Endogenous hormone content in relation to thickening of carrot fleshy root during summer season in plateau region Exogenous GA3 influence on the development of summer cultivated carrot fleshy root on plateau Distributions of endogenous hormones relative to formation of cracked and malformed fleshy roots of carrots Endogenous Hormone Content of Fleshy Root in Relation to Early Bolting in Summer Cultivated Carrot on Plateau