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Effects of nitrogen and phosphorus supply on stoichiometry of six elements in leaves of Arabidopsis thaliana.
Yan, Z, Hou, X, Han, W, Ma, S, Shen, H, Guo, Y, Fang, J
Annals of botany. 2019;(3):441-450
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Abstract
BACKGROUND AND AIMS Plant elemental composition is of fundamental importance for plant growth and metabolic functions. However, knowledge of how multi-elemental stoichiometry responds to varying nitrogen (N) and phosphorus (P) availabilities remains limited. METHODS We conducted experimental manipulations with nine repeat experiments to investigate the effects of N and P supply on the concentrations and variability of six elements, carbon (C), N, P, potassium (K), calcium (Ca) and magnesium (Mg), in leaves of Arabidopsis thaliana. KEY RESULTS N supply increased the concentrations of N, K and Mg, decreased the concentration of P, but exerted little influence on the concentrations of C and Ca in green leaves. P supply increased the concentrations of P and Ca, decreased the concentration of C, initially increased and then decreased the concentration of K, but showed little influence on the concentrations of N and Mg in green leaves. Multivariate patterns among the concentrations of these six elements in green leaves was influenced by the type of nutrient supply (i.e. N or P). Elemental variability decreased with increasing elemental concentrations in green leaves at the intraspecific level, supporting the Stability of Limiting Elements Hypothesis that was originally proposed from a meta-analysis of pooled data across species or communities. Compared with green leaves, the senesced leaves showed greater variability in C, N, P, K and Mg concentrations but lower variability in Ca concentration. CONCLUSIONS N and P supplies exerted differential influences on the concentrations of C, N, P, K, Ca and Mg in green leaves. The specific C content should be considered when assessing C cycling under global nutrient changes. Stage-dependent patterns of leaf stoichiometric homeostasis differed among elements with various chemical characteristics. These findings can help to improve our understanding of plant eco-physiological responses and acclimation under global nutrient changes from the stoichiometric perspective of multiple elements.
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Altered nutrition state in the severe multiple trauma patients undergoing adjuvant recombinant human growth hormone nutritional support therapy.
Guo, Y, Bai, X, Lin, G, Tang, Z
Journal of Huazhong University of Science and Technology. Medical sciences = Hua zhong ke ji da xue xue bao. Yi xue Ying De wen ban = Huazhong keji daxue xuebao. Yixue Yingdewen ban. 2007;(3):299-302
Abstract
In order to observe the nutrition state in the severe multiple trauma patients undergoing adjuvant recombinant human growth hormone (rhGH) nutritional support therapy, 45 patients with severe multiple traumas (ISS>25) were randomly divided into 3 groups. All the 3 groups had been supplied with nitrogen and caloricity according to the need of patients for 16 days. The rhGH therapy started 48 h after surgery and lasted for 14 days in two rhGH-treated groups in which rhGH was 0.2 and 0.4 U/(kg . d) respectively, and the resting group served as control one. The levels of nitrogen balance, prealbumin and safety variables (blood sugar, Na+, TT3 and TT4) were observed and compared among the three groups. The levels of nitrogen balance on the postoperative day (POD) 3 and 5 in the rhGH-treated groups were -1.28+/-3.19, 5.45+/-2.00 and -0.18+/-2.55, 6.11+/-1.60, respectively, which were significantly higher than those in the control group (-5.17+/-1.68 and -1.08+/-3.31, P<0.01). The values of prealbumin on the POD 3 and 5 in the rhGH-treated groups were 180.19+/-27.15, 194.44+/-50.82 and 194.94+/-29.65, 194.11+/-16.17, respectively, which were significantly higher than those in the control group (117.42+/-19.10 and 135.63+/-28.31, P<0.01). There was no significant difference between the rhGH 0.2 U/(kg . d) group and rhGH 0.4 U/(kg . d) group in both of the levels of nitrogen balance and prealbumin. It is concluded that the nutritional support therapy with adjuvant rhGH which starts 48 h after surgery improves the nutrition state of the patients with severe multiple trauma. It is safe for severe multiple trauma patients who accept rhGH at the dose of 0.2 and 0.4 U/(kg . d).