Onion seed anatomy in relation to aging

Abstract

The seed coat functions to protect the embryo from adverse environmental conditions. Scanning electron microscopy (SEM) studies were conducted to reveal the fine details of the seed coal surface and internal structure of ten cultivars of onion. SEM observations showed that seed coat shrinkage and cracks existed in all cultivars. Cracks were more pronounced near the hilum area. The largest part of the elongated embryo was located immediately underneath the cracked seed coat except for the distal part of the cotyledon. Fungal infection was observed in seeds especially near the Mum and seed cracks. It was found that seed coat structure, embryo position, and seed coat microflora are factors in loss of viability in onion seed. © 1995 Taylor & Francis Group, LLC.