The dissertation work is devoted to find out the patterns of growth and assimilation processes, the phytohormonal status of soybean isogenic by E genes lines (Glycine max (L.) Merr) cv. Clark under different photoperiod influence. The effects of individual E genes (E1/e1, E2/e2, E3/e3) on the development rate, the intensity of growth and assimilation processes, the content, activity and ratio of phytohormones (IAA, GA and ABA) in the leaves and the stems apical meristems (SAM) of soybean isolines have been studied under different photoperiodic conditions.
The aim of the study was to find out the effect of the photoperiod duration on the growth, development, morphogenesis, activity, content and balance of phytohormones in the leaves and stems apical meristems in isogenic by E genes soybean lines. The following tasks were to establish the effect of different photoperiod duration on the rate of transition to flowering of isogenic lines, the dynamics of morphophysiological processes in isolines, the content, activity and balance of phytohormones in leaves and stems apical meristems of isolines; to find out the connection between phytohormonal balance and the allelic state of E genes of isogenic soybean lines at different photoperiods.
All experiments used isogenic by E genes lines of soybean (Glycine max (L.) Merr), created in the genotype of cv. Clark short day (genotypes E1E2E3, E1e2e3) and day neutral (genotypes e1E2e3, e1e2E3, e1e2E3).
Phenological observations have shown the dependence of the development rate on the allelic state of the E genes (E1 / e1, E2 / e2, E3 / e3) in the genotype of soybean isolines at different photoperiodic conditions. Thus, in a long photoperiod, the difference in the duration of the vegetative phase (Ve R2) between isogenic lines was manifested. Under these conditions, lines with dominant alleles of E genes in the genotype (one or all three) have been flowering later than lines with recessive alleles of these genes. The latest flowering occurred in the lines E1e2e3 and E1E2E3, which have E1 gene in the genotype. That is, the effects of E genes on the rate of soybean development were phenotypically manifested in a long day.
Morphophysiological studies of the intensity of growth processes, the formation of biomass and the dynamics of assimilation indices have shown the dependence of the intensity of these processes on the photoperiod duration and the allelic state of E genes in the genotype of isolines. During the experiment, these indicators increased in all lines, regardless of the photoperiod duration and their genotype by E genes. However, in the short photoperiod, the increase in the main stem height and the number of leaves, as well as the accumulation of dry mass was much smaller than in the long photoperiod. During the studied ontogenetic period (two weeks) in all isolines, regardless of the genotype by E genes and the duration of the photoperiod, the assimilation processes increased. The RGR and NAR under the short day decreased in the first week and then increased in the second week of the experiment. The degree of change in the indices varied depending on the isoline genotype by E genes. The LAR and LWR were lower under the short day in SD lines. These indices were the same in the ND lines under short and long day. Under the short photoperiod the SLA in SD lines was higher, and in ND lines it was practically the same for both photoperiods.
For the first time, differences in the effect of long (16 hour) and short (9 hours) photoperiod on the content, activity and ratio of phytohormones (IAA, GA and ABA) in the leaves and the stem apical meristems (SAM) of soybean isolines have been detected. This helped to clarify the changes in the balance between phytohormone accumulation, outflow and / or hydrolysis under the influence of different photoperiod durations. It was shown that the effects of both long and short photoperiods depended on the state of E genes (E1/e1, E2/e2, E3/e3) in the genotype, which indicates the relationship between genetic and phytohormonal control of soybean development. The modifying effect of the short photoperiod on the E genes effects on the content of IAA, GA and ABA, as well as their balance in the leaves and SAM of soybean isolines has been established. A new thesis has been formulated about the possible realization of the E genes effects on the soybean growth and development through interaction with the hormonal system through influence on the phytohormonal status of plants. The results of the study can be the basis for the development of new methods and agricultural techniques for regulating the rate of soybean development.
Key words: soybean (Glycine max (L.) Merr), long and short photoperiod, E genes, growth, the development rate, phytohormonal status, IAA, ABA, GA.
