Spirodela oligorrhiza

APase in onion roots. Enzyme activity was mainly extracellular with the heaviest concentration in corner spaces between the epidermal and hypo-dermal layers. He suggested the possibility of a subcutaneous pore through which the enzyme could be released to the root surface. Bieleski and co-workers (Reid Bieleski, 1970 Bieleski Johnson, 1972) studied the psi induction and location of APase in duckweed (Spirodela oligorrhiza). APase in control plants was located primarily in and around the vascular strands. In P-deficient plants psi-APase activity was 10-20 times the control value. Enzyme activity was primarily located in the epidermis of the root and undersurface of the frond, the tissue locations most likely to provide access to phosphate esters in the medium. These workers further demonstrated that hydrolysis of organic phosphates occurred in the external medium and/or the apoplast followed by Pi uptake into the cell. 

Bieleski, R.L. Johnson, P.N. (1972). The external location of phosphatase activity in phosphorus-deficient Spirodela oligorrhiza. Australian Journal of Biological Sciences 25, 707-20. 

The release of ethylene was shown to increase upon exposure of flowering plants to heavy-metal containing solutions, e.g. citms fruit (Ben-Yehoshua and Biggs, 1970), beans (Abeles and Abeles, 1972 Fuhrer, 1982 Gora and Clijsters, 1989), Spirodela oligorrhiza (Mattoo et al., 1986), soybeans (Pennazio and Roggero, 1991), tomatoes (Bouzayen et al., 1991) and rice (Peng and Yamauchi, 1993 Kao, 1996). 

Mattoo, A.K., Baker, J.E., Moline, H.E., 1986. Induction by copper ions of ethylene production in Spirodela oligorrhiza Evidence for a pathway independent of 1-aminocyclopropane-l-carboxylic acid. J. Plant Physiol. 123, 193-202. 

Figure 3. A miniplant system for pre-screening for herbicide protectants. Effects of benzyl viologen after 24h continuous co-treatment with diquat using Spirodela oligorrhiza as outlined in [24). Benzyl viologen also protects pea plants from paraquat (Shaaltiel, Gillham, Dodge and Gressel, unpublished results). Unpublished photograph of Lewinsohn and Gressel.

The incorporation of P02 into lipids of Spirodela oligorrhiza L. was reported by Bieleski (1972). After the rapid labeling and turnover of PA, the highest label (and specific activity) was in PG, but after 10 h PE and PC were more heavily labeled than PG. There was a marked difference in phosphate-deficient plants, where PC was always the most heavily labeled phospholipid. Phosphate-deficient plants have visibly different chloroplasts there is an accumulation of starch, and 60% less phospholipid than in normal chloro-... 

Morita, N., Nakazato, H., Okuyama, H., Kim, Y., and Thompson, G. A., Jr. (1996) Evidence for a glycosylinositolphospholipid-anchored alkaline phosphatase in the aquatic plant Spirodela oligorrhiza, Biochim. Biophys. Acta 1290, 53-62. 

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