Radial oxygen loss and physical barriers in relation to root tissue age in species with different types of aerenchyma.

Plant root aeration relies on aerenchyma and barrier formation in outer cortex influencing the radial oxygen loss (ROL) from roots towards the rhizosphere. Plant species display large variation in strategies for both responses. We investigated the impacts of root-zone hypoxia on aerenchyma formation and development of ROL apoplastic barriers in the outer cortex as a function of root tissue age using three lowland grassland species, each with alternative aerenchyma structure.

Facilitative effect of Lotustenuis on Paspalumdilatatum in a lowland grassland of Argentina.

We studied the responses in growth and N content of the perennial grass Paspalum dilatatum to the substitution of Lotus tenuis for a whole group of species, the dicotyledons of a natural grassland community, in the Salado lowland Pampas of Argentina. Two kinds of manipulations were performed in the field: removal of alien dicots with herbicide application, and introduction of L. tenuis, resulting in a combination of four treatments, arranged in a 2 × 2 factorial randomized block design.

Effects of flood-influenced factors on seed germination of Ambrosia tenuifolia.

Strong fluctuations are exhibited by populations of the perennial herb Ambrosia tenuifolia in the grasslands of the Salado basin (Province of Buenos Aires, Argentina), an area frequently enduring prolonged floods. Flooding causes the death of most dicotyledon plants of the community, A. tenuifolia among them, opening numerous gaps of various sizes.