contribute to our understanding of the important roles of functional traits in driving water and nutrient cycling.
Funder
National Natural Science Foundation of China
Publisher
Oxford University Press (OUP)