Correlations between delayed fluorescence of chlorophyll, metabolism and yield of plants. II. Influence of moisture of leaf and temperature condition on delayed fluorescence of leaves

Abstract

During various temperatures of incubation the dehydration of leaves up to 3.2-3.8% mainly induced increase maximum amplitude of delayed fluorescence of chlorophyll. It was shown that moisture loss with this range could be determined for the most part by the growth of the electrochemical potential of thylakoid membranes. The further incubation of detached leaves at 36℃ temperature, with more notable moisture loss, resulted in specific its decline as opposed to cases of 22 and 6℃ of thermal incubation. It was confirmed that the increased temperatures and moisture loss damage of the cells of plants occurred together induce a greater influence on plants than in case of occurring apart. The results allow to suppose that this can be mostly caused weakly associated polypeptides fallen out from the chloroplast membrane, which may be stipulated by high temperature combined with change ionic and osmotic stresses due moisture loss. Simultaneously, the results showed that the exposure of the critical lowered air temperature led to considerable typical changes of leaves delayed fluorescence parameters of field plants. Therefore, their use can constitute new approaches to elucidate the molecular basis of plant freezing tolerance in a timely manner, based on concentration-related changes and the efficiency of coupling between light and dark processes of plants.

Correlations between delayed fluorescence of chlorophyll, metabolism and yield of plants. III. Influence of viral infection on field plants and new technology of clone selection of virus-free planting potato

“…The decay of induction curve was generally explained by a decrease in the membrane energization as a result of secondary cation efflux from thylakoids [11,12]. Our results showed that half time of I decay-τ describe the level of interaction LR and DR of plants [13,14].This is a biological base triggering the use of these DF parameters in physiological research. The interest of using the parameters of this luminescence for the diagnosis of plants' state is identified also by the possibility of their fast measurements on intact objects by the use of comparatively simple and accessible equipment.…”

“…Under continuous influence of virus infection, changes in the DF parameters were observed analogously, caused by water stress on potato, modified by doses of phosphorus fertilizers [13], leaf prolonged dehydration and frosts influence [14], which also being correlated with the changes of yield. Therefore, these results allow recommend the use of DF parameters in the systems analysis of production process.…”

“…During the experiment, the interaction between the key LR and DR centers may induce I and τ changes [13,14]. The elimination of τ values influences could eliminate the DR affect on I [13,14].…”

“…During the experiment, the interaction between the key LR and DR centers may induce I and τ changes [13,14]. The elimination of τ values influences could eliminate the DR affect on I [13,14]. During the experiment, the accumulation of changes in active PSII concentration in the end of the vegetation period was indicated by the reduced ratio of I A /I B (r IA/IB T = -0.989), the correspondence of which was significant in case of eliminating the effect of the degree of interaction between LR and DR (r IA/IB T (τA/τB) = -1.000) ( Table 1).…”

“…DF induction curve, registered in a several minutes time period, encompasses two major phases-a fast one, taking place in the first second of induction, and a slow one, that can last for minutes (Figure 1). Each phase is shaped by several processes running at the same time [11,12].When applying the phosphoroscope-based method of registration, the maximum intensity of leaf DF curve (I, fast phase), the phases of which many authors attribute to the changes of the electrical potential, depending on the size of ECP on a membrane on the state of the PSII reaction center, since the light induced potential difference and the proton gradient across the thylakoid membrane are thought to reduce the amount of activation energy necessary for the back reaction between QAand Z + to occur and on the other hand, the I level follows the extent of the variable component of fluorescence and has been suggested to be proportional to the amount of oxidized QA at the beginning of illumination [10][11][12], as well as the concentration of active centers of the PSII [13,14]. Previously, it was assumed that the time course of DF after the maximum is possibly influenced by a number of DR (directly or indirectly modifying the characteristics of PSII) [11,12].…”