Synthesis shoot meristems

The administration of antimetabolities of transcription and translation inhibits the induction of flowering in plants that are dependent on the length of day just as it does in those requiring vernalization. The inhibitors produce their effect partly in the leaf, partly in the shoot meristem. As far as their activity in the leaf is concerned, it may be assumed that they impair the activity of the genes that are involved in the synthesis of the flowering hormone. At least in part their effectiveness in the shoot meristem has to do with subsequent flower differentiation rather than with flower induction the activity of the genes for flower differentiation is interferred with. 

Solanaceae such as tomato and vice-versa provide evidence that the roots are the site of alkaloid biosynthesis in these plants. Histochemi-cal techniques utilising alkaloid precipitants coupled with microscopic examination of treated tissues have located accumulations of positively reacting materials in the meristems of both the roots and shoots of belladonna. These observations do not, however, unequivocally implicate the meristems in the initial synthesis of the alkaloids and experiments using tissue culture techniques have demonstrated that there is no simple relationship between cell division and alkaloid synthesis. Rapidly dividing cultures of belladonna cells do not synthesise alkaloids—only when root initials are induced to form does alkaloid biosynthesis commence. Thus the importance of roots in the synthesis is confirmed although the site of synthesis within these organs has not yet been rigidly established. 

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