Effect of gamma radiation on the morphology and Thermophysical properties of the pollen wall of Phoenix dactylifera L.

Abstract

Pollen grains of Phoenix dactylifera were exposed to different doses of gamma radiation (250,500,1000 rad and 1 M rad). To access the effect of radiation on the external morphology of the pollen grains, they were examined with SEM after each treatment. In addition the differential thermal analysis technique was used to elucidate the stability of the chemical composition of the pollen wall to gamma radiation. A portion of the treated pollen was- used to pollinate different inflorescences of two female palm trees. The pollen grains that were exposed to y -radiation doses of 250,500 rad were morphologically similar, but showed differences in thermal behaviour. Pollination with these pollen grains resulted in setting fruits that were large in size compared with those developed after pollination with untreated pollen or pollen grains radiated with 1000 rador 1 M rad. The treatment with 1000 rad induced in the morphology of the pollen, and increasing of the thermal resistance of the pollen wall. The 1 M rad dose caused obvious damage and collapse of the pollen wall. Thermophysical properties of various doses treated palm pollen indicate that materials of different layers of pollen wall are not homogenous.