The Effect of Low Temperature and Drought on The Carbohydrate Content of Asparagus

Expanded shoots of asparagus (Asparagus officinalis) were found to contain sucrose, glucose, andfructose, while neither starch nor fructans could be detected. On the other hand, storage roots accumulate fructans, in addition to smaller amounts of sucrose, glucose, and fructose, while starch does not accumulate. Exposing asparagus to low temperature (15/5 °C) caused a rapid, short term increase in the sucrosecontent of the shoot and a simultaneous decrease in the fructan content in the roots. Long term low temperature treatment led to a sharp decrease in the sugar content and concomitant senescence of the shoots, whereas the fructan content of the roots increased. Withholding water during the cold treatment initially led to a fürther increase in the sucrose content ofthe shoot and also in the fructan content of the roots. However, after 50 days of drought in conjunction with low temperature, shoot sucrose content was decreased, root fructan content was unaffected and root sugar levels were increased, as compared with cold treatment alone. Drought in the absence of cold treatment led to sharp decreases in the glucose, fructose, and sucrosecontents of the shoot and in the fructan content of the roots. The results are discussed in terms of the effect of environmental stresses on the carbohydrate balance of asparagus plants.