Effect of soil and plant water relations on rooting of Populus × euramericana stem cuttings

摘要

Studies on Populus ×euramericana (Dode) Guinier cv. ‘Robusta’ wereconducted to examine the rooting behaviour and changes in water potentialduringrooting, as influenced by the initial water potential of the cutting at twosoilwater potentials (−0.006 and −0.06 MPa). Differencesinthe initial water potential of the cuttings was achieved by three pretreatmentsi.e., fresh, soaked and dried. Initial Ψshoot was −1.45,−0.10 and −2.10 MPa in fresh, soaked and driedcuttings, respectively. Soil moisture had a major effect on rooting. Waterstressed cuttings took a longer time to root and had fewer roots. Pre-soakingofcuttings stimulated rooting particularly under the drier soil moistureconditions. Initially the water potential of cuttings decreased with time andwith the formation of roots it stabilized in all the pretreatments.Resistance-to-flow measurements suggested the development of tyloses and theestablishment of new xylem. No relationship was evident between stomatalresistance of leaves and water potential of cuttings. The starch content of thestem cuttings decreased significantly with time irrespective of treatment.