In Vitro Induction and Primary Evaluation of Octoploid Plants in Saskatoon Berry (<i>Amelanchier alnifolia</i> Nutt.)

Polyploids of many species of horticultural plants are widely used in breeding programs since they are characterized by vigorous growth, larger organs, and greater resistance to biotic and abiotic stress. Saskatoon berry (Amelanchier alnifolia Nutt.) is in a form of diploid (2n = 2x = 34) and tetraploid. So far, no reports on induction of polyploidy in this species have been found. The aim of the study was to obtain Saskatoon berry octoploids with the use of in vitro shoot cultures. Shoots of the tetraploid of Canadian cultivars ‘Martin’ and ‘Smoky’ derived from in vitro cultures were used for induction of chromosome doubling. The shoot explants were incubated in a multiplication medium with the addition of one of the following antimitotics: colchicine, trifluralin, oryzalin or amiprophos methyl (APM) for two weeks (six days in the darkness and then eight days under a 16-h photoperiod). Then, the shoots were transferred to the multiplication medium without antimitotics and propagated in vitro by two subcultures. Octoploids were selected based on flow cytometry. Trifluralin showed the most phytotoxic effect. Six octoploids were obtained, four for ‘Martin’ after treatment with 250 mg L−1 of colchicine and two for ‘Smoky’ following the treatment with 5 mg L−1 of APM. All obtained octoploid individuals were multiplied and the level of ploidy was re-examined by flow cytometry and chromosome counting, which confirmed their octoploid genotype (2n = 8x = 136). They are probably the first octoploids of the genus Amelanchier in the world. The newly obtained octoploids were rooted in vitro, acclimatized to ex vitro conditions and grown in a greenhouse. Octoploids grew very slowly and showed a tendency to premature dormancy, which was manifested by inhibition of growth. In octoploid plants, the stomata were significantly larger and the number of stomata per 1 mm2 of leaf area was lower, compared to the tetraploid counterparts

Exposure to Light of the Abaxial versus Adaxial Side of Detached <i>Kalanchoë blossfeldiana</i> Leaves Affects Anthocyanin Content and Composition Differently

The accumulation and composition of anthocyanins in leaves of Kalanchoë blossfeldiana, detached and kept for five days under natural light conditions, were investigated. The presence of fifteen derivatives of cyanidin, petunidin, and delphinidin was found. Changes in the content of each anthocyanin in the leaves before and after exposure to light on the abaxial (naturally upper) and adaxial (naturally lower) sides of the leaves were compared. When the adaxial side was exposed to light, the anthocyanin contents of the leaves did not change. In contrast, when the abaxial side of detached leaves was exposed to light, there was enhanced accumulation of delphinidin-rhamnoside-glucoside, cyanidin-rhamnoside-glucoside, cyanidin-glucoside-glucoside, and two unknown derivatives of petunidin and delphinidin. Application of methyl jasmonate (JA-Me) on the abaxial side exposed to light inhibited the accumulation of these anthocyanins. This effect could probably be due to the presence of these anthocyanins in the epidermal cells of K. blossfeldiana leaves and was visible in the microscopic view of its cross-section. These anthocyanins were directly exposed to JA-Me, leading to inhibition of their formation and/or accumulation. The lack of significant effects of JA-Me on anthocyanin mono- and tri-glycosides may indicate that they are mainly present in the mesophyll tissue of the leaf

Accumulation of Anthocyanins in Detached Leaves of <i>Kalanchoë blossfeldiana</i>: Relevance to the Effect of Methyl Jasmonate on This Process

Accumulation of anthocyanins in detached leaves and in excised stems of Kalanchoë blossfeldiana kept under natural light conditions in the presence or absence of methyl jasmonate (JA-Me) was investigated. When the abaxial surface of detached leaves was held lower than the adaxial surface (the normal or natural position) under natural light conditions, anthocyanins were not accumulated on the abaxial side of the leaves. In contrast, when the adaxial surface of detached leaves was held lower than the abaxial surface (inverted position), anthocyanins were highly accumulated on the abaxial side of the leaves. These phenomena were independent of the growth stage of K. blossfeldiana as well as photoperiod. Application of JA-Me in lanolin paste significantly inhibited anthocyanin accumulation induced on the abaxial side of detached leaves held in an inverted position in a dose-dependent manner. Anthocyanin accumulation in the excised stem in response to natural light was also significantly inhibited by JA-Me in lanolin paste. Possible mechanisms of anthocyanin accumulation on the abaxial side of detached K. blossfeldiana leaves held in an inverted position under natural light conditions and the inhibitory effect of JA-Me on this process are described. The accompanying changes in the content of primary metabolites and histological analyses were also described