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Allometric growth reflects different allocation patterns and relationships of different components or traits of a plant and is closely related to ecosystem carbon storage. As an introduced species, the growth and carbon storage of Sonneratia apetala are still unclear. To derive allometric relationships of the mangrove S. apetala and to estimate carbon storage in mangrove ecosystems, we harvested 12 individual Sonneratia apetala trees from four different diameter classes in the Futian National Nature Reserve, Guangdong, China. Allometric growth models were fitted. The results showed that diameter at breast height (DBH) and wood density were better variables for predicting plant biomass (including above- and below-ground biomass) than plant height. There were significant power function relationships between biomass and DBH, with a mean allometric exponent of 2.22, and stem biomass accounted for 97% of the variation in S. apetala total biomass. Nearly isometric scaling relationships were developed between stem biomass and other biomass components. To better understand the carbon stocks of the S. apetala ecosystem, we categorized all trees into five age classes and quantified vegetation carbon storage. The S. apetala vegetation carbon storage ranged from 96.48 to 215.35 Mg C ha?1, and the carbon storage significantly increased with stand age. The allometric equations developed in this study are useful to estimate biomass and carbon storage of S. apetala ecosystems.
相似文献L-lysine α-oxidase (LO) is an L-amino acid oxidase with antitumor, antimicrobial and antiviral properties. Pharmacokinetic (PK) studies were carried out by measuring LO concentration in plasma and tissue samples by enzyme immunoassay. L-lysine concentration in samples was measured spectrophotometrically using LO. After single i.v. injection of 1.0, 1.5, 3.0 mg/kg the circulating T1/2 of enzyme in mice varied from 51 to 74 min and the AUC0–inf values were 6.54 ± 0.46, 8.66 ± 0.59, 9.47 ± 1.45 μg/ml × h, respectively. LO was distributed in tissues and determined within 48 h after administration with maximal accumulation in liver and heart tissues. Mean time to reach the maximum concentration was highest for the liver—9 h, kidney—1 h and 15 min for the tissues of heart, spleen and brain. T1/2 of LO in tissues ranged from 7.75 ± 0.73 to 26.10 ± 2.60 h. In mice, plasma L-lysine decreased by 79% 15 min after LO administration in dose 1.6 mg/kg. The serum L-lysine levels remained very low from 1 to 9 h (< 25 μM, 17%), indicating an acute lack of L-lysine in animals for at least 9 h. Concentration of L-lysine in serum restored only 24 h after LO administration. The results of LO PK study show that it might be considered as a promising enzyme for further investigation as a potential anticancer agent.
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