Abstract: A study has been made on the changes of ATP and protein content in cotyledons and apices of Pharbitis nil after flowering induction. Protein content of the cotyledons which have just got through the induction is 68% higher than that of the control, but the difference trends to disappear there after. The. difference of protein content between the induced and uninduced apices is not so obvious in the first three days after induction, but quite evident on the fourth day (30% higher in the induced apices) suggesting that there is some relationship between protein metabolism and flowering induction both in the cotyledons and in the apices. Just after the seedlings have been induced, ATP content of the cotyledons is getting much (134%) higher than that of the control and the tendency is retained towards the fourth day after induction. Generally ATP content in apices is one order of magnitude higher than that in cotyledons. Although ATP content in the apices is only slightly higher than that of the control soon after induction, it gains quite a lot in the second day until the fifth day the end of our experiment. In the third day after induction ATP level in the apices reaehs to the maximum (20.6×10-2 μmol/g, apices) which is 37% higher than that of the control. The results show that flowering induction is bound to be followed by increase of proteins and ATP both in apices and in cotyledoms. It also. shows both formation of the stimulus in induced cotyledons and evocation in the apices might be all concerned in expression of some genes and synthesis of new RNA and protein. According to the maximum peak of ATP in the apices and cotyledons appeared in 3rd to 4th day after induction, it seems that the inductive effect both in the cotyledons and apices might continue for some time under the following uninduced condition.

Key words: Pharbitis nil, Flowering induction, Level of ATP