Apple and pear root systems: induction, development, structure and function - Biology of Apples and Pears - page 90

Table . Relation between propagation capacity and primary

phloem structure in stems

Continuity of
fibre ring a

Propagation

Cultivar capacity % Mean

Apple rootstocks
'M. '

'M. ' Excellent

'M. '

'M. '

'M. ' Good

'M. '

'M.'

'M.' Fair

'M.'

'Crab C'

'Northern Spy' Poor

'Ivory's Double Vigour'

Scion cvs.
Apple
'Bramley's Seedling'

'Cox's Orange Pippin' Poor

'Lane's Prince Albert'

Pear
'Conference'

'Williams'' Poor

a Proportion of radii through the primary phloem blocked by scle-
renchyma.
From Beakbane ( ). Reprinted with permission from Nature ,
Macmillan Magazines Limited.

of a cutting. Characteristically there is callus formation and production of
root primordia along the margins of the wound (MacKenzie et al. , ). The

wounded surface permits penetration of synthetic auxin rooting compounds
and also there is probably a natural accumulation of auxins and carbohydrates
in the wounded area. Wounding by disrupting the sclerenchymatous sheath in
winter (hardwood) cuttings permits the formation of cambial salients, as noted
earlier.

Hartmann et al. ( ) present photographic evidence (in their publication,

courtesy W. Chantarotwong) that the presence of leaves and treatment of
the cutting base with auxin are both needed to induce vigorous rooting of
leafy (summer) cuttings of 'Old Home' pear. Removal of the leaves prevented