Species richness and composition of arbuscular mycorrhizal fungi occurring on eucalypt trees (Eucalyptus camaldulensis Dehnh.) in rainy and dry season

River red gum (Eucalyptus camaldulensis Dehnh.), the most commonly planted eucalypt species globally, has several advantages and is widely used for many purposes, which makes the tree important. Mycorrhizal establishment in eucalyptus has been known for many years, and the benefits of this symbiosis have been commercially explored. The main goal of this research was to assess the diversity and distribution of arbuscular mycorrhizal fungi (AMF) on eucalyptus planted in agricultural fields in the rainy and dry season. Fields were chosen in ten different sites located in four provinces in the northeast of Thailand. Rhizosphere soil and root samples were collected and the number of AMF spores and AMF root colonization were assessed. The number of AMF spores was higher in the rainy season than in the dry season, while AMF root colonization was higher in the dry season than in the rainy season. On the basis of morphological identification of AMF, a total of 35 AMF fungal taxa in eight genera were identified, ten belonging to Acaulospora, one to Dentiscutata, one to Entrophospora, 16 to Glomus, three to Gigaspora, one to Racocetra, two to Scutellospora, and one to Septoglomus. Glomus was the dominant genus followed by Acaulospora. Relative abundance, and frequency of occurrence were higher in the rainy season than in the dry season. Racocetra fulgida was the most common species with a frequency of occurrence of 90% in rainy season, and 80% in dry season. Species richness, Simpson's index of dominance and Shannon-Wiener index of diversity were not significantly different between both seasons

Effects of Lasia spinosa Thw. on growth rate and reproductive hormone of weaned Swamp buffalo and Murrah X Swamp buffalo calves

The effects of Lasia spinosa Thw. on growth rate and plasma Oestradiol 17- β (E2), Progesterone (P4) and Testosterone (T) were studied in 16 male and female swamp (SS) buffaloes and Murrah x Swamp buffalo crossbreeds (MS) calves. The treatment group was fed with a concentrate supplemented with 30 g of dry powder of L. spinosa/head/d for 7 months. It was found that L .spinosa could have effect on male and female buffalo growth rate. The growth rate of male SS treated group were 130 g/d higher than control group. In female both SS and MS buffalo, the highest growth rate (830 to 840 g/d) was found after the 2nd month of treatment while a reduction in growth rate (-1,030 to - 450 g/d) was found in the 3rd month. After that the growth rate of SS and MS gradually increased until the last three months to 200 and 80 g/d in average, respectively. In female MS, plasma E2 in the treated group was lower than control group during Jan to Jul. Similar result was found in SS female, level of plasma E2 in treated group was lower than in control group in the first and last three month and there was no difference of plasma E2 in May. In MS male, the level of plasma E2 of treated group was higher than control group in Jan, Mar, Apr and Jul. In SS male, the level of plasma E2 of treated group was higher than control group in every month except in Jul. In female SS, L. spinosa could decreased plasma P4 through the experiment and could not have an effect on plasma P4 in female MS and plasma T in male buffalo calves. In conclusion, the addition to the concentrate of dry powder of L. spinosa 30 g/headl/d had an effect to increase growth rate in male SS and female MS buffalo calves, decrease plasma E2 in female both SS and MS and male SS and decrease plasma P4 in female SS

Solubilization and transformation of insoluble zinc compounds by fungi isolated from a zinc mine

Fungi were isolated from zinc-containing rocks and mining soil. They were screened for the ability to solubilize and transform three insoluble zinc compounds: ZnO, Zn3(PO)4, and ZnCO3. Fungi were plated on potato dextrose agar (PDA) medium which was supplemented with 0.5% (w/v) of insoluble zinc compounds. Of the strains tested, four fungal isolates showed the highest efficiency for solubilizing all the insoluble zinc compounds, producing clearing zone diameters > 40 mm. These were identified as a Phomopsis spp., Aspergillus sp.1, Aspergillus sp.2, and Aspergillus niger. Zinc oxide was the most easily solubilized compound and it was found that 87%, 52%, and 61% of the tested fungi (23 isolates) were able to solubilize zinc oxide, zinc phosphate, and zinc carbonate, respectively. Precipitation of zinc-containing crystals was observed in zinc oxide-containing agar medium underneath colonies of Aspergillus sp.1, and these were identified as zinc oxalate. It is suggested that these kinds of fungi have the potential application in bioremediation practices for heavy metal contaminated soils