Abstract:With split-root pot experiment and using optical and electrical micro scopes, the growth of root hair of maize under different irrigation patt erns, i.e., irrigated on both halves of the pot (conventional irrigation, CI ), on one half only (fixed partial root zone irrigation, FPRI), and on both halv es alternatively (alternate partial root zone irrigation, APRI), was observed. T he observation after 40 days of treatment showed that in nonirrigated root zone of FPRI, the length proportion of root covered by vestigial root hairs was 20.96%, being higher than that in other zones. In addition to some bletting spots, the root system in irrigated zone of FPRI turned yellow, rootbranching deteriorated to some extent, and the root hair density on the section with thick root hairs was lower than that in nonirrigated zone. However, both the length proportion of root covered by vestigial root hairs (15.72%) and the deterioration of root hair were lower than those in nonirrigated zone. As for CI, the root appearance and root hair growth were similar to those of the FPRI irrigated zone. As for the early and late irrigated root zones of APRI, the root hair density on the section with thick root hairs was high. The length proportion of root covered by vestigial root hairs was 9.77% and 10.38% for these two root zones, respectively, being lower than that in any root zones of FPRI and CI. It was suggested that alternative partial root zone irrigation was more beneficial to the growth of root hair than fixed partial root zone irrigation and conventional irrigation.