Bioactive Compounds, Antioxidant Activity, and Mineral Content of Wild Rocket (Diplotaxis tenuifolia L.) Leaves as Affected by Saline Stress and Biostimulant Application

Featured Application The results of the present work provide useful insights into the response of Diplotaxis tenuifolia L. plants to salinity stress and biostimulant application under successive crop cycles. Considering the complex effects of biostimulants on vegetable crops, providing new information regarding the positive effects of this agronomic practice under salinity stress and variable growing conditions will be useful for farmers and crop production stakeholders in their efforts to address the increasing soil salinization and degradation of the quality of irrigation water. The availability of irrigation water of good quality is decreasing due to soil salinization and the deterioration of aquifers. Moreover, ongoing climate change severely affects crop production and necessitates the intensification of cropping systems in order to ensure food security at a global scale. For this purpose, the aim of the present study was to evaluate the mitigating effects of two natural biostimulants on Diplotaxis tenuifolia L. plants cultivated at different salinity levels (EC of 0 dS m(-1), 2 dS m(-1), 4 dS m(-1), and 6 dS m(-1)) and harvested at six consecutive cropping cycles. The tested factors showed a varied combinatorial effect on the tested parameters. These findings indicate the importance of considering growing conditions and cropping periods when applying biostimulants in D. tenuifolia plants under salinity stress. Antioxidant activity and bioactive compounds, such as total phenols, carotenoids, and total ascorbic acid, were variably affected by salinity, biostimulant application, and harvesting time, while mineral profile was also affected by the tested factors depending on the combination of factors. Finally, nitrate content showed decreasing trends with increasing salinity, while biostimulant application resulted in the higher accumulation of nitrates compared to the untreated plants. Although biostimulant application seems to alleviate the negative effects of salinity stress, the effect of growing conditions, as indicated by successive crop cycles, is also important for the response of D. tenuifolia plants to saline conditions and biostimulant application.

Automated summary

The results of this study provide valuable insights into the response of Diplotaxis tenuifolia L. plants to salinity stress and biostimulant application. The findings highlight the importance of considering growing conditions and cropping periods when applying biostimulants under salinity stress. The effect of biostimulants on antioxidant activity, bioactive compounds, mineral profile, and nitrate content depends on the combination of factors.