We hypothesize that drought-avoidance in Gutierrezia sarothrae populations is characterized by well-developed lateral roots. Root growth and hydraulic conductance were studied in four populations of Gutierrezia sarothrae. Seedlings from a Malta, Idaho (ID) seed source had four times higher root/shoot ratio (P<0.05), but only 17% hydraulic conductance of those from Tahoka, Texas (TA) seed source. Consequently, transpiration surface area of the ID seedlings was 17% that of the TA seedlings. There was no difference in total root length between the seedlings, but hydraulic conductance per unit root length was 3.8 fold greater (P<0.05) in the TA seedlings, which was accompanied by a lower specific lateral root length (P<0.05), thus greater [...]
