Phertotypic Plasticity of Seed Germination as a Component of the Complementary Sets of Adaptations and Survival Strategies During the Life Cycle of Ephemerals Occurring in the Negev Desert of Israel

摘要

Many of the ephemeral plant species with unrelated taxa occurring in the Negev Desert (Zohary, 1966, 1972; Feinbrun-Dothan, 1978, 1986) have been found to have developed ecologically equivalent or possibly even convergent (Cloudsley-Thompson, 2001) sets of complementary adaptations and survival strategies throughout the different stages of their life cycles (Gutterman, 1993, 2000, 2002a,b). These include phenotypic plasticity of seed germination (PPSG) influenced during seed development, maturation and storage, seed dispersal and germination (Fig, 43.1). Post-maturation environmental factors affecting PPSG in Australia were found by Quinlivan (1966) and in North America by Went (1953). Seed position influences on PPSG were found to affect the shapeand mucilaginous layer of seeds in the Namaqualand desert of South Africa (Beneke, 1991; Beneke et al., 1992a,b).