Seed Germination Characteristics of Rhus tripartitum (Ucria)‎ Grande and Ziziphus lotus (L.)‎ : Effects of Water Stress

الملخص EN

Ziziphus lotus (L.) Lam.

(Rhamnaceae) and Rhus tripartitum or Sumac (Anacardiaceae) are two indigenous species from arid and semiarid regions of Tunisia, characterized by a severe climate where dry seasons are very long.

The combined action of anthropogenic factors and climate in arid regions caused a gradual threat of plant assets.

In this context, an experimental study of the effects of water stress (0 to −1 MPa) on seeds has identified the water requirements germinal stage of both species.

The results showed that both species were able to germinate at relatively low water potentials.

However, beyond −0.6 MPa, germination was completely inhibited for R.

tripartitum, when it reached for another 50% for Z.

lotus.

Increasing the concentration of PEG6000 progressively inhibited germination in both species.

Only Z.

lotus could be considered tolerant of water stress, because, to −1 MPa, seeds germinated with a rate of 17%.

It resulted in that the species Z.

lotus presented an adaptive capacity to aridity much greater than that observed for R.

tripartitum.