Abstract
The anatomic structure of roots and culms of two Juncus species with different degrees of salt tolerance was analysed in
plants grown for two months under salt stress (NaCl treatments) and in control, non-treated plants. The aim of the study was
not only to compare the anatomical structures of a halophyte (J. acutus) and a related glycophyte (J. articulatus), but mostly to
assess whether salt stress induced anatomical modifications, by identifying differences between control and treated plants.
Several slight differences have been indeed detected, in terms of endodermis type, development of aerenchyma and extent of
sclerenchyma in perivascular sheaths. The role of Casparian endodermis was here discussed in relation to its complex
implications in controlling salt influx at the root level that is an efficient mechanism involved in halophytes. Aerenchyma is a
common feature found in marshy halophytes, allowing them to survive naturally under flooding conditions; however, when
occurring in non-waterlogged plants, as is the case of this study, it should be regarded as a genetically, constitutive adaptation
rather than an inducible one. Nevertheless, such anatomic modifications should be regarded as mere alterations due to stress
that is, as stress responses and not as truly adaptations to salinity. In this context, the nature of these modifications either
considered as adaptations or damage indicators of salt stress should be further reconsidered.