RELATION OF RHEOLOGICAL PROPERTIES OF TESTA OF PISUM SATIVUM L. TO HISTOLOGICAL CHANGES

The study was undertaken to determine histological distortions occurring in the pea testa (skin) as a result of various force applications. Multi-directional compression caused bending of macrosclereids and flattening of osteosclereids. Unidirectional pressure caused similar deformations plus eventual separation between cells; shearing caused bending, buckling and wedging of macrosclereids; bruising resulted in cracks between macrosclereids and buckling. The existence of a pentosan-cellulose complex in the basal and apical ends of the macrosclereids and in the end wall regions of the osteosclereids, as established by R. M. Reeve of the U.S.D. A., and the triangular arrangement of the osteosclereids might explain the ability of the macrosclereids to bend and buckle and of the osteosclereids to spread in the end wall regions. This in turn contributes to the resiliency and toughness of the testa in the face of varied physical forces.