Clm. Sgherri et al., ANTIOXIDANT SYSTEM IN SPOROBOLUS-STAPFIANUS - CHANGES IN RESPONSE TO DESICCATION AND REHYDRATION, Phytochemistry, 35(3), 1994, pp. 561-565
Changes in the amounts of ascorbic acid, dehydroascorbic acid and glut
athione and in the levels of related enzyme activities were studied in
Sporobolus stapfianus leaves, a desiccation-tolerant or resurrection
plant, in response to desiccation and rehydration. Detached leaves of
S. stapfianus were rapidly dried for 120 hr at O% rel. hum. A 24 hr de
siccation period was sufficient to achieve extremely low water content
s (0.2%). Dried leaves were then rehydrated for 24 hr. The soluble-pro
tein content decreased after drying but did not increase after rehydra
tion without death ensuing. The enzymes related to the glutathione-asc
orbate cycle reacted differently to the rapid water loss: dehydroascor
bate reductase (EC 1.8.5.1) and glutathione reductase (EC 1.6.4.2) act
ivities increased while ascorbate peroxidase (EC 1.11.1.11) activity d
ecreased. All these enzymes resumed their activities after rehydration
. Oxidative processes were intensified following desiccation and even
more after rehydration: i.e. the H2O2 level and the dehydroascorbate/
ascorbate molar ratio increased in desiccated leaves and even more in
rehydrated leaves, while the oxidized glutathione/reduced glutathione
molar ratio, which decreased in desiccated leaves, reached the control
value with rehydration.