Influence of explant selection on the shoot-forming capacity of juvenile tissue of Pinusradiata

Abstract

The shoot-forming capacity of Pinusradiata D. Don juvenile explants under tissue culture conditions was examined. Three types of explant were used: whole embryos; cotyledons excised from whole embryos which had been cultured for 1 week on the shoot initiation medium; and cotyledons excised from 1-week-old aseptically germinated seeds. The average number of rootable shoots produced per seed in 12–13 weeks was 9 for excised embryos, 18 for their separated cotyledons, and 180 for the cotyledons from germinated seeds. Induction of a smooth-surfaced, yellow–green, nodular meristematic tissue appears to be a requirement for the formation of large numbers of adventitious shoots. By extending the culture period from 12 to 24 weeks more than 1300 shoots were formed from the cotyledons of one germinated seed. To date, no other conifer tissue culture method has been reported to give such a large number of adventitious shoots of the same clone in a first generation.

Multiplication of Meristematic Tissue: A New Tissue Culture System for Radiata Pine

“…With radiata pine, formation of meristematic tissue is a prerequisite for first-generation adventitious shoots (1). Meristematic tissue, which forms on whole embryos, seedling shoot tips, and excised cotyledons after three weeks on a cytokinin medium, subsequently forms shoots on a cytokinin-free medium (1,13,25,26).…”

In vitro adventitious shoot formation from embryonic and cotyledonary tissues of Pinus brutia Ten.

“…The aim of the present study was two-fold: (1) to develop a method for the induction of adventitious buds on two types of explant: excised whole embryos, and excised cotyledons from treated seeds of Brutian pine, (2) to stimulate the development of these buds into shoots. This is, we believe, the first published account of the development of a suitable procedure for the in vitro culture of this species.…”

Vitrification in Micropropagation

“…Aitken et al (1981) found that the translucent shoots that formed on vitrified Pinus radiata cultures were slow to elongate, but grew into normal shoots if left on the same medium for 2 to 3 months. Aitken-Christie and Thorpe (1985) described three types of shoots that could be formed, i.e., waxy shoots, which were similar to seedling shoots, wet shoots, which were dark green with the needles stuck together and lacked abundant epicuticular waxes, and translucent shoots, which were water-soaked and did not survive transfer from in vitro conditions.…”