Contributions of the stem to rooting in Eucalyptus grandis Hill ex Maid,stem cuttings

An additional wound at the base of one-node stem cuttings of Eucalyptus grandis increased rooting. Girdling intact shoots reduced rooting in cuttings harvested from them, while girdling cuttings at setting had little effect, suggesting that the internal phloem was active in basipetal transport in the stem. The vertical distribution of roots in additionally wounded cuttings also suggested a changed pattern of efflux from the internal phloem, as well as an increase in water uptake. In one-leaf cuttings more roots emerged from the leaf trace sector of the stem than from the trace of the absent leaf. In two-leaf cuttings the circumferential distribution of roots was uniform except in cuttings (a) reduced to a half-round cross-section at the base, in which rooting was more profuse at the lower of two sites of root emergence, and (b) from lateral coppice shoots whose stems were red-pigmented above with anthocyanins, in which there was less rooting than expected in the red sector. Stem volume was well related to rooting ability, largely explaining variation due to the original position of the cutting within the shoot and crown.