Solid matrix priming to enhance germination of loblolly pine (Pinus taeda) seeds

Experiments were conducted to determine whether solid matrix priming (SMP) enhanced germination of loblolly pine (Pinus taeda L.) seeds. Six solid matrices with suitable properties were tested for their water release characteristics and three had the desired characteristics of high water holding capacity and a small change in water potential for a given change in water content. Among the suitable matrices, Carri-All which is a clay was chosen for further study. SMP with Carri-All improved the rapidity of germination (median germination day) and synchrony (time between 15 and 85% germination) for stratified seeds from five open-pollinated North Carolina and Oklahoma families. Total final germination was only slightly improved by SMP. The most rapid, uniform germination was achieved with 6 d of SMP at 30 to 35% WC (-1.5 to -0.9 MPa); longer treatments and higher WCs resulted in germination during treatment. Seed/matrix ratios (dry weight) from 1:1 to 1:4 were equally effective in stimulating germination. The optimum SMP treatment reduced differences in germination vigor among families. SMP has potential as a tool for nursery managers to increase the rapidity and synchrony of loblolly pine seed germination and produce more uniform and vigorous seedling crops.