Relationships between foliar carbon isotope discrimination with potassium concentration and ash content of the riparian plants in the extreme arid region of China

Abstract

Carbon isotope discrimination (Δ) has been proposed as an indirect estimation criterion for water use efficiency in C 3 plants. Because of the higher cost for Δ analysis, ash content or K concentration has been proposed as an alternative criterion for Δ in many species. In five typical habitats of the extreme arid Ejina desert oasis in northwest of China, the seasonal variations of foliar Δ, ash content, and potassium (K) concentration were researched in two constructive desert riparian plants (Populus euphratica Olivier, Tamarix ramosissima Ledeb). The correlations of foliar Δ with ash content and K concentration in both species were also examined to evaluate the feasibility of the foliar ash content and K concentration as surrogates of Δ in P. euphratica and T. ramosissima. Results showed that there were significant effects of plant species, habitats and growth season on foliar Δ, ash content, and K concentration. Foliar Δ and K concentration in P. euphratica were significantly higher than those in T. ramosissima, whereas, the ash content was reverse. Among habitats, the trends of Δ signatures in both P. euphratica and T. ramosissima were similar, Δ values and ash content in both species were the lowest in the dune. Both in the Gobi and dune sites, K concentration in P. euphratica and T. ramosissima was different. In the whole growth period, foliar Δ values and ash content in both species were gradually increased, but K concentration was decreased. Ash content was significantly and positively related to Δ in both P. euphratica and T. ramosissima. However, significantly negative correlations between foliar Δ and K concentration as well as between ash content and K in P. euphratica were found. In T. ramosissima, the relationship was positive but very weak.

Relationships between foliar carbon isotope composition and elements of C3 species in grasslands of Inner Mongolia, China

“…Relationships between d 13 C and C Previous studies have reported negative correlations between d 13 C and ash or mineral content (Cao et al 2009;Merah et al 2001;Zhao et al 2007;Zhu et al 2010). Generally, C was negatively correlated with ash or mineral content (Zhou et al 2013).…”

“…However, while Cao et al (2009) and Zhao et al (2007) found negative relationships between d 13 C and K for Tamarix ramosissima, Artemisia ordosica, and Hedysarum scoparium, as well, they also found positive relationships for Populus euphratica and Caragana korshinskii.…”

“…Further, foliar element ratios, e.g., C/N (foliar carbon:nitrogen ratio), C/P (foliar carbon:phosphorus ratio), and N/P (foliar nitrogen:phosphorus ratio), are also key traits of ecological relevance and link with d 13 C through their correlation with water use efficiency (WUE). For example, Cernusak et al (2010) observed a positive correlation between leaf N/P ratio with WUE and that with d 13 C. However, previous studies have suggested that relationships between foliar d 13 C and elements differ for study areas and plant species (Cao et al 2009;Zhao et al 2006Zhao et al , 2007Zhou et al 2013). For example, although most studies have reported that d…”

“…Thus, investigating the relationships between d 13 C and nutrient elements is important for ascertaining potential mechanisms of plant adaptation to arid and semiarid environments and the main factors limiting plant growth. Although some previous studies have undertaken related research in arid regions, they have mostly involved a limited number of tree or shrub species and have not involved grassland herb species (Cao et al 2009;Zhao et al 2006Zhao et al , 2007.…”

Relationships between C3 Plant Foliar Carbon Isotope Composition and Element Contents of Grassland Species at High Altitudes on the Qinghai-Tibet Plateau, China

“…Mg, which occupies the center of the porphyrin nucleus of the chlorophyll molecule, has an important function in activating enzymes related to the synthesis of protein, RNA and DNA [21]. In addition, a negative correlation between ash content and δ 13 C has been widely observed [22]–[27]. This is because minerals are mostly passively transported in plant organs via the xylem flux and accumulated in place, so a plant that needs more water for the same biomass accumulation (lower δ 13 C) would be proportionally richer in minerals (higher ash content).…”