Effects of sorne organic compounds (maltose, sucrose, vitamins) on the shoot biomass of Allocasuarina verticülata (Lam.) L. Johnson (Casuarinaceae) Summary.-Allocasuarina verticillata, a N 2 -fixing tree (actinorhizal plant) reknowned for ils tolerance to lire and salinity, is used for fuel wood production, land reclamation, shelter belis and for ornamental purposes. Root explants from seedlings were used for micropropagation. Biomass of regenerated shoots was increased by adding maltose (3 ta 6 %) instead of sucrose to Murashige and Skoog (1962) basal medium. This treatment reduced callogenesis and increased shoot number and chlorophyll content. The very high rate of shoot multiplication makes this species of Casuarinaceae a promising candidate for reforestation of arid soils in subtropical and mediterranean countries.Résumé.-Allocasuarina verticillata, plante actinorhizienne et arbre fixateur d'azote, connu pour sa tolérance au feu et à la salinité, est utilisé en pays tropical pour la production de charbon, la régénération des sols, et l'installation de brise-vents et de plantations ornementales. Des ex plants racinaires de jeunes plantes peuvent constituer un matériel apte à la micropropagation. La biomasse des tiges régénérées à partir des racines sur le milieu de base Mu rash ige et Skoog (1962) est considérablement augmentée si on remplace le saccharose par le maltose (3 à 6 %). Ce traitement réduit la callogenèse, augmente le nombre de tiges régénérées ainsi que leur contenu en chlorophylle. Le très fort coefficient de multiplication obtenu in vitro suggère d'utiliser cette espèce dans des essais de reboisement en zone tropicale et méditerranéenne.

Eucalyptus maidenii plantations are typically fertilized to increase the yields of eucalyptus oil and timber. However, the application of chemical fertilizers is costly and can cause environmental pollution and soil erosion. Mycorrhiza fungi can facilitate the cultivation of optimal seedlings while promoting the growth of trees. To date, investigations into the inoculation of endomycorrhizal fungi to enhance the productivity of E. maidenii in Yunnan, China have not been undertaken. The species/dominant species of endomycorrhizal fungi on E. maidenii in Yunnan were isolated and identified. The effect of endomycorrhizal fungi on E. maidenii was elucidated. The major species of endomycorrhizal fungi that affect E. maidenii were ascertained. Bulk soil was collected from an E. maidenii plantation, and the species of endomycorrhizal fungi were investigated. The effect of the endomycorrhizal fungi on E. maidenii were analyzed via a single factor experimental design, where the number of spores of endomycorrhizal fungi in the seedling substrate were controlled. The major endomycorrhizal fungi species that affected E. maidenii were ascertained via stepwise regression analysis. Five endomycorrhizal fungal species were isolated from the bulk soil, with the dominant being Glomus aggregatum and Glomus mosseae. With higher counts of endomycorrhizal fungal spores in the seedling substrate, the infection rate and intensity of seedlings were observed to increase, as well as the NPK concentrations of the bulk soil. With the increased nitrogen concentration in the bulk soil, the nitrogen concentration of the aerial components of the seedlings also increased. The NPK concentrations in the bulk soil and seedlings, the second order lateral roots, the root activity, and the seedling height were significantly promoted by the presence of endomycorrhizal fungi (the third experimental treatment). The NPK concentrations of the bulk soil and seedlings, as well as the growth indices of seedlings increased through endomycorrhizal fungi inoculation. The major species of the endomycorrhizal fungi on E. maidenii were G. aggregatum, Glomus multicaule, and Claroideoglomus etunicatum.