Phytohormone changes during storage root growth in Beta species

Abstract

The physiological and morphological factors necessary for efficient accumulation of sucrose in sugar beet (Beta vulgaris L.) are considered in relation to potential uses of plant growth regulators to modify the anatomy of storage roots so as to increase sucrose content and yield . The percentage of sucrose in root fresh and dry matter is closely related to root structure . Sugar beet, mangold and chard are three sub-species of Beta vulgaris that differ considerably in their anatomy, assimilate partitioning, sucrose concentration and root dry matter yield . The concentrations of indole-3-acetic acid (IAA), abscisic acid (ABA) and cytokinins were measured during the growth of the storage root in each of these cultivars . Correlations were found between the phytohormone levels and the formation of secondary cambia and their subsequent cell division and expansion activity .

Sugar Accumulation in L19 Type Sugarbeet Germplasm

“…The rapid rate of sucrose accumulation after HI may be due to a higher cell division rate (Doney andTheurer, 1983, 1985) or to a different root development pattern for L19. Hosford et al (1984) found that three subspecies of Beta vulgaris differ consid erably in their seasonal development. Sugarbeet had continual cell division and expansion throughout the growing season, chard showed little or no cell expansion, while root growth in mangolds was essentially expansion of the parenchyma cells in the first 4 rings.…”

“…Ultimately, the controlling factors in L19 may be hormones or growth regulators that dictate when cell division and cell expansion occurs and the rate at which it proceeds, or they may be due to cell membrane transport kinetics. Hosford et al (1984), Saftner and Wyse (1984), and Saftner (1986) have observed that hormones or growth regulators can affect active sucrose uptake. Hosford et al (1984) observed that the concentrations of auxins and cytokinins found in roots during the growing season were different for mangold, chard, and sugarbeet.…”

“…Hosford et al (1984), Saftner and Wyse (1984), and Saftner (1986) have observed that hormones or growth regulators can affect active sucrose uptake. Hosford et al (1984) observed that the concentrations of auxins and cytokinins found in roots during the growing season were different for mangold, chard, and sugarbeet. They suggested that ABA may have a function of inhibiting xylem differentiation while promoting cell division and sucrose uptake.…”

“…Subsequent growth is by cell enlargement and cell division simultaneously within each of 6 to 8 of the inner rings (Milford, 1973(Milford, , 1976Doney et al, 1981). Hosford et al (1984) found that cambial initiation in mangold, chard, and sugarbeet, three greatly differ ent subspecies of Beta vulgaris L., were similar, indicating this was not a factor affecting dry matter and sucrose accumulation. High sugar varieties have a greater number of well-developed cambia than high yield varieties, and ring density also is higher for sugar types (Milford, 1973(Milford, , 1976Wyse, 1979;Doney et al, 1981Doney et al, , 1985.…”

Hormonal control of endoreduplication in sugar beet (Beta vulgaris L.) seedlings growing in vitro

“…Butterfass (1966) concluded that sugar beet plants with high endoreduplication have the lowest yield and suggested breeding tetraploid lines with low endopolyploidisation. On the other hand, there are different phytohormone levels in sugar beet genotypes that differ in root anatomy and sucrose concentration (Hasford et al. 1984).…”