Chemical stimulation of seed germination in Aconitum heterophyllum Wall. and A. balfourii Stapf.: important Himalayan species of medicinal value.

TLDR: The tetrazolium (Tz) staining pattern indicated that freshly collected seeds had high viability which decreased following storage at 4°C for 6 and 12 months and the combined treatments of gibberellin and cytokinin in general resulted in reduced ger mination in both species.

Abstract: Aconitum heterophyllum Wall, and A balfourii Stapf are important medicinal herbs of the Himalayan region The effect of plant growth substances (PGSs, namely, abscisic acid, 6-benzylaminopurine, gibberellic acid and zeatin riboside) and two nitrogenous compounds (thiourea and potassium nitrate) for enhancing and synchronising uniform germination was examined The tetrazolium (Tz) staining pattern indicated that freshly collected seeds had high viability which decreased following storage at 4°C for 6 and 12 months The treatments and time of seed germination were found to be significantly different (P <001) Gibberellic acid (GA 250 μM) significantly enhanced seed germination (425% compared to 275% in control) in A balfourii with in 15 weeks but was inhibitory in A heterohyllum, 6-Benzylaminopurine (BAP; 25 and 250 μM) and zeatin riboside (ZR; 25 and 250 μM) did not enhance germination in A balfourii; 250 μM ZR was actually inhibito ry In A hererophyllum the lower concentration of BAP was inhibitory (75% compared to 250% in control while 250 μM BAP enhanced germination (425% compared to 250% in control); the higher concentration of ZR was inhibitory The combined treatments of gibberellin and cytokinin in general resulted in reduced ger mination in both species Among the nitrogenous compounds, thiourea (CH 4 N 2 S) increased the rate and germination percentage in both species but potassium nitrate (KNO 3 ) enhanced germination in A baifourii only Seed germination was first detected in A balfourii in the 5th week (25%) Following treatment with 65 mM CH 4 N 2 S and this value increased to 225% in the 7th week and reached as high as 75% (compared to 275% in control) in the 15th week A higher dose of thiourea (130 mM) resulted in a rapid and high germination rate (40% compared to 0% in control) in the 7th week, reaching 75% in 10th and 12th weeks and a maximum 80% (compared to 275% in control) in the 15th week, In A heterophyllum, however, thiourea only marginally enhanced germination even up to the 15th week In A balfourii, KNO 3 (50 and 100 mM) significantly enhanced germination (62-70%) within 15 weeks