Daily dynamics of oligosaccharides, amylase and invertase activity in wheat lines isogenic for PPD genes under conditions of different photoperiod

Abstract

The paper presents the results of the study of the accumulation dependence and outflow of soluble carbohydrates and amylases and invertase activity on the state of PPD genes in leaves of isolines of winter wheat soft Triticum aestivum L. under the influence of different photoperiod durations. As plant material used monogenic dominant nearly isogenic by genes PPD (photoperiod) lines of winter wheat created in the genotype of Mironovskaya 808 variety: PPD-D1a, PPD-В1a, PPD-A1a and the variety, which is the carrier of exclusively recessive alleles of three genes ppd. Experiments were carried out in field and greenhouse conditions, the test plants were cultivating in contrasting photoperiodic conditions: 16 hours – a long day and 9:00 – a short day. The content, accumulation, outflow of oligosaccharides and the speed of these processes in plant leaves were determined by fixing the material during the photoperiodic cycle – “morning”, “evening”, and “morning of the next photoperiodic cycle”. The activity of the main enzymes of the carbohydrate metabolism of oligosaccharides – acid invertase and amylolytic complex was determined in the middle of the light period. According to the results of the experiments, it was found that under the conditions of a short photoperiod at the beginning and at the end of the light period, as well as at the end of the dark period (in the next photoperiodic cycle), the content of oligosaccharides in all the studied lines, regardless of their genotype in PPD genes, was lower than during these periods of the diurnal cycle under conditions of a long photoperiod. A short photoperiod caused a decrease in both the total accumulation of carbohydrates during the light period and their outflow during the night period for all the isolines and the variety, in comparison to the conditions of a long photoperiod. The outflow rate for all lines and the variety under the conditions of a short photoperiod was also lower than under the conditions of a long photoperiod and did not depend on their genotype for the PPD genes. It was shown that the PPD-B1a line, which proceeds to heading more slowly, is characterized by the maximum rate of oligosaccharide accumulation, but the minimum outflow rate. At the same time, the PPD-D1a and PPD-A1a lines, which switch to heading much faster than the PPD-B1a line, show the opposite regularities. It was revealed that under the influence of a short photoperiod in all studied lines and cultivar, regardless to the genotype for the PPD genes, the activity of amylases increased, compared with activity under the conditions of a long photoperiod, the activity of acid invertase changed differently. The highest level of invertase activity under conditions of a short photoperiod in the PPD-B1a line and cultivar coincides with the highest amylase activity and a more intense night outflow of oligosaccharides. The position is discussed that PPD genes or a certain combination of their state (dominant/recessive) may determine the development rate of the studied lines indirectly, in particular, through participation in the regulation of oligosaccharides metabolism.