Carbohydrate and nitrogen fractions of the inner bark of loblolly pines under moisture stress

Abstract

In comparison with controls, 40-year-old loblolly pines (Pinus taeda L.) subjected to drought showed a marked increase in reducing sugars, nonreducing sugars, and total carbohydrates; and an approximately equivalent decrease in starch. The increase in sugars apparently was primarily the result of a decrease in growth rate and not hydrolysis of starch. Changes in the inner bark of trees stressed by continuous flooding followed the same basic pattern except that the marked increase in sugars occurred later, after severe stress had been established; stress probably was due to root failure. Drought and flooding had no effect on accumulation of amino N. Initially, synthesis of insoluble (protein) N was depressed but later the trend was reversed.