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Fungal endophytes and epiphytes in needles of Picea abies (L.) Karst. from natural and urban areas in northern Italy.The foliar fungal endophytes community inhabiting needles of Picea abies (Norway spruce) has not been well documented. In this study, carried out in Northern Italy, needles were collected in the years 2003 -2004 in Bagni di Masino and Passo S. Marco (natural locations) and in Milano and Pavia (urban areas). Needles were plated and scored for hyphal outgrowth of endophytes to observe composition and distribution pattern. Both colonization percentage and number of taxa were higher in needles collected in natural locations. There was a large difference in the infection levels between natural and urban areas, portion of the needle (the distal portion showing the largest number of colonies) and among the different needle age classes, with the youngest needles being virtually endophytes free and the 5 and 6 age classes being the most colonized. Thus Norway spruce foliar endophytes population appears to be influenced by age and portion of the needle and location. In the year 2003 fungal epiphytes were also investigated to compare the two different populations. Results analisys show a different distribution of endophytic and ephyphitic taxa, some species being mostly isolated in the natural locations others in the urban ones, thus indicating the presence of different clusters. Zythiostroma pinastri and Tiarosporella parca were the most frequent endophytes in natural locations while Sphaeropsis sapinea was common in urban areas. Among the epiphytes Alternaria alternata, Aureobasidium, and Cladosporium were ubiquitous taxa, Phomopsis was mostly isolated in natural locations.

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An experiment to quantify the response of unnodulated, fertilized European black alder (Alnusglutinosa (L.) Gaertn.) seedlings to progressive water stress showed contrasting drought tolerance among five clones, using stomatal conductance, leaf area, and height as indices of drought sensitivity. In particular, one rapidly growing clone (AG 8022-14) showed the ability to moderate changes in water stress more efficiently than the more slowly growing clones. After 30 days of moderate levels of water stress, clones that had higher stomatal conductance also had greater leaf area and height growth. Leaf area and height were both sensitive to plant water status, although no threshold of stress associated with a cessation of leaf area or height expansion was found even though stomatal conductance decreased to 0.05 cm s−1 under severe water stress.