evaluating two methods of poa pratensis cv. barimpala root in effect of plant growth regulators and irrigation treatments

abstract several root measuring methods have been developed until now but there is no single method of root measurement applicable for all situations. this study was conducted to evaluate the effects of a single trinexapac-ethyl (te) and paclobutrazol application on kentucky bluegrass root growth under three irrigation treatments. evaluating of root length density (rld), root surface area (rs) and average root diameter were measured using two methods: newman and bohm method, and leaf area meter model (delta-t-scan image analysis system). the experiment was a split-plot factorial based on randomized complete block design (rcbd) with three replications. irrigation treatment had no effect on root length density. paclobutrazol reduced root length density in the second method but had no significant effect on the first. the results of two methods are different and both of them are acceptable in certain situation. in order to reliable study on root, we ought to find the acceptable method performance with due attention to the root characteristic and the type of factor that we evaluate. finally with high density of roots in turf grass the second method is recommended.