Be aware that shake-proof nuts will appear to stop once the bolt reaches the little plastic inserts in the top. If you have got that far you'll be fine, just keep going. The initial specific growth rate of Atropa belladonna hairy roots in shake flasks was found to vary with the number of inoculum root tips. Increasing the number of . growth approximately threefold higher than in shake flasks . roots from shear stress, although Azadirachta indica hairy roots were still unable to produce .