Fig. 1.

Effect of heat stress on levels of sucrose, glucose and fructose in pollen grains of wild-type and Nr mutant tomato plants. Mature pollen grains at anthesis were collected from wild-type (Pearson) and ethylene receptor mutant (Nr) tomato plants which were exposed for at least 14 days to either control (28/22 °C day/night) or mild chronic heat stress (MCHS; 32/26 °C day/night) conditions. Carbohydrate concentrations are presented as mean values ± SE (n = 3 independent experiments; pooled from at least 50 flowers each). In each category (control, black bars; MCHS, white bars), bars with different letters are significantly different by multiple comparison Tukey's HSD test (α = 0.05).