Ion content, antioxidant enzyme activity and transcriptional response under salt stress and recovery condition in the halophyte grass Aeluropus littoralis.

Objective: In contrast to glycophytes, halophyte plants have evolved unique morphological and physiological mechanisms to deal with abiotic stress. This study presents the physiological responses of Aeluropus littoralis, a halophyte grass, to salt stress and recovery conditions on the molecular level.

Results: Elemental analysis showed that Na concentration increased in the analyzed tissue during salt stress application, and declined at recovery condition. With the exception of root tissue, comparable trends of K, Ca, and Mg concentrations were observed (decreased during salt stress, increased during recovery). Salinity led to an increase in total chlorophyll (Chl), Chl a, and carotenoids content, while Chl b content decreased. The level of the proline amino acid associated with drought and salt stress was increased. Here APX, POD, and SOD activity were strongly detectable in roots and reduced later under recovery conditions. RT-qPCR revealed up-regulation of antioxidant genes at S1 and S3 in the root but down-regulation in recovery conditions. This study found a significant halophyte index for understanding the processes of salinity tolerance in A. littoralis. These findings may provide insight into the role of antioxidant enzymes during salt stress and the mechanism underlying the plant's response to stress.