Effect of rainfall exposure on leaf wettability in near-isogenic barley lines with different leaf wax content

摘要

Water retention, contact angle of water droplets, and amount of epicuticular wax on leaf surfaces were examined in two lines of near-isogenic barley with normal and glossy leaves. In addition, the effect of rainfall on the wettability of leaf surfaces was examined. Mean water retention of leaves from the 1st to 5th node was 5.6 mg/cm~2 in normal leaf linesand 12.8 mg/cm~2 in glossy leaf lines. The mean contact angle of water drops was 125 deg in normal leaf and 93 deg in glossy leaf. The mean epicuticular wax content was 17.3 #mu#g/cm~2 in normal leaf and 9.3 #mu#g/ cm~2 in glossy leaf. In glossy leaves, contact angles decreased with increasing duration of rainfall treatment. After treatment for 5 days, the angle was about 70 percent of that without rainfall treatmint. Reduction of epicuticular wax amount by rainfall exposure occurred in all leaf positions of both barley lines. The reduction rates in the normal leaf line were 10-20 percent. In the glossy leaf line, the reduction rates were 15 percent in the 1st leaves and about 50 percent in the 2nd-3rd leavea.