Xóchitl Damián, Juan Fornoni, César A. Domínguez and Karina Boege
Plants have to deal with simultaneous physiological and environmental challenges, from growing and defending their tissues from consumers, to reproducing and dispersing. Hence, plants need to optimize the use of resources for these different functions. In the case of leaves, for example, plants express different characters to photosynthesise and assimilate carbon into their tissues, and eventually grow. However, they need to protect these tissues from the animals, fungi and bacteria that feed on them by producing chemicals, spines or other defensive characters. So, the simultaneous expression of both growth and defensive traits can be quite challenging if these different functions compete for resources. In addition, as plants develop, their physiological priorities change. For example, whereas young plants may have the priority to grow, older plants need to store resources for further reproduction. In this work, we investigated if the coordinated expression of leaf traits related to growth and defence changes during the development of plants. We show that the expression of growth and defensive traits is not tightly linked in young plants. In other words, they can be expressed independently from each other. In contrast, when plants start reproducing, the expression of these traits is conditioned by their genetic correlations. These differences seem to be independent of changes in plant size, but related to other processes intrinsic to the development of plants. This information is useful to understand the limitations that plants face to express different characteristics. In particular, we learned that the expression, and probably the evolution, of growth and defence- related traits is influenced by plant development.
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