MAESTRI Damian Modesto
congresos y reuniones científicas
Effects of different water deprivation levels on arbuscular mycorrhizae fungi associated to olive trees
PIERLUIGI PIERANTOZZI; ALEJANDRA BECERRA; MARIELA TORRES; DAMIÁN MAESTRI; EDUARDO TRENTACOSTE; CARLOS PUERTAS; EDUARDO NOUHRA
Simposio; VIIth International Symposium on Olive Growing; 2012
Olive trees have great adaptability to adverse soil conditions and are typically grown on marginal soils with low fertility. Water deficit and osmotic imbalance are the most common stresses affecting crops in arid and semi-arid regions. Tolerance to osmotic stress in plants is a complex phenomenon and involves many changes at the biochemical and physiological levels. However, the mechanisms behind the modulation of tissue water conductivity and osmotic adjustment appear to be affected by mycorrhizae colonization. The aim of this study was to evaluate the effect of water availability on mycorrhizal colonization of olive trees (cv. Arbequina) grown at two different agro-climatic environments. The experimental design included two water deficit treatments, one at 50% of the estimated crop evapotranspiration (Mendoza province) and another under natural rainfall (Cordoba province), and a treatment irrigated at 100% of the estimated crop evapotranspiration at both cultivation sites. The root-associated soil samples from each individual plant (n=10) were randomly collected at 10 to 20 cm depth. Each sample consisted of five bulked sub-samples (200 cm3 soil cores). The arbuscular mycorrhizal colonization rate was higher in treatments with lesser water availability; the average increments were found to be 42% and 75% for Mendoza and Cordoba, respectively. The same pattern was found in the number of soil mycorrhizal spores; the average increments for Mendoza and Córdoba were 42% and 121%, respectively. Irrigation treatments did not display any change on the dark septate endophytes rate, but significant differences were observed due to the growing environment (p ≤ 0.01). These results suggest that water uptake by mycorrhizae hyphae and/or increased water uptake related to mycorrhizae changes in root morphology or root fineness could conceivably allow mycorrhizal plants in drying soil to effectively providing roots access to more of the soil water reservoir.