ROOT-GROWTH POTENTIAL AND STARCH DIFFERENCES IN SEEDLINGS OF 6 FAMILIES OF GENETICALLY IMPROVED LOBLOLLY-PINE

The relationships among root growth potential, total fresh weight, and starch levels of six genetically improved families of loblolly pine (Pinus taeda L.) were examined during a test of root growth potential, with special focus on clarifying changes in starch concentrations as determined by destructive analysis. Seedlings were operationally grown and root-wrenched in a nursery, lifted in January and subjected to 14 days of cold storage at 3-degrees-C (38-degrees-F), then placed in a tank system in a greenhouse under extended 16-hr days and 30-degrees-16-degrees-C (85-degrees-60-degrees-F) day-night temperatures. Measurements taken over a 30-day period showed that (1) the percentage of starch initially in the roots was not related to root growth potential expression after 30 days, (2) the starch in new white lateral roots after 30 days was not related to root growth potential, and (3) seedlings that produced new roots tended to have more total starch in all plant parts than those that did not.