The fleshy root is a fleshy metamorphic organ formed by the expansion of the taproot and consists of three parts: the head, the neck and the true root. The head develops from the epiblast and is a short, condensed stem with dense buds and leaves. The true root develops from the radicle and bears two or four rows of lateral roots. The neck develops from the hypocotyl and is devoid of leaves and lateral roots.
The different fleshy roots can be categorized as turnip-type, carrot-type and beet-type. Radish-type fleshy roots are formed by triple thickening, together with splitting of thin-walled tissues in the secondary essential part; carrot-type mainly depends on the secondary growth of the vascular bundle formation layer, there is no activity of the secondary formation layer with triple thickening, and the number of cells and thickness of the phloem varies greatly; beet-type is a concentric arrangement of formation layers derived from the mesocarpal sheaths and the phloem, with each formation layer dividing inwardly into the secondary xylem, and outwardly into the secondary phloem to compose the vascular bundle ring. Vascular ring.
The temperature suitable for taproot expansion varies depending on the type of vegetable and ecotype, 17-20 ℃ for fall radish, spring radish 21-23 ℃, the ground temperature is higher than the air temperature, to 21-23 ℃ is appropriate. Sufficient sunshine is conducive to the expansion of fleshy roots, autumn and winter radish is suitable for the first long sunshine, root expansion period of short sunshine, spring radish is suitable for the first short sunshine, late sunshine long. Soil layer deep, well-drained, aeration, water retention of strong sandy loam, favorable to the fleshy root hypertrophy.