study the phenology of lesser celandine (ranunculus ficaria) and effect of planting depth on sprouting of its tuberous -rroots

in order to study the phonological stages and growth period of invasive weed ranunculus ficaria based on degree days and to study the effect of planting depth on sprouting the tubers roots of this weed, two separate experiments were conducted in crd with 5 replications at ferdwosi university of mashhad in 2008. in the first study germinated tubers were planted in 5 cm depth and the observations were noted. in the second experiment, germinated tubers were planted in different depths of 0.25, 1.5, 2.5, 5, 7, 10, 15 and 20 cm. the results indicated that lesser celandine continued the growth until 1014 gdd and 4 phonological stages were recorded in this period. lesser celandine sprouted from all depths but required gdd for emerging from surface depths were less than 15 and 20 cm planting depth.