The hormonal and genetic effects induced by an irradiation in small dozes at Tradescantia (a clone 02)

The purpose of the present work was studying the possible interrelation of the hormonal status of plants and size of the genetic effects induced by an irradiation in small dozes. The frequency of somatic mutations in strings Tradescantia (a clone 02) at an irradiation in dozes up to 28 cGy was estimated. Influence radiations in a range from background up to 28 cGy on the maintenance in inflorescences Tradescantia (a clone 02) the basic groups of plant hormones is investigated: abscisic acid, cytokinin, auxin and gibberellin A3. It is shown, that small dozes of an irradiation cause extremely radical changes of hormonal balance in fabrics of inflorescences Tradescantia. Received results are discussed with attraction of the data on influence phytohormones on kinetics a cellular cycle.     

The role of hormonal balance in plant adaptation to flooding

The effect of flooding on the growth parameters and hormonal dynamics (anxins, abscisic acid, cytokinins, gibberellins, and ethylene) has been studied in a vegetation experiment on the leaves of wheat (Triticum aestivum L.) and oat (Avena sativa L.). Growth inhibition during flooding in both species was due to the accumulation of abscisic acid and ethylene, while the repair processes were due to the increased level of auxins, cytokinins, and gibberellins. The difference in the hormonal response in wheat and oat to flooding, in particular, the degree and timing of accumulation of abscisic and indoleacetic acids and different dynamics of the level of cytokinins and gibberellins, induced their different physiological response, which determined the level of their resistance. The growth control of cereals during flooding as well as the hormonal dynamics are proposed to rely on the strategy of plant ontogenetic adaptation.     

Gametophyte–Sporophyte Interactions in the Pollen–Pistil System: 3. Hormonal Status at the Progamic Phase of Fertilization

The content of hormones, IAA, ABA, and cytokinins, as well as the rate of ethylene production in petunia (Petunia hybrida L.) pistils and their parts (stigma, style, and ovary) were determined over 8 h after compatible pollination. At the progamic phase of fertilization in the pollen–pistil system, the phytohormones were virtually absent from the ovary but were present in various proportions in stigma and style. The stigma was the main site of ethylene synthesis and contained 90% of ABA while the style contained 80% of cytokinins of their contents in the whole pollinated pistil. Stigma and style did not differ in their IAA levels. The interaction of the male gametophyte with the stigmatic tissues was accompanied by a threefold increase in the ethylene production and a 1.5-fold increase in the IAA content in the pollen–pistil system within 0–4 h. Growth of pollen tubes in the stylar tissues (4–8 h) was accompanied by a further increase in IAA content and a decrease in the ethylene production by stigmatic tissues, as well as by a decrease in the cytokinin content in the stylar tissues. The ethylene/auxin status of the stigma may be suggested to control the processes of adhesion, hydration, and germination of pollen grains during pollination, while the auxin/cytokinin status of the style controls the pollen tube growth.