Plants remember changing temperature
Temperatures are rising. We feel it all ourselves. But how does higher temperature affect plants and, in particular, their offspring?
In two consecutive years, we performed controlled crosses on bird cherry, a native shrub species. In doing so, we applied pollen from one father plant to the pistils in the flowers of several genetically identical mother plants, i.e. clones. After fertilisation, we placed half of these mother plants in a warm greenhouse, the other half in a cold one. Ripened berries were picked on all mother plants and further on grown under completely the same conditions. Thus, the temperature difference concerned only the period of seed ripening on the mother plants.
All these young plants showed the same timing of leaf colouration in autumn. But bud emergence in spring did differ. In the first year, the plants of the warm seed maturation sprouted earlier. In the second and third year, on the contrary, they sprouted later. A warmth treatment on the young plants in the fourth spring increased the distinction in sprouting between the plants of cold and warm seed maturation.
The reaction in the first year was probably an after-effect, possibly because berries ripened faster on the mother plants in the warm condition. The later sprouting in subsequent years, with a stronger differentiation between warm and cold seed maturation in a warmer spring, indicates a memory of the plant of (too) warm seed ripening.
This plant memory requires further research, but does suggest that plants are capable of remembering changing conditions, at least to a certain extent.
Image above: European bird cherry (photo Rollin Verlinde - Vildaphoto)