Understanding carbon sink-source relationships in seed orchard loblolly pine ramets

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Attributes of shoots and their female reproductive organs from six ramets of a single loblolly pine clone were assessed in 2015 and 2016 at a Louisiana seed orchard. Seasonal developmental patterns were similar between years. Female strobilus buds were visible in December of year 1, and female strobili were pollinated in early March of year 2. Conelets (pollinated female strobili) stopped increasing in length from June of year 2 until March of year 3 when rapid expansion occurred over the next 4 months. In March and April of 2016, 61 percent of female strobili and conelets of the 2017 crop were aborted whereas a few conelets of the 2016 crop were lost. Competition for carbohydrate among various actively growing sinks in the spring may play a critical role in the abortion of female strobili and conelets. Balancing the carbon sink-source relationships among vegetative and reproductive organs should be considered when the goal is to enhance the production and retention of female reproductive organs.

  • Citation:

    Sung, Shi-Jean S.; Sayer, Mary Anne S.; Leduc, Daniel J.; Tule, James; Dougherty, Phil; Muir, Nicholas G. 2018. Understanding carbon sink-source relationships in seed orchard loblolly pine ramets. In: Kirschman, Julia E., comp. Proceedings of the 19th biennial southern silvicultural research conference; 2017 March 14-16; Blacksburg, VA. e-Gen. Tech. Rep. SRS-234. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station: 129-135.

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