Oxygen isotope ratio of leaf and grain material correlates with stomatal conductance and grain yield in irrigated wheat

摘要: Theory (Craig and Gordon 1965; Dongmann et al. 1974; Sternberg 1986; Farquhar Lloyd 1993) suggests that the oxygen isotope ratio (d 18 O) of plant material should reflect evaporative conditions under which was formed, so differences in stomatal conductance show up d O. To test this theory we measured organic matter from flag leaves at anthesis grain harvest eight cultivars spring wheat (Triticum aestivum L.) grown irrigation each three seasons Mexico. The ranged widely average yield, with positively correlated. Supporting theory, Ol) found to correlate negatively for two seasons. significant correlations are consistent high having lower leaf temperatures kinetic fractionation factors, higher vapour pressure factors Peclet numbers, all combine result less enriched Ol. Yield (grain weight per square meter) also be significantly correlated 18Ol Ol as good a predictor yield conductance, better than carbon discrimination. Correlations between O Og) physiological parameters were clear. Significant negative Og temperature only during first season. By measuring cellulose extracted samples, difference (ecp) whole tissue assessed. ecp variable, more when Oc lower. Cultivar means 13 C related, required produce such relationship discussed.