干旱区生态环境知识资源中心

Spergularia diandra is a common annual in the Negev Desert. In one population near Sede Poker nine types of seeds with differing germinability were found. These comprised three genotypes, producing glabrous, hairy or partially hairy seeds. Within each genotype, three coloured phenotypes mature: black, brown and yellow seeds. The plants produce large numbers of tiny seeds which display an opportunistic strategy of low germination percentages which may be regulated by day length and temperature during seed maturation, seed position on the plant and length of storage. This is of great importance for survival of this species, especially in extreme deserts with small unpredictable amounts and distribution of rain. (C) 1996 Academic Press Limited