Assessment of germination and vigour status of 24-year-old seeds of a Sophora hybrid

Abstract

Germination and vigour of 24-year-old seeds collected from a single individual of a hybrid Sophora and stored at room temperature are compared with seeds from the 2001 season from the same tree. Germination of machine-cleaned seed showed the hard seed character was still evident after 24 yr. Hand-chipped seeds of the 2001 harvest gave 93% germination; 1977 seeds were 8%. Of the 2001 harvest there was little difference in germination between machine-cleaned seeds and seeds removed by hand from pods. The majority of 1977 embryos were dead within their hard seed coat. Hand-chipped and machine-scarified seeds of both harvests were subjected to two accelerated ageing treatments designed to impose physiological stress. Germination of 1977 seeds was suppressed to zero but 2001 seeds were minimally affected. Tetrazolium tests for viability showed that viability was lost from most 1977 seeds. The loss in germinability and viability of the 1977 seeds was accompanied by a loss in vigour of remaining viable seeds. Leakage of solutes from 1977 seeds was greater than from 2001 seeds, suggesting cell membrane and cytoplasmic damage.