Effect of thiamine treatments on the population growth of aphids (R. padi) on
barley plants (cv. Lina). Twenty aphids were added to 7 days old plants and the
numbers of aphids were counted after 1 week. (A) Different concentrations of
thiamine were added to the nutrient solution for 5 days. Aphid infestation started at
24 h after the last thiamine addition. (B) Seeds were soaked in different concentrations
of thiamine or water before germination. The results are means (±s.e.) of six
(A) or five (B) replicates. Asterisks indicate significant differences between control
and treated plants, t-test (⁄P 6 0.05; ⁄⁄P 6 0.01; ⁄⁄⁄P 6 0.001).