Light intensity and sulfur deficiency modulate growth and water dynamics in broccoli plants via aquaporin regulation

Sulfur plays a critical role in plant secondary metabolism, particularly in the biosynthesis of glucosinolates, where it functions as a core structural element and participates in molecular regulatory mechanisms. Moreover, sulfur metabolism is intricately connected to nitrogen assimilation, highlighting its multifaceted role in plant physiological processes. Light, another key abiotic determinant, directly modulates crop productivity, with light intensity governing essential processes such as growth kinetics and photosynthetic efficiency. This study aims to elucidate the effects of light stress and sulfur deficiency on broccoli (Brassica oleracea var. italica) growth and water dynamics under controlled environment conditions, both individually and in combination, to identify the physiological and molecular mechanisms activated in response to these stressors. The results revealed that sulfur deficiency has a stronger impact on plant water relations than light stress, while light stress mainly affects photosynthetic activity and biomass accumulation. Combined stresses lead to more pronounced physiological responses, including distinct aquaporin regulation patterns that differ from single stress treatments. These findings suggest a compensatory mechanism that helps maintain water balance, highlighting the complex interplay between sulfur availability, light intensity, and plant adaptation strategies.