Some physiological changes occurring at early stage of floral bud differentiation in cucumber cotyledons cultured in vitro were studied.The results are as follows.The contents of mineral elements appeared to change variously,for example the contents of Cu and Fe greatly increased on the 2nd day of culture,Zn also increased on the 4th day,but Ca quickly decreased on the 6th day.The activity of peroxidase was increasing but the levels of ...