Digger Pine Seedling Response to Serpentinite and Non‐Serpentinite Soil

Abstract

Seedlings were grown from 17 seed samples collected throughout the natural range of Pinus sabiniana in California. Five collections came from soils derived from ultra—basic serpentinized rock. The seedlings were grown in a greenhouse in cans filled with two different soils. One series of 36 seedlings per sample grew in a fertile, loamy sand forest soil. This planting was replicated in a sterile, highly serpentinized soil gathered at one seed collection site. Significant differences in shoot and root growth were found between populations within each soil treatment. But the relative ranking of populations was similar in both cases. On both soils populations of non—serpentinite origin made the most vigorous growth. Seedlings from the serpentinite soil collection locality made relatively poor growth in the serpentinite soil. No adaptation to the serpentinite soil conditions by populations which came from serpentinite areas was suggested. All seedlings populations appeared to have a high tolerance for extreme serpentinite conditions. The correlation between mean seed size and mean seedling size was low (r = 0.24) in the fertile soil, but much higher (r = 0.68) in the serpentine soil.