5. Conclusion
Using tissue culture under carefully controlled environmental
conditions, we determined the direct effect of salt stress and light
on antioxidant system in tomato fruit, and found that changes in
the ASA content and activities of antioxidant enzymes in tomato
fruit exposed to salt stress cannot be accounted for by salt stress
alone. Several interactions between salt stress and light intensity
were observed in in vitro fruits (Table 1), and high, but notlow, light
intensity modulates antioxidant systems in salt-stressed tomato
fruit. We propose that enhancing the ASA content by the application
of salt should account for the combined effects of salt stress and
light conditions on the ASA content and antioxidant system. However,
because the light intensities studied here are relatively low
compared with natural conditions, further studies under natural
light intensities are desirable.
Acknowledgment
This study was supported by a Grant-in-Aid for Young Scientists
(B) (No. 21780234) from the Japan Society for the Promotion of
Science.