ACCLIMATIZATION OF WITHANIA SOMNIFERA (L.) DUNAL IN VÂLCEA COUNTY, ROMANIA: OVERWINTERING, REGROWTH AFTER REPEATED CUTTING, AND THE FOLIAGE AND ROOTS OF SECOND-SEASON PLANTS

Rezumat

Withania somnifera (L.) Dunal (Solanaceae) is a frost-tender perennial subshrub that is cultivated as an annual crop, and no quantitative data on its overwintering in Central or Eastern Europe were found. At the applied study site of Asociația Comunitară Beica-Mădulari (Vâlcea County, Romania), plants raised from seed and planted in 30 L bags on 1 June 2025
were grown in a polyethylene tunnel and overwintered in 2025–2026 in two lots of 100 plants: one with thermostat-controlled soil heating (estimated minimum at the collar about +2 °C) and one without heating, under an agrotextile cover (about −2 °C). Survival was 80 % and 50 %, respectively (Fisher's exact test, p < 0.001; one lot per treatment, observational design); an
unprotected outdoor plant did not survive. The plants regrew from the collar in March 2026, tolerated removal of the whole aerial part at about 10 cm every three months, and set seed with 60% emergence. After 16 months, plants lifted from the bags had roots at least 34–45 cm long, collar diameters of 21–25 mm and 23.5–36.5 g fresh mass, with signs of container restriction. Leaves formed after winter dormancy were harvested and dried for a proposed paired leaf–root withanolide analysis