Effect of jasmonic acid on the stomatal and nonstomatal limitation of leaf photosynthesis in barley leaves

The effect of long-term (7 days) and short-term (up to 2 h) treatment of barley plants with jasmonic acid (JA) on the components contributing to stomatal and nonstomatal limitation of photosynthesis was studied. Net CO2 assimilation rate (A) responses to intercellular CO2 concentration (C-i), i.e., A/C-i curves, were used to assess the photosynthetic ability. Long-term treatment of barley plants with JA led to a noticeable decrease in both the initial slope of the A/C-i curves and the maximum A at saturating C-i. The proportion of stomatal and nonstomatal factors in limitation of photosynthesis depended on the applied JA concentration. Short-term treatment with JA affected neither the stomatal conductivity for CO2 nor the rate of photosynthetic CO2 assimilation. We suggest that JA may affect photosynthesis indirectly, either as a stress-modulating substance, or through the alterations in gene expression.