THE EFFECT OF SALINITY STRESS ON GERMINATION AND GROWTH CHARACTERISTICS OF HALOXYLON APHYLLUM AND HALOTHAMNUS SUBAPHYLLUS

Abstract

Knowing the adaptation of plant species used in rangeland planning of various areas concerning drought and salinity stresses could prove effective in enhancing the success of rangeland restoration plans. The study was conducted to examine the salinity resistance in Haloxylon aphyllum and Halothamnus subaphyllus at the germination stage and the effect of various levels of soil salinity on the growth characteristics of these two plants in vitro and research greenhouse of the Birjand University of agriculture faculty as a completely randomized design. Experimental treatments were five salinity levels (0, 3, 10, 20, and 50 Mmhos/cm) in germination and four salinity levels (3, 10, 20, and 50 Mmhos/cm) in a greenhouse experiment with four replications in both. The results showed no significant differences between 3 and 10 Mmhos/cm salinities in terms of the effect on growth characteristics of Haloxylon aphyllum, but the Traits examined for 20 Mmhos/cm salinity significantly reduced. There was a difference in the salinity level of Halothamnus subaphyllus in terms of the effect on its growth characteristics so that the increase in salinity from 3 to 10 Mmhos/cm significantly reduced all measured traits. However, there were no significant differences between the salinity of 10 and 20 Mmhos/cm. None of the plants could grow at a salinity of 50 Mmhos/cm. The results of the germination test showed that the increase in salinity decreased germination indices in both plant species: Haloxylon aphyllum and Halothamnus subaphyllus. A significant decrease was seen in seed germination percentage in Haloxylon aphyllum with an increase in salinity from 20 to 50 Mmhos/cm and in Halothamnus subaphyllus with an increase in salinity to 20 Mmhos/cm. Moreover, the results indicated that salinity has a significant effect on all growth characteristics (fresh and dry weight of radicle and shoot and radicle and shoot length) of Haloxylon aphyllum and Halothamnus subaphyllus