Developmental Anatomy Of The Roots Of Four Herbs

Cotyledon node zone theory was established by professor Gu-An gen in 1990.According to the cotyledon node zone theory,seedling of dicots could be divided into three zones:epicotylary-shoot zone, cotyledon node zone(CNZ)and hypocotyl-root zone.And cotyledon node zone could be divided into three parts:upper,middle and lower.The roots of Achyranthes bidentata Bl.,Isatis tinctoria L.,Astragalus membranaceus(Fisch.)Bge.and Platycodon grandiflorum(Jacq.)A.DC.are the common nourishing herbal midicines in northeast of China. According to the cotyledon node zone theory,the developmental process of roots,the zonations of seedling and their locations of tap roots were studied by anatomical methods in order to produce high quality medical materials and provide theoretical basis for the microscopical judge of four herbs.Moreover the results provide the anatomical information of dynamic accumulation regularity of effective components and the accumulation sites of four herbs.The main results as follows:1.The CNZ type of the seedling of Achyranthes bidentata B1.is the telome elongation type.It has a haplostele in which the primary xylem is mesarch and diarch.It is the first time report that the morphology of the primary xylem is unequal double cruciform.The upper part of CNZ grew up the root crown.The middle and lower parts of CNZ grew up the root body.The lower of root came from the hypocotyl(CNZ-root transition region).The root stalk is not fatty.It has been found that both the primary and secondary structures of the root of Achyranthes bidentata resemble those of most of dicots.The root of Achyranthes bidentata is not fleshy.The thickening growth of the root principally results from the differentiation and development of the tertiary structure.2.The CNZ type of the seedling of Isatis tinctoria L.is the hemi-mesome elongation type.It has a haplostele in which the primary xylem is mesarch and diarch.The upper part of CNZ grew up the root crown. The middle and lower parts of CNZ and the hypocotyl(CNZ-root transition region)grew up the root body. The lower of the root stalk was part of the fleshy tap root.The root of Isatis tinctoria L.is fleshy.The thickening growth was due to secondary xylem in which there is a great lot of parenchyma cells.3.The CNZ type of the seedling of Astragalus membranaceus(Fisch.)Bge.is the telome elongation type.It has a haplostele in which the primary xylem is mesarch and triarch.The primary xylem is triarch was the first time found since CNZ theory was established.The CNZ grew up the root crown.The hypocotyl (CNZ-root transition region)grew up the root body.The root of Astragalus membranaceus(Fisch.)Bge.is not fleshy.The root grew thicken because the high degree of lignification of secondary xylem was abundant.4.The CNZ type of the seedling of Platycodon grandiflorum(Jacq.)A.DC.is the telome elongation type.It has a haplostele in which the primary xylem is exarch and.diarch.The CNZ grew up the root crown. The hypocotyls(CNZ-root transition region)grew up the root body.The root stalk is not fatty.The root of Platycodon grandiflorum(Jacq.)A.DC.is fleshy.The abundant secondary phloem results in the root thickening growth.5.Cotyledon node zone theory which was established by professor Gu-An gen in 1990 is authentic and impersonal.Moreover it has catholicity.