Seed Coat Structure Traits of Cycas revoluta Thunb.

Anatomy of the Cycas revoluta seed coat showed that the episperm included sarcotesta,mesotesta and endotesta layers.The sarcotesta layer contained horny epidermis cells,parenchyma cells,as well as a few cells with thickened walls and idioblasts,resin canals,air chambers,and four big vascular bundles.The mesotesta was comprised of sclereids and lignified fiber,with a suture at one end and three holes at the other end.The endotesta had layers of wizened parenchyma cells and veining vascular bundles,and an elliptic membrane preserving its micropyle.Obvious differences were observed between the vascular bundles of the sarcotesta and endotesta.The vascular bundles of sarcotesta appeared to move in an arc along the seed from the hilum side down to the micropyle side.The vascular bundles of endotesta formed the veining net.There were a variety of vessels in both.