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Fig. 7. Mean maximum midday (MD: solar noon) net assimilation rate (A) (a, b) and stomatal conductance to water vapor (gs) (g, h) for fully expanded sunlit spring wheat leaves for day after 50% emergence (DAE) and development stages given during the (a, g) 1993 and (b, h) 1994 growing seasons, respectively. Histograms shown during 1994 in panel b (inserts c, d, e, and f) illustrate values of A from inflorescence emergence (DAE 81) until physiological maturity for (c, d) Wet (DAE 137) and (e, f) Dry (DAE 123) treatments, a period of accelerated senescence. Treatment inversion in the carbon dioxide (C) effect on values of A are denoted by up-pointing arrows in panel (b), which intersect approximately on DAE 124 (histogram panels c and d) for Wet, and on DAE 103 (histogram panels e and f) for Dry treatments. Histograms shown during 1994 in panel (h) (inserts i and j) illustrate values of gs for (i) Wet and (j) Dry treatments. Unlike the treatment inversion observed in the C effect for A (inserts c, d, e, f), no such effect was observed in gs (i, j). All measurements were simultaneous with, and sampled as described for gs in Fig. 2 and for A in Fig. 6. Symbols in legend, source of variance, and results from ANOVA same as described in Fig. 1. The above illustration was derived from measurements of as many as 960 leaves.
