Effect of Available Soil Calcium on Taproot Elongation of Loblolly Pine (Pinus taeda L.) Seedlings1
- E. S. Lyle and
- Fred Adams2
Three vertical split-root experiments were performed to discover a method of describing Ca availability in soils that could be correlated with taproot elongation of loblolly pine seedlings and could be used to determine critical values at which elongation rate became inhibited.
The first experiment, utilizing a vertical split-root technique with a fertile topsoil overlying nutrient solutions, proved that loblolly pine roots will elongate in an ambient solution of CaCl2 and deionized water. However, elongation was much greater when other ions were also present in the ambient solution. The second and third experiments also utilized a vertical split-root technique but the subsurface medium was an infertile loamy sand with varying amounts of Ca, Mg, K and NH4 salts added. It was found that aCa/aMg, MCa/MMg, and aCa/Σacation i ratios of soil solutions showed a close relationship with tap-root elongation, and the relationship was continuous from extreme Ca deficiency to Ca sufficiency. The data show that tap-root elongation was inhibited when MCa/MMg, aCa/aMg, and aCa/Σacation i ratios fell below 0.75, 0.75 and 0.10, respectively.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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