科研之友
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摘要
This study was carried out to develop an efficient in vitro-selection system for water stress tolerance in Argania spinosa (L.). Calli were induced from nodal explants on Murashige and Skoog medium containing half-strength salts, supplemented with 1.0 mg l(-1) alpha-naphthaleneacetic acid and 1.0 mg l(-1) 2,4-dichlorophenoxyacetic acid. Increasing concentrations (0, 5, 10, 20, 30, 40, 50, 60, 70, or 80 g l(-1)) of polyethylene glycol 6000 (PEG 6000) were used to study the effect of simulated water stress on the survival ability of A. spinosa calli. There was a significant reduction in callus growth with increasing concentrations of PEG 6000. Selection for water stress tolerance was achieved by exposing 1-month-old calli to 37.5 g l(-1) PEG 6000 (-0.019 MPa) for 3 months. The mechanism(s) of tolerance in the selected calli were studied biochemically. After 8 d of water stress, K+ and Na+ ion concentrations were unaffected in PEG 6000-selected clones (n = 6). The selected calli also showed a significant increase in H2O2 concentration with increased tolerance to water stress compared to non-PEG 6000-selected calli. The activities of several important anti-oxidant enzymes were measured. The results showed important variations between the PEG 6000-selected and non-selected call. PEG 6000-selected calli show significant increases in the activities of three important anti-oxidant enzymes involved in oxygen metabolism (catalase, peroxidase, and polyphenol oxidase), while superoxide dismutase activity was unchanged. Insignificant increases in malondialdehyde concentration were recorded in the PEG 6000-selected lines compared to the non-PEG 6000-selected calli. The in vitro system described here may be used for in vitro screening for A. spinosa calli that are more tolerant to water stress. Further studies on the performance of plants regenerated from the PEG 6000-stress-selected calli remain to be undertaken to verify the genetic stability of the tolerance induced.
- 出版日期2015-3
