CHARACTERIZATION OF THE ARUM-TYPE MYCORRHIZA IN CITRUS MACROPHYLLA WESTER ROOTSTOCK UNDER SALT STRESS
Arum and Paris types are the two major morphological classes of arbuscular mycorrhizal (AM) symbiosis which differ in their fungal structures. AM symbiosis is thought to increase host resistance to salinity stress, a characteristic that could be interesting in areas where the scarcity of irrigation waters forces growers to use low-quality irrigation water. The type of AM colonization was analyzed to ascertain whether it is influenced by saline conditions. Seedlings of Citrus macrophylla Wester (CM) were inoculated with a mixture of two AM fungi. Ninety-six days after inoculation, plants were irrigated with Hoagland modificated solution containing 0, 20, 40, 60 or 80 mM NaCl. CM showed an Arum-type mycorrhiza. Epidermical cells were never colonized and, the infection developed longitudinally and radially in the cortex of the root by many intercellular hyphae. Branches from intercellular longitudinal hyphae gave rise to arbuscules in the cells. These arbuscules were scattered through the cells of the medium and inner cortex, with the outer cortical cell layers relatively free of intracellular fungal structures. The vesicles were also located in the intercellular spaces of the same cortical cell layers. Most of the mycorrhizal roots in the salt treatments showed a higher number of vesicles than the mycorrhizal roots without salt treatment. Under salinity stress, no differences were observed in the mycorrhizal colonization percentages. This could explain the increasing tolerance of mycorrhizal plants observed towards high levels of salinity.
Manuel Rodríguez-Morán, , Josefa M. Navarro, and Asunción Morte, (2015). CHARACTERIZATION OF THE ARUM-TYPE MYCORRHIZA IN CITRUS MACROPHYLLA WESTER ROOTSTOCK UNDER SALT STRESS. Acta Hortic. 1065, 1343-1350
alemow, Arum, salinity, Glomus, structural development