Effectiveness of mycorrhizal inoculation in the nursery on growth and water relations of Pinus radiata in different water regimes.

We compared the performance of mycorrhiza-inoculated and non-inoculated radiata pine (Pinus radiata D. Don) seedlings in two field studies. In the first study, above ground growth of 2-year-old container-grown trees was compared after planting in two areas that differed in water availability. Mycorrhizal inoculation significantly improved above ground growth in the 2 years after planting in both areas, especially at the drier site. In the second study, the influence of Rhizopogon roseolus (Corda ex Sturm) Th. Fries and Scleroderma citrinum Pers. on xylem water potential and hydraulic conductance at the soil-root interface of trees established at the same sites was assessed. Nursery inoculations with R. roseolus and S. citrinum improved tree growth during the first 2 years after field outplanting, particularly at the drier site.

One step more towards taxane production through enhanced Taxus propagation.

We have developed a high-yielding procedure for the in vitro propagation of juvenile material of Taxus baccata involving a combination of seed handling and culture on WP culture medium supplemented with sucrose (2%), activated charcoal (0.5%) and BAP (22.19 mM) for 30 days, followed by 40 days on hormone-free medium. Shoot apical ends should be decapitated to obtain propagation rates up to 12- to 18-fold per subculture period (70 days). In this way the high genetic variability of the juvenile material can be used in the most productive way. In addition to producing large numbers of yew plants (difficult to get by traditional methods), this procedure allows the fast screening of individuals for their taxane content. A negative correlation between growth and secondary metabolite content was found for paclitaxel. The positive correlation with 10-deacetyl baccatin III accumulation reflects once more the commercial viability of using 10-deacetyl baccatin III extraction as an alternative to taxane production, but this time opening up the possibility of selecting genotypes with both characteristics: fast growth and high productivity.