Comparison of the development of taproots between 'Tai-tsai' and 'pakchoi'

'Tai-tsai' is a variety of pakchoi. The main root of pakchoi does not expand during the whole growth period, but the main root of 'Tai-tsai' will be thickened obviously, showing an inverted-cone shape. The purpose of this study was to explore the reasons for the expansion of the fleshy roots during the root development in 'Tai-tsai'.