The Impact of Seasonal Changes in Plant Tissue on Rhizogenesis of Stem Cuttings of Once Blooming Roses

Abstract

The majority of old and long-to-root roses are enough frost resistant to grow on their own roots in moderate and cool climates. The more often used method of rose propagation are single node stem cuttings derived from blooming shoots. The longtime of rhizogenesis causes extended influence of stress condition and precocious commissioning of ageing processes, which results a low rooting percentage. It was hypothesized that in the short season of flowering the amount of nutrients in shoots of stock plants changes, thus affecting the process of rhizogenesis, as well as condition of rooted cuttings, which may be estimated by the contents of biologically active components. The shoots of four cultivars were cut in four phenological stage: flower buds closed, flowers opened, just after petal shedding and 7-14 days after petal fall. The rooting percentage were counted after 10 weeks of rooting. The evaluation of plant material were carried out before and after rooting, including: soluble proteins, chlorophyll a and b, carotenoids, polyphenolic acids, reducing and total soluble carbohydrates. The SDS-page were performed before rooting. The rooting percentage were counted. The research revealed variability, characteristic for each examined cultivar, in the content of biologically active compounds, both before and after rooting, in cuttings harvested from stock plants in successive phases of development. Decrease in pigment contents in leaves of rooted cuttings may suggest a progressing senescence, both during propagation and later in a vegetative season. The cuttings of 'Mousseuse Rouge' rooted similarly when harvested in each of the phenological phases (53.8-67.5%). For other cultivars the highest rooting percentage was obtained for cuttings harvested from shoots with closed flower buds (‘Hurdals’ 47.5%, ‘Maiden’s Blush’ 55.0%, ‘Semiplena’ 67.5%). In these cultivars a relationship between rooting percentage and changes in the content of pigments, sugars or/and polyphenolic acids in successive phase was shown.

Keywords

• maturity of shoots
• stem cuttings
• old roses
• stock plant