The antioxidant properties of two raw truffles (Terfezia claveryi Chatin and Picoa juniperi Vittadini) and five raw mushrooms (Lepista nuda, Lentinus edodes, Agrocybe cylindracea, Cantharellus lutescens, and Hydnum repandum) were tested by subjecting these truffles and mushrooms to different industrial processes (freezing and canning) and comparing them with common food antioxidants (alpha-tocopherol [E-307], BHA [E-320], BHT [E-321], and propyl gallate [E-310]) with regard to their ability to inhibit lipid oxidation. All of the truffles and mushrooms analyzed exhibited higher percentages of oxidation inhibition than did the food antioxidants according to assays based on lipid peroxidation (LOO*), deoxyribose (OH*), and peroxidase (H2O2). Frozen samples exhibited a small reduction in free radical scavenger activity, but the results did not show a significant difference (P < 0.05) with respect to the raw samples, while canned truffles and mushrooms lost some antioxidant activity as a consequence of industrial processing. All of the raw and frozen truffles and mushrooms except frozen Cantharellus improved the stability of oil against oxidation (100 degrees C Rancimat), while canned samples accelerated oil degradation. Antioxidant activity during 30 days of storage was measured by the linoleic acid assay, and all of the samples except canned Terfezia, Picoa, and Hydnum showed high or medium antioxidant activity. The Trolox equivalent antioxidant capacity assay was used to provide a ranking order of antioxidant activity as measured against that of Trolox (a standard solution used to evaluate equivalent antioxidant capacity). The order of raw samples with regard to antioxidant capacity was as follows (in decreasing order): Cantharellus, Agrocybe, Lentinus, Terfezia, Picoa, Lepista, and Hydnum. Losses of antioxidant activity were detected in the processed samples of these truffles and mushrooms.

The influence of arbuscular mycorrhizae (AM) on plant growth and Zn and Pb uptake by Lygeum spartum and Anthyllis cytisoides was studied in soils with different levels of these heavy metals. A. cytisoides is highly dependent on AM for optimal growth, while L. spartum is a facultative mycotroph.Mycorrhizal and nonmycorrhizal plants were grown in soil supplemented with 0, 10, 100 and 1000 mg of Zn kg -l soil or 0, 100 and 1000 mg of Pb kg -1 soil. Two different mycorrhizal fungi were separately studied: Glomus macrocarpum isolated from a non contaminated site and a strain of Glomus mosseae isolated from a soil contaminated with these metals. The infectivity of the fungi was not affected by the presence of Zn or Pb in the soil. In unamended soil, both fungi were equally effective in promoting plant growth, but when Zn or Pb were added to soils, G. mosseae was more efficient than G. macrocarpum in stimulating plant growth of A. cytisoides. A. cytisoides was unable to grow unless mycorrhizal. Metal addition to the soil induced a reduction in the biomass of L. spartum and of mycorrhizal A. cytisoides, and a decrease in shoot P concentration of mycorrhizal plants. The concentration of metals in the plants varied according to the amount added to the soil and to the inoculation treatment: at low doses, mycorrhizal plants showed equal or higher concentration of Zn or Pb than nonmycorrhizal ones; at higher doses, however, metal concentrations in the plants inoculated with G. mosseae were lower than those found in the corresponding controls, while the plants inoculated with G. macrocarpum showed similar (L. spartum) or even higher (A. cytisoides) levels than the controls.

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This work presents the first anatomical description of the mycorrhizal systems of Helianthemum almeriense, and of the structure and ultrastructure of the mycorrhizae formed by this plant species with the ascomycetes Terfezia claveryi and Picoa lefebvrei. Four different mycorrhizal systems are described, the club-shaped mycorrhiza being the most abundant. The type of mycorrhiza formed depended on the mycorrhiza culture conditions, but not on the fungal species. For both fungal species, H. almeriense formed an endomycorrhiza in natural field conditions, an ecto- and ectendomycorrhiza without a sheath in pot cultures, and an ectomycorrhiza with a characteristic sheath and Hartig net in in vitro cultures. This is the first report of a typical sheath in Helianthemum-desert truffle mycorrhizal associations. The results support the idea that culture conditions can induce changes in mycorrhiza morphology and that there is no clear barrier between the two main types of mycorrhiza organization in Helianthemum species. The ultrastructural study confirmed the regular presence of T. claveryi intracellular hyphae in direct contact with the host wall, a localization which seems to be a characteristic of the T. claveryi mycorrhiza organization. The P. lefebvrei mycorrhiza organization was characterized by intracellular hyphae with large amounts of electron-dense globules, probably with a lipidic content, and a warty ornamentation on the wall of the root external hyphae.

Our objectives were to investigate the proximate composition of two desert truffles (Terfezia claveryi Chatin and Picoa juniperi Vittadini) and to determine the effects of freezing and canning on proximate composition. The moisture content of T claveryi and P juniperi was 730.9 g kg −1 and 637.8 g kg −1 respectively; ash was 42.5 g kg −1 and 82.1 g kg −1 respectively; protein was 159.5 g kg −1 and 225.4 g kg −1 respectively; lipids were 69.5 g kg −1 and 199.4 g kg −1 respectively; fibre was 83.2 g kg −1 and 130.4 g kg −1 respectively; and carbohydrates were 645.5 g kg −1 and 366.6 g kg −1 respectively. The fatty acids composition showed high quantities of linoleic acid 18:2 (45.4% in T claveryi and 53.0% in P juniperi), the rest of the fatty acids in decreasing order were 16:0 > 18:1 > 18:3 > 18 : 0 + 22 : 0 > 20 : 0 + 24 : 0 > 14 : 0 + 22 : 1 > 15 : 0 + 16 : 1 + 17 : 0 + 21 : 0 in T claveryi and 18 : 1 > 16 : 0 > 18 : 0 + 18 : 3 + 16 : 1 + 20 : 0+22:1 > 14:0 + 24:0 > 15:0 + 17:0 + 22:0 in the P juniperi. Little loss of ash, protein and lipids was observed as a result of industrial processing (p < 0.05).