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Fig. 9. Midday (MD: solar noon) trends in leaf tissue total nonstructural carbohydrate concentration (TNC) (i.e., water-soluble sugars (glucose, fructose, sucrose), low and high molecular weight fructans, and starch). (a) At anthesis (day after emergence, DAE) 89 during 1994, the uppermost fully expanded sunlit flag leaf and all physiologically active leaves beneath the flag leaf (i.e., flag-1, flag-2, flag-3, and flag-4) were sampled in sequential order from the same culm, for each of 10 culms, from the top of the canopy height (Z) denoted by the left-most y axis. (b) The whole-canopy TNC profile represents the sum of the flag through flag-4 leaves denoted by right-most y axis. Each mean datum was derived from four individual assays (repeated measures) performed on a 30-mg sample (i.e., pooled sample taken from the thoroughly mixed powder of 10 freeze-dried leaves) across four replications sampled at MD (i.e., means based on n = 16). Symbols in legend and results from ANOVA same as described in Fig. 1. Vertical bars are 1 SE of replication means (i.e., n = 4). Percentages in parentheses above each mean histogram datum indicate relative CO2 enhancement at Dry and Wet, respectively. Source of variance in ANOVA are as follows: replication (R); CO2 (C); irrigation (I); and, canopy height (Z). The corresponding error term for each effect is given in parenthesis as follows: C (R x C); I (R x I); C x I (R x C x I); Z (R x Z); Z x C (R x Z x C); Z x I (R x Z x I); Z x C x I (R x Z x C x I). The above illustration was derived from measurements of as many as 800 leaves.
