干旱区生态环境知识资源中心

Seedling establishment of many cactus species appears to be more frequent under canopies of nurse plants, which provide a less stressful microenvironment. Under these nurse plants, nutrient levels in the soil could be higher than in surrounding areas; these higher nutrient levels could promote higher seed germination. Seed burial under nurse plants may occur by seeds falling in the litter or in soil cracks; however, buried seeds are in the dark, which has been shown to inhibit seed germination for some cactus species. We measured germination percentage on nutrient-rich soil from under nurse mesquites and in soil from open spaces, and the effect of seed burial (buried and unburied seeds) on seed germination of three cactus species (Coryphantha durangensis, Peniocereus greggii, and Echinocereus longisetus) that grow under nurse plants in the Chihuahuan Desert. Echinocereus longisetus had very low germination across substrates. Coryphantha durangensis had higher germination on mesquite soil than on poor soil, and its buried seeds had lower germination than seeds on the soil surface. Germination of P. greggii seeds was higher on mesquite soil than on poor soil, and its buried seeds had lower germination than seeds on the soil surface.