Polyvariance of Shoot Morphogenesis in Clones of Salix triandra (Salicaceae) Against the Background of the Periodicity of Rainstorms

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.

Obtaining calli and regenerated plants in anther cultures of pea

Pea (Pisum sativum L.) is a species for which there is no efficient method for the recovery of haploid plants yet. This research investigated the influence of various genotypes, nutrient media, and stress treatments on callus formation, embryogenesis and plant regeneration in anther cultures of pea. A wide range of pea genotypes and nutrient media was studied. Morphogenic calli were initiated on media supplemented with α-naphthaleneacetic acid (NAA), 6-benzyladenine (BA), and 2,4-dichlorophenoxyacetic acid (2,4-D) without application of stress treatments. Embryogenic calli and embryos were regenerated on media with low sucrose content in the presence of 2,4-D or indole-3-butyric acid (IBA) after cold stress (4°C) of isolated buds, alone or in combination with in vitro treatment of isolated anthers at higher temperatures (35–38°C). The efficiency of regeneration via shoot morphogenesis on different nutrient media and the peculiarities of regeneration from embryogenic calli were investigated. Green embryogenic calli initiated on 2,4-D were able to develop through shoot morphogenesis on a medium supplemented with BA and NAA. This process led to regeneration of hypertrophic embryos at various developmental stages. The origin of regenerated plants (i.e. from microspores or somatic anther cells) was estimated using marker alleles determining morphological traits. Almost all R₀ regenerants derived from morphogenic calli originated from anther somatic cells.