Polyvariance of Shoot Morphogenesis in Clones of Salix triandra (Salicaceae) Against the Background of the Periodicity of Rainstorms | Поливариантность морфогенеза побегов в клонах Salix triandra (Salicaceae) на фоне периодичности ливневых осадков

The article substantiates the need to study the development of one-year saplings from cuttings of almond willow (Salix triandra). Purpose of research: identification and analysis of seasonal dynamics of daily growth of shoots in S. triandra clones against the background of excessive atmospheric moisture in the form of three showers in 2020. Material and methods. Research methods: selection, structural-morphological, chronobiological. Object of research: model inbred-clone one-year population of S. triandra. The number of clones is 7; the recurrence is 6-fold. Material: growing annual shoots on one-year saplings; each sapling was formed into a single shoot. Results. Under experimental conditions, the rooting capacity of cuttings was 100%. Dimorphic root systems were formed on the mother cuttings of the excavated seedlings. The annual growth of the strongest shoots was 175 ... 215 cm. The daily growth in shoots reached peak values by June 10: the average daily growth was 3.6 cm/day, the maximum — 4.4 ... 4.9 cm/day. After June 10, the daily growth rate decreased unevenly until the end of the growing season. Some shoots completed growth before the beginning of August, and some continued growth until the middle of August. The cyclical nature of the seasonal dynamics of daily growth in the form of three peaks separated by two dips is established. The third peak is formed after the third rainstorm. Discussion and conclusions. Cyclical seasonal dynamics of daily growth of shoots is characterized by a high degree of synchronization of growth processes. Probably, all the shoots are affected by some powerful pulse synchronizer of unknown nature. It is possible that periodic showers may have a modifying effect on the mechanisms that regulate growth processes. The temporal discreteness of shoot morphogenesis is due to the full or partial realization of the seasonal cycle of shoot development. The duration of growth is due to interclonal and intraclonal differences. Probably, the duration of morphogenesis is controlled by both genetic and epigenetic factors.