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Sucrose utilization and mineral nutrient uptake during hairy root growth of red beet (Beta vulgaris L.) in liquid culture

Shin, K.S., Chakrabarty, D., Ko, J.Y., Han, S.S., Paek, K.Y.
Plant growth regulation 2003 v.39 no.2 pp. 187-193
Beta vulgaris, roots, in vitro culture, genetic transformation, Rhizobium rhizogenes, developmental stages, carbohydrate metabolism, sucrose, nutrient uptake, ammonia, nitrates, enzyme activity, beta-fructofuranosidase, culture media, chemical composition, glucose, fructose, quantitative analysis
Information concerning the sugar status of plant cells is of great importance during all stages of the plant life cycle. The aim of this work was to study primary carbohydrate metabolism in hairy roots of red beet. Growth of hairy roots of red beet in vitro and changes in concentration of major nutrients and sugar in the media were measured over a growth cycle of 16 days. We have also determined the levels of key enzymes in the pathways of sucrose metabolism. Sucrose concentration decreased as hairy root growth proceeded while no change in glucose and fructose levels in the medium was found during the first 3 days indicating that external sucrose is preferably taken to the cell before it is hydrolyzed by extracellular invertase. The increase in glucose and fructose levels in the media after 5 days of culture indicates extracellular hydrolysis of sucrose which was further supported by the activity of acid invertase observed during that time in the culture medium. The uptake of mineral nutrients by hairy root of red beet was monitored continuously during the culture cycle. The preferential use of NH4+ over NO3- at the beginning of the culture and acidification of culture media were the two most notable results concerning nitrogen nutrition during hairy root growth of red beet.