Climate change is increasing the frequency and intensity of drought in the western USA. Evidence suggests that drought preconditioning of plants may improve the survival of planted seedlings under dry conditions through enhanced water uptake by roots, but the mechanisms underlying enhanced survival under drought remain unknown. We tested whether the vertical distribution of roots in root plug cross-sections varied with drought preconditioning and seed source. We subjected western larch (Larix occidentalis Nutt.) seedlings from eight different provenances to Low (50-65% gravimetric water content), Moderate (65-75%), and High (≥75%) watering regimes in a nursery. We then investigated dry root mass across four root-plug sections, including the taproot and three lateral root cross-sections (top 1/3rd, middle 1/3rd, and bottom 1/3rd of root plugs). We also tested for carry-over effect of drought preconditioning on the mass of egressed roots observed among cross-sections of potting soil in a 30-day potted study. Root plug mass varied significantly (P< 0.001) with watering regime, root plug cross-section, and an interaction between watering regime and cross-section. Overall, seedlings that received less water produced lateral root plug cross-sections of greater mass, which coincided with taproots of less mass. In contrast to findings from the root plug study, the distribution of egressed root mass among cross-sections of potting soil did not vary with drought preconditioning. This is the first study to assess seedling root growth in response to drought preconditioning in western larch with a focus on the distribution of root mass in root plugs and egressed root mass among soil cross-sections. We expect this work to facilitate future efforts to improve drought hardiness of western larch seedlings. Future improvement of western larch seedlings will require investigation into whether altered root plug mass distribution translates to improved seedling performance in outplanting trials.
Assessment, N. C., & States, U. (2018). National Oceanic Atmospheric Administration: Vol. II.
Atzmon, N., Moshe, Y., & Schiller, G. (2004). Ecophysiological response to severe drought in Pinus halepensis Mill. trees of two provenances. Plant Ecology, 171(1–2), 15–22. https://doi.org/10.1023/B:VEGE.0000029371.44518.38
Burdett, A. N. (1990). Physiological processes in plantation establishment and the development of specifications for forest planting stock. Canadian Journal of Forest Research, 20(4), 415–427. https://doi.org/10.1139/x90-059
Carvalho, A., Pavia, I., Fernandes, C., Pires, J., Correia, C., Bacelar, E., Moutinho-Pereira, J., Gaspar, M. J., Bento, J., Silva, M. E., Lousada, J. L., & Lima-Brito, J. (2017). Differential physiological and genetic responses of five European Scots pine provenances to induced water stress. Journal of Plant Physiology, 215, 100–109. https://doi.org/10.1016/j.jplph.2017.05.027
Clark, J. S., Iverson, L., Woodall, C. W., Allen, C. D., Bell, D. M., Bragg, D. C., D’Amato, A. W., Davis, F. W., Hersh, M. H., Ibanez, I., Jackson, S. T., Matthews, S., Pederson, N., Peters, M., Schwartz, M. W., Waring, K. M., & Zimmermann, N. E. (2016). The impacts of increasing drought on forest dynamics, structure, and biodiversity in the United States. Global Change Biology, 22(7), 2329–2352. https://doi.org/10.1111/gcb.13160
Day, R. J., & MacGillivray, G. R. (1975a). Root Regeneration of Fall-Lifted White Spruce Nursery Stock in Relation to Soil Moisture Content. The Forestry Chronicle, 51(5), 196–199. https://doi.org/10.5558/tfc51196-5
Day, R. J., & MacGillivray, G. R. (1975b). Root Regeneration of Fall-Lifted White Spruce Nursery Stock in Relation to Soil Moisture Content. The Forestry Chronicle, 51(5), 196–199. https://doi.org/10.5558/tfc51196-5
