Changes in water content in ripening fruits of sea buckthorn (Hippophae rhamnoides L.)

The dynamics of changes in the degree of hydration of fruit pulp (hypanthia) and seeds of 2 varieties (Duet, Vasilisa) and 2 hybrid forms (T-50, 8/93) of sea buckthorn bred by V.A. Fefelov in the conditions of the Nizhny Novgorod region are studied. It was found that at the early stages of fetal ontogenesis (62nd day after pollination (DAP)), the humidity levels of each of these organs were commensurate and reached 85–88 and 78–82%, respectively. In the process of fruit maturation, the dynamics of these processes acquired a different orientation, which consisted in reducing the degree of seed hydration against the background of practically constant hydration of the fruit pulp. Differences in the rate of change in the moisture content of the tissues of these organs determined the level of their hydration. By the time the botanical maturity fruits of (109 DAP) was reached, the water availability of each of the varieties and forms was maximum (Duet variety – 88.6, T-50 – 91.6%, with Vasilisa variety and form 8/93 values were within these limits). By the time the fruits reached technical maturity (the period from 135 to 144 DAP), the hydration of tissues of all varieties and shapes decreased by 1–2%. In seeds, unlike fruit pulp, the moisture content of tissues decreased throughout the entire period of fetal ontogenesis. There were 3 stages in changing of the speed of this process: the first of them occurred in the period from 62 to 87 DAP, was accompanied by the formation of seed tissues, hard seed coats and their browning, the second – from 87 to 135 DAP (the phase of botanical maturity) – was characterized by an almost unchanged level of hydration. The third stage of dehydration was observed from 135 to 144 DAP. During this period, the rate of decrease in the moisture content of seed tissues increased by 1.5 times (from 2.47 to 3.74%/day). Some individual varietal features of the quantitative water content in the tissues of seeds by 144 DAP were registered: Duet variety – 28.6, Vasilisa – 25.6, T-50 – 22.6%, form 8/93 exceeded all others and reached 32.5%. The hydration of the fruit pulp of hypanthium remained practically unchanged throughout the entire period of fruit ripening and amounted to 88.6–91.6%.