Influnce of salinity on mitotic division and chromosomal behaviour of some taxa of zygophyllum

الملخص EN

The present investigation deals with the effect of salinity (NaCl) on seed germination, mitotic division and chromosomal behavior of some taxa of Zygophyllum naturally growing in the Egyptian deserts.

These species are Z.

simplex, Z.decumbens Z.coccineum, Z.aegyptium, Z.

album, Z.berenicense and Z.

propinquum.

The applied concentrations of NaCl were 31, 62, 125, 250, 350, and 500 mM.

The results indicated that the seeds of different taxa showed different percentages of germination under normal conditions.

The highest percentages were recorded with Z.

simplex and Z.

coccineum, whereas, the lowest percentages of germination were recorded with seeds of both varieties of Z.

decumbens.

For all studied species, the germination percentage decreased with increasing the NaCl concentration.

Moreover, no germinated seeds were recorded at 350 mM and 500 mM for all the studied taxa.

The results also revealed that all the studied taxa have Mitotic index (MI) values less than 6 %, where the MI values ranged from 5.93 to 4.20 and which recorded in Z.

album and Z.berenicense, respectively.

Under salt stress, the mitotic values sharply decreased with the increase of NaCl concentration and the lowest value of 0.04 % was recorded following treating the root tip cell of Z.

coccineum with 250 mM.

In the treated roots, the inhibition of the mitotic division was accompanied with imbalance in the frequencies of the mitotic stages.

At higher concentrations of NaCl, the decreases in MI value are associated with the induction of chromosomal abnormalities in all studied taxa of Zygophyllum.

The percentage of the total abnormalities was increased with the increase of NaCl concentrations.

The treatment induced different types of chromosomal aberrations and the chromosomal stickiness was the most common type of abnormality in all taxa.