The roles of phosphorus (P) starvation on the induction of intracellular acid phosphatase (ACP; EC 3.1.3.2) activity have been studied in a marine macroalga Ulva lactuca L. In comparison to creasy and dark green appearance in P-sufficient thalli (100 mM NaH2PO4), P-starved thalli (1 mM NaH2PO4) showed less crease and light green appearance. On exposure to 1 mM NaH2PO4, the growth rate, the contents of SRP, PP and P, and tissue C:P and N:P molar ratio decreased at day 3 and the contents of SNRP, TSP and polyphosphate decreased immediately. Intracellular ACP activity increased at day 3 after exposure to 1 mM NaH2PO4 and reached 16 folds of P-sufficient thalli at day 14, while extracellular alkaline phosphatase (AP; EC 3.1.3.1) activity increased at day 2 and reached the plateau after 4 days. Activity staining both on Native PAGE and IEF gel showed the induction of 10 and 9 ACP isoenzymes, respectively. Changes in intracellular ACP and extracellular AP activities were negatively correlated with SRP, SNRP, PP and P contents. After transferred to 100 mM NaH2PO4, the growth rate of 10 day-starvated thalli recovered after 5 days, the contents of SRP¡BSNRP¡BTSP and P, and the C:P and N:P molar ratio recovered to the level of P-sufficient thalli at day 1. When recovered to 100 mM NaH2PO4, extracellular AP activity of 10 day-starvated thalli decreased at day 2 and reached the minimum after day 8, while intracellular ACP activity decreased at day 3 and reached the minimum after day 8. The analog of Pi, Phi (1 mM) inhibited the intracellular ACP and extracellular AP activities induced by P swtarvation. The results of present investigation show that ACP has a role in the enhancement of P availability in U. lactuca via the enzymatically degradation of polyphosphates and organic P when suffers P deficiency.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0624103-120726 |
| Date | 24 June 2003 |
| Creators | Tsai, Pei-Fen |
| Contributors | none, none, none, TM LEE |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0624103-120726 |
| Rights | withheld, Copyright information available at source archive |
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