Mutagenic Effects of Sodium Azide and Fast Neutron Irradiation on the Cytological Parameters of M2 Lagos Spinach (Celosia argentea var cristata L.)

Abstract

The effects of fast neutron irradiation (FNI) and sodium azide (SA) on the pollen and cytological parameters of Celosia argentea was carried out. M1 seeds of treated C. argentea plant with fast neutron and sodium azide were collected from the seed bank of Department of Biological Sciences, Federal University of Technology, Minna, Nigeria and raised on the field to maturity stage. Young flower buds were collected from the plants for cytological studies. Cytological analysis of the plants revealed heterogeneous size of pollen grains, with three distinct variant of 29.12, 34.31 and 39.21 μm. The least average pollen diameters (32.66 μm) was recorded in 6.00 mM SA and the highest (37.58 μm) in 4.00 μS FNI. Significant variation (p≥0.05) in the numbers of pollen production per flower and anther were obtained. Lower percentage pollen fertilities were recorded in all the treated plants when compared with the control (94.15 %). However, these values were insignificance (p≤0.05), except for 8.00 mM which had the least of percentage pollen fertility of 71.62 %. The phenomenon of pollen restitution caused by abnormal meiotic division resulted in the formation of dyad, triad and tetrad in higher irradiated doses plants. Cytological analysis of the plant indicated that 8.00 μS had the highest mitotic index with metaphase (56.56) being the most frequent stage followed by telophase (28.40). Meiotic chromosomal counts revealed n = 18 at metaphase, with the formation of dyad and tetrad in most of the treated plants and the control. Abnormal meiotic division in 4.00 mM and 12.00 μS resulted in triad division. Observation from this study therefore, revealed that pollen restitution coupled with high mitotic index in 8 μS confer greater reproductive advantages to the plant.