The impact of the structural state of the tubulin cytoskeleton on chlorophyll fluorescence indicators and auxin content in Solanum tuberosum

Abstract

Background. Information on the dependence of light reactions of photosynthesis on the structural state of cytoskeletal elements is extremely limited. It is known that the cytoskeleton with membranes forms a cytoskeleton-membrane complex, the disruption of which should affect the course of membrane processes that are under hormonal control. It is of interest to study the effect of antioxidants on physiological processes under conditions of cytoskeleton destruction. Among antioxidants, researchers pay special attention to phenolic compounds. However, there is no information in the literature about their effect on chlorophyll fluorescence under conditions of microtubule destruction. The purpose of the work was to study the initial and maximum fluorescenceof chlorophyll, non-photochemical quenching of fluorescence and quantum efficiency of PS II, as well as the auxin content in Solanum tuberosum plants with an intact and oryzalin-destructed tubulin cytoskeleton. At the same time, the effect of the antioxidant caffeic acid on chlorophyll fluorescence during the destruction of microtubules was studied. Materials and methods. The object of the study was potato plants (Solanum tuberosum L.) variety Zhukovsky early, grown in soil culture. Destruction of the tubulin cytoskeleton was carried out 15 days after emergence by spraying the plants with a 15 μM oryzalin solution. Caffeic acid at a concentration of 0.1 mM was sprayed on plants after treatment with oryzalin. Registration of leaf chlorophyll fluorescence in intact plants was carried out using a MINI-PAM portable fluorimeter. Before measurements, the leaves were dark adapted. Auxin content was determined by enzyme-linked immunosorbent assay. Indolylacetic acid (IAA) was taken as a standard solution. Mathematical data processing was carried out using the CXSTAT application to the Excel computer program. Results. Studies have revealed a 22 % increase in energy losses in the antenna and from the antenna to the PSII reaction center (F0) under the influence of oryzalin, as well as a 1.5-fold increase in photochemical fluorescence quenching (NPQ). In this case, a 20 % decrease in the reduction of plastoquinone in the reaction center of PS II (Fm) and a 40 % decrease in the potential quantum efficiency (Fv/Fm) were detected. A decrease in IAA content (almost 3 times) was shown during pharmacological destruction of microtubules by oryzalin. Caffeic acid reduced the negative effect of oryzalin on chlorophyll fluorescence and auxin content. Disruption of the structural state of microtubules reduced the initiation of tuberization and the productivity of potato plants. Caffeic acid removed this effect of oryzalin. Conclusions. The dependence of Solanum tuberosum chlorophyll fluorescence indicators on the structural state of the tubulin cytoskeleton was revealed against the background of changes in the content of phytohormones auxins. The protective effect of the antioxidant caffeic acid on the functioning of the photosynthetic apparatus in plants with a disturbed tubulin cytoskeleton against the background of changes in auxin content has been shown. let-membrane continuum, and with the content of auxins.

Keywords

• tubulin cytoskeleton
• oryzalin
• chlorophyll fluorescence
• auxins
• caffeic acid