Frequency

  of frequency distributions of root traits under different culture patterns and stages. a, IHC; b, OHC; c, SS; d, RDW TRL, total root length; TRV, total root volume; NRT, number of root tips; TRA, total root area; ARD, average root diameter; RDW, root dry weight; IHC, indoor hydroponic culture; OHC, outdoor hydroponic culture; OPC, outdoor pot culture; SS, seedling stage; WP, wintering period; JS, jointing stage; MS, mature stage.