JUVENILITY FACTORS RELATED TO THE ROOTABILITY OF CHESTNUT CUTTINGS

Differences in the rootability of chestnut (Castanea sativa Mill.) cuttings in the juvenile and mature form are reported.
To explain the differences, the content of growth substances and inhibitors were determined and anatomical changes related to the sclerenchyma ring were determined.

According to Leopold (1964) "physiologically the juvenile state can be described as a period when the plant is capable of exponential increase in size, when the plant develops characteristic morphological forms (leaves, stems, thorns, etc.)". It should be emphasized that the juvenile period is not a period in which the plant is necessarily devoid of an ability to flower.

Physiological expressions are also involved in juvenility and one of the most important is that related to rootability of cuttings.
For some woody plants which are shy rooting, cuttings taken in the juvenile stage often root more easily than those taken from mature plants.
This was known by plant propagators before the concept of juvenility became generally accepted.
This favorable effect on root formation by cuttings has been reported by some authors (Hess, 1961; Vieitez, 1963). Pilet (1968) reported that more enzymatic destruction of indoleacetic acid (IAA) occurred in older pea tissues, suggesting that the higher rootability of juvenile cuttings might be due to a higher auxin content.

To solve the problem of inducing root formation on cuttings of shy rooting woody plants as related to the juvenile-mature phase change, it would be helpful to understand the root formation mechanism.
At the present time three hypotheses can be put forward to explain difficulty in rooting certain cuttings:

1. lack of a balanced hormonal level or of certain growth cofactors (Hess, 1961).

2. presence or absence of some growth inhibitors (Barlow et al., 1961; Ooyama, 1962).

3. presence or absence of anatomical features such as a ring of sclerenchyma which would make rooting easier if absent or discontinuous (Beakbane, 1961).

The rootability of cuttings from juvenile and mature chestnut trees has been studied together with the possible physiological and histological changes involved.
The interest in rooting chestnut cuttings became apparent after the fungi Phytophthora cambivora (Petri) Buisman, P. cinnamomi Rands and Endothia parasitica (Murr.) P.J. & H.W. Anderson invaded and destroyed most of the chestnut trees in different

Symposium on Juvenility in Woody Perennials

E. Vieitez, A. Vieitez

https://doi.org/10.17660/ActaHortic.1976.56.31