Abscisic acid and biomass partitioning in tomato under salinity

Increasing soil salinization is an enormous cause of crop productivity reduction in many areas of the world. It has a deep backlash on crop yields because it reduces leaf growth and induces leaf senescence, this in turn reduces plant assimilation activity, impairing its capacity for producing further growth or harvestable biomass. Plant has the capacity for adaptation to the environmental conditions likely involving long-distance signals between different organs (e.g., between root and shoot) through phytohormones. Abscisic acid (ABA) between them, surely, has an important action in the whole plant responses to drought and salt stresses. Processes that control leaf growth and shoot development during the osmotic phase of salinity are still not well known and several different opinions exist on cross-talk between other hormones and ABA in the process of biomass allocation under salinity conditions. Moreover root system likely plays an important role to cope up with salts, and how salts affect root growth and architecture is of great importance to understand plant adaptation process to this abiotic stress. Root architecture modification under salinity seems to be a crucial aspect of crop response to salinity on which significance there are still many aspect to clarify. Our experimental activity suggests that the amount of ABA and ion increase in tomato leaves significantly regulates both growth and gas exchange in tomato. ABA seems to be involved in tomato salt response and could have a crucial action in regulation of dry matter partition between root and shoot of tomato plants subjected to salinity. The significance of root architecture in tomato processes to salt adaptation is still uncertain, but it likely plays an important role. Source–sink control and root-to-shoot signaling are interconnected mechanisms that allow tomato plants to increase salt tolerance.