Abstract
The major carbohydrates stored in carrots are sucrose, glucose and fructose. The ratio of sucrose to reducing sugars varies between cultivars, with early forcing types generally having a higher level of reducing sugars while storage types have a greater proportion of sucrose.
In an early forcing cultivar, Super Sprite, high acid invertase activity was correlated with low levels of stored sucrose. As acid invertase activity decreased, the levels of reducing and non-reducing sugars appeared to be related to a balance between alkaline invertase and sucrose synthetase activities.
Foliar applications of gibberellic acid at 35 and 42 days after sowing reduced the root/shoot ratio while similar applications of chlormequat chloride marginally increased the ratio. Both growth regulators temporarily increased sucrose stograge, but only gibberellic acid consistently reduced hexose accumulation.
Gibberellic acid reduced acid invertase activity following both applications while only reducing the activities of sucrose synthetase after the first application and alkaline invertase after the second application, respectively. Chloremequat chloride increased acid invertase activity after the first application but otherwise has no effect on the activities of the enzymes studied. The significance of changes in assimilate partitioning are discussed in relation to published schemes on carbohydrate storage in root vegetables.
Similar content being viewed by others
References
Austin RB and McLean MSM (1972) Some effects of temperature on the rates of photosynthesis and respiration of Phaseolus vulgaris L. Photosynthetica 6: 41–50
Benjamin LR and Wren MJ (1980) Root development and source-sink relations in carrot, Daucus carota L. J Exp Bot 31: 1139–1146
Carlton BC and Peterson CE (1963) Breeding carrots for sugar and dry matter content. Proc Amer Soc hort Sci 82:332–340
Fick GW, Williams WA and Loomis RS (1971) Recovery from partial defoliation and root pruning in sugar beet. Crop Sci 11: 718–721
Freeman RE and Simon PW (1983) Evidence for simple genetic control of sugar type in carrot (Daucus carota L.) J Amer Soc hort Sci 108: 50–54
Giaquinta RT, Lin WL, Sadler NL and Franceschi VR (1983) Pathway of phloem unloading of sucrose in corn roots. Plant Physiol. 72:362–367
Hole CC, Barnes A, Thomas TH, Scott PA and Rankin WEF (1983) Dry matter distribution between the shoot and storage root of carrot (Daucus carota L.). 1. Comparison of varieties. Ann Bot 51: 175–187
Hole CC, Thomas TH, Barnes A, Scott PA and Rankin WEF (1984) Dry matter distribution between shoot and storage root of carrot, parsnip, radish and red beet. Ann Bot (in press)
Hole CC, Thomas TH and McKee JMT (1984) Sink development and dry matter distribution in storage roots. Plant Growth Regulation This issue 2:000-000
Lester GE, Baker LR and Kelly JF (1982) Physiology of sugar accumulation in carrot breeding lines and cultivars. J Amer Soc hort Sci 107: 381–387
Neumannvon K-H and Schwab B (1975) Untersuchungen über den Einfluss von Gibberellinsäurespritzungen auf den Ertrag, die Anatomie der Wurzel und die Karotinverteilung bei Karotten. Z Pflanzenern Bodenk 1:19–23
Pontis HG, Wolosiuk RA, Fernandez LM and Bettinelli B (1972) The role of sucrose and sucrose synthetase in Helianthus tuberosus. In: (eds). Piras R and Pontis HG, Biochemistry of the Glycosidic Linkage pp 239–265. New York, London: Academic Press
Ricardo CPP (1974) Alkaline β-fructofuranosidases of tuberous roots: possible physiological function. Planta 118:333–343
Ricardo CPP and apRees T (1970) Invertase activity during the development of carrot roots. Phytochem 9:239–247
Ricardo CPP and Sovia D (1974) Development of tuberous roots and sugar accumulation as related to invertase activity and mineral nutrition. Planta 118:43–55
Saftner RA and Wyse RE (1980) Alkali cation/sucrose co-transport in the root sink of sugar beet. Plant Physiol 66:884–889
Silvius JE and Snyder FW (1979) Photosynthate partitioning and enzymes of sucrose metabolism in sugarbeet roots. Physiol Plant 46: 169–173
Steingrover E (1981) Storage of osmotically active compounds in the taproot of Daucus carota L. J Exp Bot 34:425–433
Thomas TH, Barnes A and Hole CC (1982) Modification of plant part relationships in vegetable crops. In: McClaren JS, ed. Chemical Manipulation of Crop Growth and Development, pp 297–311. London: Butterworth
Wolf DD and Ellemore TL (1975) Automated hydrolysis of nonreducing sugars and fructosans from plant tissue. Crop Sci 15:775–777
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
McKee, J.M.T., Thomas, T.H. & Hole, C.C. Growth regulator effects on storage root development in carrot. Plant Growth Regul 2, 359–369 (1984). https://doi.org/10.1007/BF00027295
Issue Date:
DOI: https://doi.org/10.1007/BF00027295