Effects of methyl jasmonate and indole-3-acetic acid on accumulation of picfeltarraenin in Picria felterrae Lour

ObjectiveThe present study was conducted to investigate the impact of methyl jasmonate(MeJA) and in-dole-3-acetic acid(IAA) on accumulation of picfeltrarraenins in planted Picria felterrae Lour. individuals, in order to provide a reference for development of chemical regulation measures for planted individuals of the species. MethodDiffer-ent concentrations of MeJA and IAA solutions were sprayed onto leaf surface and soaked roots of P. felterrae Lour. individu-als, and accumulated amount of picfeltrarraenin IA and IB and total picfeltrarraenins were measured. ResultWhen the concentration of MeJA solution was 20 mg/L, the strongest regulative effect on picfeltrarraenin IA was achieved for both fo-liage spray and root soaking, the accumulative amount of picfeltrarraenin IA reaching the maximum levels, 0.63% and 0.62%respectively, significantly higher than that induced by clean water control(CK)(P<0.05, the same below). MeJA at 2 mg/L showed the strongest stimulative effect on accumulation of picfeltrarraenin IB, and this effect became weakened as the con-centration increased; as regards root soaking, the promoting effect strengthened with increase in MeJA concentration, and accumulative amount of picfeltrarraenin IB reached the highest level 0.34% when concentration was 20 mg/L. The accumula-tive amount of total picfeltrarraenins reached the highest level when the MeJA concentration was 20 mg/L for both treat-ments, the overall effect of foliage spray was better than that of root soaking. For foliage spray with IAA solution, accumula-tive amount of picfeltrarraenin IA decreased firstly and then increased as concentration of IAA solution increased, and reached the maximum level 0.68% at 100 mg/L which was significantly higher than that induced by other concentrations and CK. For root soaking with IAA solution, accumulation of picfeltrarraenin IA showed a reverse trend relative to that for foliage spray, and stimulative effect of IAA reached the maximum level at 10 mg/L of IAA, accumulation of picfeltrarraenin IA dropped as IAA concentration increased. Both foliage spray and root soaking showed the strongest stimulative effect on accu-mulation of picfeltrarraenin IB at 50 mg/L of IAA. The effect of IAA on total picfeltrarraenins accumulation was similar to its effect on picfeltrarraenin IA, the stimulative effect reaching the highest level(i.e. the content of total picfeltrarraenins accu-mulation was at its peak) at 100 mg/L for foliage spray and at 50 mg/L for root soaking. Root soaking with IAA solution was better than foliage spray. ConclusionBoth MeJA and IAA can stimulate accumulation of picfeltrarraenins via foliage spray or root soaking. The best stimulative effect may be achieved when 20 mg/L of MeJA is used through foliage spray or 50 mg/L of IAA via root soaking.