Due to combined climate and biodiversity crisis, the sustainable utilization of phytogenetic resources stands as one-way alternative while nutrient management strategies gain an increasing role in agriculture. Building on previous studies regarding the Endangered local endemic of Crete (Greece) Carlina diae (Asteraceae) with medicinal and ornamental value, this investigation focused on its pilot cultivation and fertilization (foliar or root application). Foliar application included chemical fertilizer (conventional) or integrated nutrient management (INM). Root application consisted of chemical fertilizer, biostimulant, or INM with biostimulant. Above-ground biomass content of nutrients, together with leaf chlorophyll fluorescence and colour parameters (SPAD meter, DA meter, Chroma Meter) were determined. The leaf content of chlorophyll, three key antioxidant compounds and minerals’ titers were also assessed. The fertilization scheme did not influence plant growth and visually perceived quality (leaf color and shape). Notably, foliar INM fertilization increased biomass partitioning to inflorescences (harvestable organ for either medicinal or ornamental purposes), and decreased tissue water content (facilitating processing). Considering all three antioxidants together, INM with biostimulant appeared the optimum scheme, being associated with the highest (carotenoids, phenolics) or the second highest (flavonoid) content. In C. diae, therefore, INM fertilization was optimal for upgrading yield (foliar) and herbal quality in terms of antioxidant profile (INM with biostimulant), which might be embraced as an eco-friendly approach for high quality yields.

Herein, we applied DNA Barcoding for the genetic characterization of Sideritis syriaca subsp. syriaca (Lamiaceae; threatened local Cretan endemic plant), using seven molecular markers of cpDNA. Five fertilization schemes were evaluated comparatively in a pilot cultivation in Crete. Chemical fertilizers (ChF), integrated nutrient management fertilizers (INM) and two biostimulants were utilized (foliar and soil application). Plant growth, leaf chlorophyll fluorescence and colour were assessed, and leaf content of chlorophyll, key antioxidants (carotenoids, flavonoids, phenols), and minerals were evaluat-ed. Fertilization regime did not affect leaf colour but induced distinct differences in leaf shape altering quality characteristics. INM-foliar and ChF-soil application promoted yield, without affecting tissue water content or biomass partitioning to inflorescences. ChF-foliar application was the most stimulato-ry treatment for enhanced antioxidant compound content, while INM-biostimulant was the least effec-tive one. In conclusion, adverse fertilization options appear as optimal when considering yield or anti-oxidant compound content. New DNA sequence datasets for the plastid regions of petB/petD, rpoC1, psbK-psbI and atpF/atpH have been deposited in the GenBank for S. syriaca subsp. syriaca while the mo-lecular markers rbcL, trnL/trnF, psbA/trnH were compared to those of another 15 Sideritis species re-trieved from the GenBank, constructing a phylogenetic tree to show their genetic relatedness.