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• We analysed the ectomycorrhizal (ECM) fungal diversity in a Mediterranean old-growthQuercus ilexforest stand from Corsica (France), whereArbutus unedowas the only other ECM host.• On a 6400 m2 stand, we investigated whether oak age and host species shaped below-ground ECM diversity. Ectomycorrhizas were collected underQ. ilexindividuals of various ages (1 yr seedlings; 3–10 yr saplings; old trees) andA. unedo. They were typed by ITS–RFLP analysis and identified by match to RFLP patterns of fruitbodies, or by sequencing.• A diversity of 140 taxa was found among 558 ectomycorrhizas, with many rare taxa.Cenococcum geophilumdominated (35% of ECMs), as well as Russulaceae, Cortinariaceae and Thelephoraceae. Fungal species richness was comparable above and below ground, but the two levels exhibited< 20% overlap in fungal species composition.• Quercus ilexage did not strongly shape ECM diversity. The two ECM hosts,A. unedoandQ. ilex, tended to share few ECM species (< 15% of the ECM diversity). Implications for oak forest dynamics are discussed.New Phytologist(2005)doi: 10.1111/j.1469-8137.2005.01382.x© New Phytologist(2005) [ABSTRACT FROM AUTHOR]

Present study aimed to observe the mineral accumulation added through effluent application and their influence on physiological functions and growth of Dalberia sissoo and ultimately to find out suitable combination of industrial and municipal effluent for their utilization in raising tree plantation. Dalbergia sissoo seedlings were irrigated with: canal water (T[sub 1]); municipal effluent (T[sub 2]); textile effluent (T[sub 3]); steel effluent (T[sub 4]); textile + municipal effluent in 1:1 ratio (T[sub 5]); steel + municipal effluent in 1:2 ratio (T[sub 6]); steel+municipal+textile in 1:2:2 ratio (T[sub 7]); and steel+textile in 1:2 ratio (T[sub 8]). Mineral accumulation, water relations and gas exchange, growth and biomass production were the recorded observations. Mortality occurred within a day for the seedlings in T[sub 4], 45 days in T[sub 6], and 60 days in T[sub 7] and T[sub 8] treatments. This was probably the result of high (P<0.01) Mn, Fe, Cu, and Zn and low N, P, K, Ca, and Mg concentration in different parts of the seedlings in these treatments affecting physiology and growth. Reduction in rate of photosynthesis (Pn) and transpiration (T) to the level of 90%, leaf water potential (LWP) and increased stomatal resistance (R) at two months of age is the indicator of metal toxicity in these treatments. Pn and T were 20 and 17% high in T[sub 2] treatment, respectively. However, the reduction was only 21 and 10% in Pn and 18 and 26%, respectively in the seedlings of T[sub 3] and T[sub 5] than that in T[sub 1] treatment. During nine months of observation, the seedlings of T[sub 2] and T[sub 5] maintained high LWP and same rate of Pn and T but they reduced significantly (P<0.01) in the seedlings of T[sub 3] treatment affecting biomass production. This was believed to be due to increase in Na concentration leading to decrease in Mg, Ca, Mn, Fe, Cu and Zn concentration and ratio of Mg/Na and Mg/K and increased ratio of N/Mg and K/Ca +Mg. The enhanced physiological functions in Ts treatment were probably the result of ameliorative effect of municipal effluent through increased mineral status producing biomass equivalent to that in T[sub 1] treatment at 10 months of age. The seedlings of T[sub 2] attained greater (P<0.01) height and collar diameter and produced 120 g seedling[sup -1] of dry biomass. The study suggests that addition of excess mineral elements leads to metal toxicity that adversely affects physiology and ultimately growth and productivity of tree seedlings. Mixing of effluents to ameliorate the toxic effects could be the better management practices for their use in tree irrigation. [ABSTRACT FROM AUTHOR]

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Whole plant acclimation to ozone exposure in growth-chamber cultivated radish (Raphanus sativus L. cv. Cherry Belle) was investigated. The primary goal was to separate developmental from physiological ozone acclimation processes. Plants were grown for 37 days at two different lengths of ozone exposure and a control treatment. After germination, seedlings were transplanted into controlled growth chambers and exposed to daytime (10 h) ozone (0.12 μl l-1) either on the next day (continuous ozone treatment) or three days later (intermediate treatment) and compared to a control (average ambient ozone concentration 0.01-0.02 μl l-1). Plants grown in ozone after transplanting accumulated considerably less biomass than the controls, but had higher dry weights than the intermediate treatment, implying an acclimation response. Photosynthetic capacity and nitrogen content of leaves decreased at high levels of ozone exposure resulting in an accelerated leaf senescence. No distinct leaf-level physiological acclimation to ozone exposure was seen based on gas exchange measurements. As an apparent compensatory response, plants exposed to ozone had higher leaf production rates than control plants, at the expense of root and hypocotyl growth. This developmental, whole-plant response appeared to be the most effective acclimation response to ozone exposure seen in radish. However, it did not fully compensate for the damage caused by ozone, since plants still showed considerable reductions in growth. [ABSTRACT FROM AUTHOR]