Rooting and establishment of Calabrian pine plantlets propagated in vitro: influence of growth substances, rooting medium and origin of explant

Abstract

SUMMARY The effect of auxins and a cytokinin on induction of roots in cultured axillary shoots of Pinus brutia Ten, has been tested. Auxin was crucial for root initiation and the rooting response varied according to the type and concentration of auxin applied. Both auxin and cytokinin and the interactions between them affected the quantity and quality of the induced roots. Aerated non‐sterile tap water was an effective rooting medium, comparable to agar. After planting out into soil, some of the influences of auxin and cytokinin could still be seen after six months. However, roots developed normally in the soil, displaying dichotomous lateral branches. The results draw attention to the need for care in the choice and application of the medium for the initial induction of roots. Results of greenhouse trials indicated that the most vigorous plants were obtained via the axillary shoots.

Micropropagation Via Axillary Bud Proliferation from Seedlings and Juvenile Shoots ofPinus patulaSchiedeetDeppe

“…Reported data for rooting of in vitro shoots produced from seedlings vary greatly, e.g. 5,7 % for Pinus canariensis (Martinez Pulido et al, 1994),50 % for Pinus strobus (Chesik et al, 1991), 64 % for Pinus sylvestris (Zel et al, 1988), 86 % for Pinus radiata (Horgan and Aitken, 1981) and 73 to 100 % (depending on clones) for Pinus brutia (Abdullah et al, 1989). Similarly, investigations involving juvenile shoots explants, yielded results of 32 to 84 % rooting for various clones of Pinus brutia x Pinus halepensis (Scaltsoyiannesetal., 1994) and 78 % rooting for Pinus pinaster (Dumas and Monteuuis, 1995).…”

“…In some Pinus spp., such shoots have been obtained in vitro from seedling Pinus patula seedlings were grown in composted explants (e.g. Horgan and Aitken, 1981;Mudge, pine bark and housed in a nursery tunnel which was 1986; Abdullah et al, 1986Abdullah et al, , 1989Zel et al, 1988; covered with Patilux plastic and surrounded with Baxter et al, 1989;Austin Burns et al, 1991;Jang 55 % windbreaking shade-cloth. The seedlings were and Tainter, 1991), juvenile/ fascicle shoots (e.g.…”

Micropropagation of a Casuarina hybrid (Casuarina equisetifolia L. × Casuarina glauca Sieber ex Spreng) following facilitated seed germination

“…Casuarina seems to belong to the class in which exogenous auxin is required and can stimulate adventitious root formation. However, the type and concentration of auxin that determine optimal rooting response depends mainly on species, type of explant tissue and the developmental stage of the plant (Abdullah et al 1989;De Klerk et al 1997). Fig.…”

Propagation from axillary buds and anatomical study of adventitious roots of Pinus taeda L.

“…The use of exogenous auxin is usually required for the induction of adventitious roots in difficult-to-root species. For conifers, α-naphthaleneacetic acid (NAA) is the most commonly used, sometimes in combination with cytokinins (Abdullah et al, 1989). Mehra-Palta et al (1978) achieved higher percentage of rooting (50%) in P. taeda combining 0.54 µM NAA and 0.22 or 0.04 µM BAP in Gresshoff and Doy modified culture medium (GDm), while Mott and Amerson (1981) succeeded in rooting loblolly pine with a combination of 2.69 µM NAA and 0.44 µM BAP added to the same medium.…”