The Effects Of Exogenous Substances On The Vernalization Of Broccoli

Broccoli (Brassica oleracea L. Var. Italica Planch.) which is a green plant vernalization in developmental process, can't gain production organ of floweball with the inducement of low temperature, until the plant grows big enough. Nowadays how to control vernalization becomes the priority study in broccoli culture. The experiments took prematurity broccoli hybrid named 'Qing-feng 103' and medmaturity broccoli hybrid named 'Lv-xiu' as the objects to study the effects of exogenous substances on the vernalization and development of broccoli by spraying or root fertilizing of kinetin, gibberellin and 5-azaC. The results show that:Exogenous substances treatments could observably shorten the vernalization and flower bud differentiation stage, as well as the flowerball developmental stage. Effects of kinetin treatments were better than effects of 6-BA treatments under the same processing, and effects of kinetin root fertilizing treatments were better than effects of kinetin spraying treatment, moreover, effect of 80 m·L^-1 of kinetin spraying treatment was more better than others in our study, and 0.4 mg·L^-1 of kinetin root fertilizing treatment was best; Gibberellin spraying treatment could promote the vernalization of broccoli, and 50 mg·L^-1 of gibberellin spraying treatment could shorten flower-bud differentiation stage, increase the yield and tight degree best. However, 100 mg·L^-1 gibberellin spraying treatment reduced the yield of broccoli; Effects of lower concentration of 5-azaC were better than higher ones, and the treatment of 10 mg·L^-1 of 5-azaC spraying was the shortest one in promoting flower-bud differentiation stage. Whereas, 5-azaC could observably reduce the yield, tight degree and quality, and the higher concentration of 5-azaC was, the worse effect of it did. And the yield, tight degree and quality of 5-azaC root fertilizing treatments were lower than spraying one.During vernalization, carbohydrate content increased, nitrogen compound content decreased. Moreover, when the broccoli entered critical stage of flower bud differention, soluble sugar, sucrose, reducing sugar, soluble protein content increased sharply, as well as the ratio of total sugar to total nitrogen, soluble sugar to total nitrogen, sucrose to total nitrogen, reducing sugar to total nitrogen, however, starch and total nitrogen content decreased sharply,Soluble sugar, sucrose, reducing sugar, soluble protein content and C/N in broccoli which was treated by kinetin, gibberellin or 5-azaC were bigger than the one without kinetin, gibberellin and 5-azaC treating. Also, the time when C/N begined to increase sharply was later than the time when the broccoli entered into critical stage of flower bud differention.In our study, higher content of soluble sugar, sucrose, reducing sugar, soluble protein and lower content of starch, total nitrogen were needed in both prematurity broccoli hybrid and medmaturity broccoli hybrid. However, medmaturity broccoli hybrid needed more time to start venalization.