[Levels of hydroxycinnamic acids and free auxins in tobacco during photoperiodic induction].

The photoperiod controls hydroxycinnamic acids (involved in light signal transmission via interaction with the control proteins) in addition to plant hormones in tobaccos of different biotypes during the vegetative-to-reproductive switch of the genetic program. Hydroxycinnamic acids content shows a regular time pattern during the transition to flowering: the level of cinnamic acid decreases while the level of ferulic and chlorogenic acids increases despite the opposite photoperiodic response of the two tobaccos. Considering the possible use of hydroxycinnamic acids in light energy transduction, one can propose involving these substances in the reactions that induce plant flowering.

Ultrastructure of Chenopodium rubrum L. apices during the effect of fusicoccin and photoperiodic induction.

Plant transition from vegetative to reproductive development is associated with ultrastructural changes in stem apices. Those seen in Chenopodium rubrum L. under the influence of fusicoccin in many ways resemble those induced by a short-day treatment favourable to flowering.

Floral and growth responses in Chenopodium rubrum L. to an extract from flowering Nicotiana tabacum L.

Flowering of Chenopodium rubrum seedling plants was obtained in continuous light after application of fractions of a partially purified extract from leaves of flowering Maryland Mammoth tobacco (Nicotiana tabacum). The stage of flowal differentiation was dependent on the age of the Chenopodium plants used for the bioassay. Apices of plants treated with the extract at the age of four or seven days showed an advanced branching of the meristem or the beginning of formation of a terminal flower; treatment with the extract of plants 12 d old resulted in rapid formation of flower buds in all assay plants.

Growth, activity of phytohormones and inhibitors, and photosynthesis of dwarf pea mutants under different conditions of illumination.

A clear correlation was found between the growth of mutant forms of pea plants and the light intensity: With an increase in the latter the growth of the plants was inhibited and the rate of photosynthesis increased. The inhibitory action of light on stem growth affected not only tall pea plants, but also dwarf forms. A definite link was observed between the genetic apparatus and the balance of endogenous phytohormones and inhibitors.