Effects of growth regulators and growth media on root-hair development of Poncirus trifoliate

By using river sand and mixed soil as growth media,and treating with different concentration IBA,ETH,and NAA,this paper studied the root-hair development of Poncirus trifoliate seedlings,and the development cycle and distribution pattern of the root-hairs under phosphorus deficiency in sand culture.The root-hairs had a development cycle of about 4 days,and formed block-shaped and clumped,mainly around root,and with uneven distribution.Sand culture gave rise to the production of more root hairs,with an average of 486.3 per tap root,and treating with 1.0 μmol·L-1 of IBA and ETH notably promoted root-hair development.The phosphorous deficiency in sand culture induced more root hair formation(636.3 per tap root).Mixed soil culture produced lesser root-hairs(212.3 per tap root),and all the test growth regulators had no obvious effects on the root-hair development.