Supraoptimal Root-Zone Temperature Alters Growth and Photosynthesis of Holly and Elm    (View PDF)

Chris A. Martin, Dewayne L. Ingram and Terril A. Nell

Abstract: Effects of root-zone temperatures (28°, 35° and 42°C; 6 hrs/day for 12 weeks) on container-grown 'East Palatka' holly (Ilex x attenuata 'East Palatka') and 'Drake' elm (Ulmus parvifolia 'Drake') were determined under growth-room conditions. Survival rate of elm was decreased by 50% after 12 weeks of daily exposure to 42°C. Temperature did not affect shoot to root ratios of either genus. However, dry weights of holly shoots and roots and elm roots decreased quadratically, and elm shoots decreased linearly with increased temperature. Time trend analysis for holly and elm shoot extension, leaf carbon exchange rates (CER), and stomatal conductance (Cs) revealed reductions at 42 °C compared to 35° and 28 °C for both genera. Results demonstrate the need for tree growers to execute cultural practices directed at minimizing exposure of tree roots to temperatures at or above 42°C.

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https://doi.org/10.48044/jauf.1989.058