SEASONAL-CHANGES IN NONSTRUCTURAL CARBOHY DRATES IN SILVER-LEAF NIGHTSHADE (SOLANUM-ELAEAGNIFOLIUM CAV)

The levels of non-structural carbohydrates (TNC) in the roots, root co llar and stems of S. elaeagnifoli collected from field margins, cotton fields and olive plantations were determined monthly over a period of 1 year. The roots, and to a certain extent the root collar, were the organs with the largest carbohydrate reserves. The carbohydrate level was lowest at the time of flower bud formation. There was a build-up o f TNC reserves between flowering and fruit maturation over periods of 2, 4 and 5 months from plants growing in cotton fields, field margins and olive plantations respectively. Changes in TNC are influenced more by the phenological stage of the plant than by soil humidity or tempe rature. The implications of these findings in defining a control strat egy for this weed are discussed.