Cyclophysis and topophysis influence in Populus deltoides Bartr from cutting-source formation to commercial plantation

Abstract

Commercial propagation of Salicaceae, carried out through cuttings, is influenced by ortet-ramet relations. The most frequently cited relations in the literature are topophysis and cyclophysis. The aim of this work was the study of topophysis and cyclophysis affecting growing shoots and rooting of P. deltoides cuttings from cutting-source formation to the first year in the commercial plantation. The results obtained that cyclophysis affected the new plant architecture as much as growing rate. The cuttings made on diagravitrophic ortets generate plants with: more horizontal branches, more meters per branch, more leaves and biomass, according to ortogratrophic ortets. The differences between the measured parameters point out a residual effect in the growing habit of the cutting into the ortet and the relation between explant efficiency and its situation on mother plant. The residual effect was made evident in the new plant formation. The topophysis modify rooting, being apical and basal cuttings bigger than intermediate-position cuttings. The low rooting percentage in intermediate-position cuttings (5 p. 100) could have physiological or genetical origins. These causes could not be clarified in our experiences. The topophysis and cyclophysis effects over cutting rooting and first year growing of plants in the cutting-source, determine the attainment of a highly heterogeneous population. In agreement with these results and in order to improve the commercial plantations in their first stages, the origin of plant material must be chosen considering the topophysis and cyclophysis effects