Plant & zo
The science of plants and more
Heat and drought, what now?
Both heat and drought occur more regular, and more often together. They can cause lots of trouble. Like people, plants don’t like it. They get stressed. Especially when there is both heat and drought. Heat and drought are asking for conflicting reactions. When there is just heat, a plant will cool down by evaporation, like sweating. While by drought, it will want to keep all the water inside. But, add heat, and the temperature goes up. Causing trouble. What to do?
American researchers deciphered how the plant handles this. Studying soybeans and tobacco, the researchers looked at what happens during heat and drought. The first thing they noticed was the higher temperature of the leaves and flowers during heat or a combination of heat and drought. But this was the only similarity in the reaction on heat or heat and drought.
Silencing of the drought-manager gives plant reproduction a chance
By heat the plant open the stomata, pores, wide open in the leaves and flowers. While when there is both heat and drought, then the plant keeps in the leaves its stomata closed. But not those in the flowers. These are open. Cooling the flowers, so it appears. When the researchers closed of the stomata using Vaseline, the temperature in the flowers increased. Suggesting that the plant tries to cool down the flowers as much as possible, even if it costs precious water.
The drought-manager ABA causes stomata closure by drought. But in flowers, so shows this study, the heat-manager causes breakdown of ABA. Silencing ABA in its job to close the stomata. The intervention of the heat-manager helps protecting the flowers against high temperatures. It gives fertilization a chance.
By a combination of heat and drought, plants need to make a choice in what to protect and to which cost. Protecting precious flowers, the reproduction organs, comes before the protection of replaceable leaves. The silencing of the drought-manager gives plant reproduction a chance.
Sinha, R., Zandalinas, S.I., Fichman, Y., Sen, S., Zeng, S., Gómez-Cadenas, A., Joshi, T., Fritschi, F.B. and Mittler, R. (2022), Differential regulation of flower transpiration during abiotic stress in annual plants. New Phytol, 235: 611-629. https://doi.org/10.1111/nph.18162