PT  - JOURNAL ARTICLE
AU  - Percival, Glynn C.
AU  - Percival, Christopher D.
TI  - Evaluation of Heat Tolerance in Foliar Tissue of <em>Acer</em> Genotypes
AID  - 10.48044/jauf.2024.002
DP  - 2024 Mar 01
TA  - Arboriculture & Urban Forestry (AUF)
PG  - 157--168
VI  - 50
IP  - 2
4099  - http://auf.isa-arbor.com/content/50/2/157.short
4100  - http://auf.isa-arbor.com/content/50/2/157.full
AB  - Background Extreme summer heat events in which temperatures exceed 40 °C are expected to increase in duration and intensity worldwide. Consequently, selecting heat-tolerant trees for future predicted climatic conditions will be one of the significant challenges for urban landscape managers.Method The effect of heat stress (44 °C for 4 hours) on chlorophyll variable:maximum fluorescence (Fv/Fm) ratios and Soil Plant Analysis Development (SPAD) values as measures of damage to the leaf photosynthetic system and leaf chlorophyll content was quantified in 8 Acer genotypes (Acer pseudoplatanus ‘Negenia’, A. pseudoplatanus ‘Spaethii’, A. platanoides ‘Royal Red’, A. platanoides ‘Princeton Gold’, A. platanoides ‘Emerald Queen’, A. platanoides ‘Drummondii’, A. campestre, A. campestre ‘Louisa Red Shine’).Results Fv/Fm ratios proved to be a sensitive indicator of heat damage and positively identified marked differences in tolerance to and recovery from heat damage between the 8 Acer genotypes. Estimated leaf chlorophyll content (SPAD) was not sufficiently sensitive to distinguish differences in tolerance and recovery between genotypes.Conclusions Chlorophyll fluorescence Fv/Fm ratios, but not estimated leaf chlorophyll content (SPAD), offers a rapid screening technique for assessing the tolerance to and recovery from heat stress in leaf tissue of trees.