STUDY OF HIGH TEMPERATURE EFFECT ON CHESTNUT SEEDLINGS GROWTH

‘Judia’ variety progenies were put to grow under 25°C and 35°C in order to evaluate their adaptative capacity.
Therefore, two groups of chestnut seedlings grew at control temperature (25°C) during 90 days.
After this period group T₃₅ was placed at 35°C for more 60 days, while the group T₂₅ was maintained at 25°C. Temperature curves (20-36°C) to evaluate photosynthetic rate were made at two different periods, 90 and 150 days.
In the 1^st period no significant differences were observed between groups, being maximal rate measured at 32.5°C (T₁₀₀). Concerning the 2^nd period, group T₂₅ showed that T₁₀₀ decreased to 30°C while in group T₃₅, T₁₀₀ no changes were observed.
Nevertheless, in group T₃₅ a significant reduction in the maximal photosynthetic rate was observed (33%) as well as a significant increase of the Chl a/b ratio (3.15 to 3.37). Concerning the membrane potential (2^nd period), in group T₂₅, a maximal value was obtained between 19-20°C range while in the other group the temperature increased 2°C. We also evaluate the activities of superoxide dismutase (SOD) and catalase (CAT). SOD activity was significantly stimulated at 35°C (14%), whereas CAT did not show any significant alteration between groups.
In relation to the lipid content we observed that plants grown at the higher temperature (35°C) show an increased percentage of saturated fatty acids.

I European Congress on Chestnut – Castanea 2009

J. Gomes-Laranjo, E.J. Gonçalo, F. Peixoto

Castanea sativa Mill., chloroplast activity, gas exchanges, heat stress, photosynthesis, water relations

https://doi.org/10.17660/ActaHortic.2010.866.32