Ovule gall stimulating a big fake fruit on Miconia chamissois Naudin (Melastomataceae): a structural overview

Abstract

Galls are an extremely close relationship between plants and some other organism, the galler. This organism is capable of induced a lot of morphological changes in the induced organ. The galler can bring harm to the plant in the common way that is to relocating substances of the plant for their benefit or may impact the reproduction of the plant too. For to directly affect the reproduction of the host plant it is necessary for the gall to occur in a reproductive organ and end up preventing or reducing the seed dispersal. Our main objective was to evaluate if the galler Allorhogas uberlandiensis negatively affects reproductive rate in a floral bud galled in the plant Miconia chamissois. The news tissues formed by gall induction were also observed in comparison with their original tissues, in addition to the compounds accumulated in them. The “fruit-like gall” (whole structure induced by galler) volume is on average 5.4 times larger than mature fruits (these being the largest reproductive structure of the host plant) and galls are on average 20 times larger than the ovules. In the gall a typical nutritive tissue and a reserve tissue are formed. Occurs the accumulation of lipids, proteins and pectins. With the anatomical analysis it is possible to observe that the induction of gall ends up creating a physical barrier that obstructs the reproductive structures from connecting to the outside, which is essential for fertilization to occur. Thus, it is possible to infer that 100% of the ovule present in a galled floral bud become unviable. As the galler has a significant impact on floral buds reducing the reproduction rate of the host plant, in this system the galler can be considered a pest or a biological control agent according with the status of Miconia chamissois in the location (as a native or invasive plant).