Douma, J. C., & Weedon, J. T. (2019). Analysing continuous proportions in ecology and evolution: A practical introduction to beta and Dirichlet regression. Methods in Ecology and Evolution, 10(9), 1412–1430. https://doi.org/10.1111/2041-210X.13234
Driessche, R. van den. (1992). Changes in drought resistance and root growth capacity of container seedlings in response to nursery drought, nitrogen, and potassium treatments. Canadian Journal of Forest Research, 22(5), 740–749. https://doi.org/10.1139/x92-100
Fettig, C. J., Reid, M. L., Bentz, B. J., Sevanto, S., Spittlehouse, D. L., & Wang, T. (2013). Changing Climates, Changing Forests: A Western North American Perspective. Journal of Forestry, 111(3), 214–228. https://doi.org/10.5849/jof.12-085
Garrity, D. P., Sullivan, C. Y., & Watts, D. G. (1983). Moisture Deficits and Grain Sorghum Performance: Drought Stress Conditioning1. Agronomy Journal, 75(6), 997–1004. https://doi.org/10.2134/agronj1983.00021962007500060031x
Grossnickle, S. C. (2005). Importance of root growth in overcoming planting stress. New Forests, 30(2–3), 273–294. https://doi.org/10.1007/s11056-004-8303-2
Guarnaschelli, A. B., Lemcoff, J. H., Prystupa, P., & Basci, S. O. (2003). Responses to drought preconditioning in Eucalyptus globulus Labill. provenances. Trees - Structure and Function, 17(6), 501–509. https://doi.org/10.1007/s00468-003-0264-0
Karl, T. R., Melillo, J. M., & Peterson. (2009). Global Climate Change Impacts in the United States: a state of knowledge report from the U.S. In Global Change Research Program.
Moler, E. R. V., & Nelson, A. S. (n.d.). Perspectives on Drought Preconditioning Treatments With a Case Study Using Western Larch. Frontiers in Plant Science, 12. https://doi.org/10.3389/fpls.2021.741027
Moreno, R. (2000). New Stocktypes and Advances in the Container Industry: A Grower’s Perspective. Advances and Challenges in Forest Regeneration Conference Proceedings.
Nicotra, A. B., Atkin, O. K., Bonser, S. P., Davidson, A. M., Finnegan, E. J., Mathesius, U., Poot, P., Purugganan, M. D., Richards, C. L., Valladares, F., & van Kleunen, M. (2010). Plant phenotypic plasticity in a changing climate. Trends in Plant Science, 15(12), 684–692. https://doi.org/10.1016/j.tplants.2010.09.008
P.S.U. (2021). STAT 504 - Analysis of Discrete Data.
Semerci, A., Semerci, H., Çalişkan, B., Çiçek, N., Ekmekçi, Y., & Mencuccini, M. (2017). Morphological and physiological responses to drought stress of European provenances of Scots pine. European Journal of Forest Research, 136(1), 91–104. https://doi.org/10.1007/s10342-016-1011-6
Sloan, J. L., Burney, O. T., & Pinto, J. R. (n.d.). Drought-Conditioning of Quaking Aspen (Populus tremuloides Michx.) Seedlings During Nursery Production Modifies Seedling Anatomy and Physiology. Frontiers in Plant Science, 11. https://doi.org/10.3389/fpls.2020.557894
Valliere, J. M., Zhang, J., Sharifi, M. R., & Rundel, P. W. (2019). Can we condition native plants to increase drought tolerance and improve restoration success? Ecological Applications, 29(3). https://doi.org/10.1002/eap.1863
Walter, J., Jentsch, A., Beierkuhnlein, C., & Kreyling, J. (2013). Ecological stress memory and cross stress tolerance in plants in the face of climate extremes. Environmental and Experimental Botany, 94, 3–8. https://doi.org/10.1016/j.envexpbot.2012.02.009
Wang, T., Hamann, A., Spittlehouse, D., & Carroll, C. (n.d.). Locally Downscaled and Spatially Customizable Climate Data for Historical and Future Periods for North America. PLOS ONE, 11(6), e0156720. https://doi.org/10.1371/journal.pone.0156720
Yakovlev, I. A., Asante, D. K. A., Fossdal, C. G., Junttila, O., & Johnsen, Ø. (2011). Differential gene expression related to an epigenetic memory affecting climatic adaptation in Norway spruce. Plant Science, 180(1), 132–139. https://doi.org/10.1016/j.plantsci.2010.07.004
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