Carbohydrate accumulation and partitioning in Pinus banksiana seedlings and seedling cuttings

Tests were conducted to identify possible relations between carbohydrates and callusing-rooting of Pinus banksiana Lamb, cuttings. Terminals, upper stems, and basal (1 cm) stems of 90-day-old untreated seedlings and seedling cuttings were analyzed for sucrose, total soluble reducing sugar, starch and total non-structural carbohydrate during propagation. Seedlings were evaluated in order to determine whether data for cuttings alone properly described carbohydrate-callusing-rooting relations under conditions where stock plants and cuttings were propagated in different environments. Results indicated that seedling terminals and upper stems, but not basal stems, accumulated the measured carbohydrates much like cuttings, though to lesser concentrations. Thus, carbohydrate accumulation by cutting terminals and upper stems would have been overestimated, based on cutting data alone. In terms of rooting, results indicated that: 1) Total carbohydrate accumulation in cutting basal stems was related to callusing-rooting, but a cause-effect relation was not established; 2) The positive relation between callusing-rooting and total carbohydrate accumulation was primarily due to accumulation of reducing sugar and starch, with reducing sugar predominant. 3) Reducing sugar/starch concentration ratios were the most sensitive and convenient indicators of specific carbohydrate differences within and between seedlings and cuttings.