C:N:P Stoichiometry and Leaf Traits of Halophytes in an Arid Saline Environment, Northwest China

Abstract

Salinization is an important and increasingly prevalent issue which has broad and profound effects on plant survival and distribution pattern. To understand the patterns and potential drivers of leaf traits in saline environments, we determined the soil properties, leaf morphological traits (specific leaf area, SLA, and leaf dry matter content, LDMC), leaf chemical traits (leaf carbon, C, nitrogen, N, and phosphorus, P, stoichiometry) based on 142 observations collected from 23 sites in an arid saline environment, which is a vulnerable ecosystem in northwest China. We also explored the relationships among leaf traits, the responses of leaf traits, and plant functional groups (herb, woody, and succulent woody) to various saline environments. The arid desert halophytes were characterized by lower leaf C and SLA levels, higher N, but stable P and N:P. The leaf morphological traits were correlated significantly with the C, N, and P contents across all observations, but they differed within each functional group. Succulent woody plants had the lowest leaf C and highest leaf N levels among the three functional groups. The growth of halophytes might be more limited by N rather than P in the study area. GLM analysis demonstrated that the soil available nutrients and plant functional groups, but not salinity, were potential drivers of leaf C:N:P stoichiometry in halophytes, whereas species differences accounted for the largest contributions to leaf morphological variations. Our study provides baseline information to facilitate the management and restoration of arid saline desert ecosystem.

Seasonal Variations in Carbon, Nitrogen and Phosphorus Concentrations and C:N:P Stoichiometry in the Leaves of Differently Aged Larix principis-rupprechtii Mayr. Plantations

“…Comparison of our results with those of other studies in which samples were collected in July or July-August revealed that the leaf C:N ratios of all larch stands were higher than those of the arid saline biomes of China (15.7 ± 5.6) [24] and the global value (23.8 ± 17.3) [25,26]. Furthermore, the leaf C:P ratios were higher than those of the arid saline biomes of China (229.4 ± 63.7) [24] but lower than the global value (300.9 ± 236.8) [25,26].…”

“…Furthermore, the leaf C:P ratios were higher than those of the arid saline biomes of China (229.4 ± 63.7) [24] but lower than the global value (300.9 ± 236.8) [25,26]. In addition, the leaf N:P ratios were lower than those of Chinese flora (16.3 ± 9.3) [18], the arid saline flora of China (15.4 ± 3.7) [24], the desert flora of northern China (15.77 ± 7.5) [27] and the global value (13.8 ± 9.5) [25,26] (Table 5 and Table S3). The differences in the leaf C:N, C:P and N:P ratios among different studies are likely due to differences in ecosystem type, sampling time, abiotic factors (such as temperature, elevation, precipitation, and drought) [25] and biological factors [26].…”

“…Across all of the larch stands, the leaf C concentrations (leaves sampled in July) and the mean leaf C concentrations (leaves sampled in July-September) were higher than those of the arid saline biomes of China (396.7 ± 45.4 mg·g −1 ) [24] and the global value (461.3 ± 72.2 mg·g −1 ) [25,26], but the leaf N concentrations (leaves sampled in the same month) were generally lower than those of Chinese flora (20.2 ± 8.4 mg·g −1 ) [18], the arid saline biomes of China (28.1 ± 9.4 mg·g −1 ) [24], the global value (20.1 ± 8.7 mg·g −1 ) [25,26] and the desert regions of northern China (24.5 ± 8.1 mg·g −1 ) [27]. However, the leaf P concentrations of all larch stands (leaves sampled in the same month) were generally higher than those of Chinese flora (1.46 ± 0.99 mg·g −1 ) [18], the global flora (1.77 ± 1.1 mg·g −1 ) [25,26] and the desert flora of northern China (1.74 ± 0.88 mg·g −1 ) [27] (Tables 2 and S3).…”

Stoichiometric variation of halophytes in response to changes in soil salinity

“…Moreover, one study also suggested that what drove the variation in halophytes leaf N:P stoichiometry was the available nutrients in the soil rather than the salt concentration (Wang et al . ). Saline stress can also reduce the accumulation of K, Ca and Mg, as well as K:Na ratio in leaves, while increasing Na in some experiments (Khan et al .…”

Leaf N and P stoichiometry in relation to leaf shape and plant size for Quercus acutissima provenances across China

“…Indeed, chemical elements are the basic principles of stoichiometry5. Leaf shape and plant size are key aspects of plant morphological performance, which can provide general information about plant growth and investment strategies34. Therefore, it is imperative to explore the relationships between leaf stoichiometry and leaf shape and plant size.…”