Morpho-anatomical adaptations of two Tagetes erecta L. cultivars with contrasting response to drought stress

Water deficit is a serious threat to the global crop production. Marigold (Tagetes erecta L.), an economically important annual is resistant to drought stress, however, anatomical adaptations confirming drought tolerance are still unexplored. In this context, key growth and anatomical difference of two marigold (T. erecta L.) cultivars, Inca (drought resistant) and Bonanza (drought sensitive), to water deficit conditions were studied. Plants of both marigold cultivars were subjected to control (T-0; 100% FC) and water deficit conditions (T-1; 60 FC and T-2; 40 FC) three weeks after transplantation. Drought stress caused a significant reduction in growth of cv. Bonanza while cv. Inca remained unaffected. However, drought stress significantly affected anatomical features in both marigold cultivars. Increasing drought stress levels enhanced the reduction in root vascular area of both cultivars. Under both levels of water stress, shoot cortex area decreased only in cv. Bonanza. Leaf thickness and cortex area decreased at 40% FC in both cultivars. The growth and biomass performance of cv. Inca was better than cv. Bonanza under water stress conditions.