Energy and Matter Changes in Maize Plants Influenced by 24-epibrassinolide

Abstract

Brassinosteroids are known to affect sourcesink relationships in plants, possibly by affecting auxin redistribution in plants, which has an indirect effect on the metabolism of carbohydrates, and thus on growth and development of plants. Since source-sink relationship are main determinante of crop yield, the need for a more precise characterization of the effect of brassinosteroids is very important. One of the methods of the studyng the issue is thermodinamic, i.e. expression of plant growth and development through quantitatively verifiable energetic parameters (enthalpy, entropy, Gibbs free energy), i.e. mostly qualitative growth parameters. We tested this approach at three levels of maize development: a) seedlings; b) adult individual plants; c) adult plants in the field. Since the methods for determining thermodynamic parameters are destructive, the proposed approach was whole implemented only at the level of seedlings, partly at the level of individual adult plants, while the determination of thermodynamic parameters at the field level was not implemented. In addition to other measurements, a regression comparison of the mentioned thermodynamic parameters and the concentration of important sugars was performed in different corn seedling parts. The results indicate that the germination and initial seedling growth influenced by the flow of sugars from remaining seed (as source organ) towards plumule and radicle (as sink organs). Also, alterations in Gibbs free energy play a significant role in these sugar transfer within maize seedlings. In the context of the obtained findings in corn seedlings, the result of the experiments conducted at individual adult maize plants and corn plants in the field are disscused.