LAUSR

Ashwagandha (W. somnifera Dunal. Linn.), known as Indian ginseng, contains three major bioactive compounds, withaferin-A (WA), 12-deoxywithastramonolide (WO) and withanoloide A (WD). In a field experiment, the impacts of foliar application of growth retardants/promoters was assessed with respect to biomass allocation pattern and major withanoloide content at different phenological stages in W. somnifera. Biomass accumulation pattern showed that foliar application of 500 mg l−1ethrel at 50, 65, 85, 105, and 120 days after sowing (DAS) restricted phenological progression and reduced berry weight by 61% as comparted to the control at 160 DAS. 500 mg l−1 succinic acid foliar application resulted in maximum plant height (56.4 cm), maximum dry stem weight (DWS) and dry root weight (DRW) whereas 500 mg l−1 ethrel had resulted in minimum plant height and DRW at 180 DAS. During last 50 days of crop growth, the accumulation pattern drastically changed with more than 60% of the biomass allotment to the reproductive part, the berries. The WD in roots ranged between 0.325 mg g−1and 0.342 mg g−1 during all growth stages. WA content decreased with increase in progression of crop growth and reached the lowest at 180–190 DAS. In a pot experiment, ethrel application up regulated DWF-5 by 2.44, SQE by 3.79 and CYP450s by 1.17 log2fold in roots 8 h after treatment and succinic acid had up regulated the expression of all these genes by nearly 3 log2fold change. This is in accordance with the withanoloide accumulation pattern in field condition under foliar application of these molecules.