Strophiolar Water Conduction in Seeds of the Trifolieae Induced by Action on the Testa at Non-Strophiolar Sites

Abstract

When impermeable legume seeds are made permeable to water by mechanical treatments that make strophioles conductive, it is not known whether the strophioles themselves must be acted on directly. To investigate this question the testas of individual seeds from the genera Medicago, Stylosanthes and Trifolium were either broken through completely by cutting, filing or piercing, or stressed by squeezing or striking, at sites remote from the strophioles. As determined by serial photography, 30-90 % of the previously impermeable seeds became conductive at the strophiole. These results indicate that the strophiole can become conductive without being acted on directly. They also suggest that the strophiole and general testa should be regarded as an integrated system in which both water-repellency and mechanical properties of the testa are important in the control of water absorption.