When present, stilbene synthase leads to the production of resveratrol compounds, which are major components of the phytoalexin response against fungal pathogens of the plant and are highly bioactive substances of pharmaceutical interest. White poplar (Populus alba L.) was transformed with a construct containing a cDNA insert encoding stilbene synthase from grapevine (Vitis vinifera L.), under the control of the cauliflower mosaic virus (CaMV) 35S promoter, and a chimeric kanamycin resistance gene. Southern blot hybridization analysis demonstrated the presence and integration of exogenous DNA sequences in the poplar genome. Expression of the stilbene synthase-encoding gene in different transgenic lines was confirmed by Western blot and Northern analyses. Compared to the controls, in the transgenic plants two new compounds were detected and were identified as the trans- and cis-isomers of resveratrol-3-glucoside (piceid) by high-pressure liquid chromatography (HPLC), UV spectrophotometry, electrospray mass spectrometry (HPLC-ESI-MS) and enzymatic hydrolysis. Since poplar is a good biomass producer and piceids are accumulated in substantial amounts (up to 615.2 microg/g leaf fresh weight), the transgenic plants represent a potential alternative source for the production of these compounds with high pharmacological value. Despite the presence of piceid, in our experimental conditions no increased resistance against the pathogen Melampsora pulcherrima, which causes rust disease, was observed when in vitro bioassays were performed.

Tests were carried out m controlled environments to ascertain the effects of some physical, chemical and biological characteristics of soil on the spread o\ Rosellinia necatrix and on the development of its infection in poplars. Following the results obtained, cultivation techniques have been suggested which could prevent the diffusion of the fungus or reduce the damage it causes.

Accurate and frequently updated tree volume estimates are required for poplar plantations, which are characterized by fast growth rate and short rotation. In this study, we tested the potential of terrestrial laser scanning (TLS) as a reliable method for developing nondestructive tree volume allometries in poplar plantations. The trial was conducted in Italy, where 4- to 10-year-old hybrid plantations were sampled to develop tree crown volume allometry in leaf-on conditions, tree stem volume, and height-diameter allometries in leaf-off conditions. We tested one-entry models based on diameter and two-entry models based on both diameter and height. Model performance was assessed by residual analysis. Results indicate that TLS can provide accurate models of tree stem and crown volume, with percentage of root-mean-square error of about 20 percent and 15 percent, respectively. The inclusion of height does not bring relevant improvement in the models, so that only diameter can be used to predict tree stem and crown volume. The TLS-measured stem volume estimates agreed with an available formula derived from harvesting. We concluded that TLS is a reliable method for developing nondestructive volume allometries in poplar plantations and holds great potential to enhance conventional tree inventory and monitoring. Study Implications: Terrestrial laser scanning (TLS) is a technique that allows nondestructive measurement of the three-dimensional structure of a tree with high precision and low cost. The ability of TLS to measure both tree crown volume and tree position can be effective to test optimal spacing requirements and also to test innovative schemes such as mixed or polycyclic poplar plantations. The spatially explicit nature of TLS measurements allows better integration with different remotely sensed sensors, which can be used in combination with TLS, enabling a multiscale assessment of poplar plantation structure with different levels of detail, enhancing conventional tree inventory and supporting effective management strategies.

Over the last 30 years in Italy, a high percentage of tree plantations have failed to achieve the objective of enhancing the quality of forest products, and also restoring/ rehabilitating abandoned or degraded agricultural lands. In this study, we evaluated the effects of nursery cultivation in large, novel containers and duration of cultivation on early field establishment of 2-year-old seedlings of Quercus robur L. and Juglans regia L. Two sizes (9800 and 15,500 cm 3 ) of a new container (Superoots Air-pot Ò ) and one size (4900 cm 3 ) of a traditional container (Plastecnic Ò ) were tested and seedlings were sampled for shoot and root growth and biomass allocation. Prolonging the cultivation period to 2 years had a positive effect on both species, with a marked increase in above-and belowground biomass, maintaining a desirable balance between shoot and root systems. Both sizes of Air-pots for Q. robur and the bigger Air-pot for J. regia produced seedlings that were taller than 1.5 m, with a low branch component combined with a high frequency of apical dominance. The quantity and size of first order lateral roots varied between years within containers, and increased in deeper substrate layers during the second year. Early field results did not show marked signs of transplanting stress, but with low height growth in all treatments. Seedlings grown in both Air-pots exhibited well-developed and wellstructured root and shoot systems, thus showing promise in the establishment of high quality timber plantations of fine hardwoods; such attributes can be beneficial wherever