Anatomy and metabolite content of high relative humidity-induced adventitious roots in tomato (Solanum lycopersicum L.)

REVOLLAR OCHATOMA, PAMELA; MIGNOLLI, FRANCESCO; VIDOZ, MARÍA LAURA

Congreso; XXXIV Reunión Argentina de Fisiología Vegetal; 2023

Many environmental and endogenous factors, such as light, temperature and mineral nutrition, affect the development of adventitious roots (ARs). In addition to their economic and ecological importance, developing ARs in response to biotic and abiotic stress is crucial for plant survival, especially when the primary root system dies. High atmospheric humidity (HH) can trigger AR formation in tomato plants (Solanum lycopersicum L.), involving conspicuous anatomical and metabolic changes. For this reason, we investigated the anatomy and the content of sugars and amino acids of ARs that developed in HH compared with those formed under flooding conditions. Tomato plants of the Ailsa Craig cultivar were grown in 300 cm3 plastic pots in a growth chamber. When plants were four weeks old, they were placed individually in 1-L plastic containers. The edge of the container was sealed with a gas-permeable plastic film to maintain HH around plant stemswithout limiting gas exchange. Flooding was applied by submerging plant stems with water up to cotyledons. ARs formed under HH displayed higher soluble sugars (sucrose, glucose and fructose) and starch content, whereas the concentration of amino acids was similar in both types of ARs. Anatomically, ARs in HH presented a more compact cortex with expanded and isodiametric cells, while ARs from flooded plants were characterised by air spaces due to aerenchyma formation. These results indicate that ARs are differentially regulated in response to the factor that induces them and that tomato plant stems can distinguish the water potential of the external environment, resulting in the formation of either flooding or HH ARs.