Clonagem de faveleira (Cnidoscolus quercifolius Pohl.) por alporquia utilizando rejeito de vermiculita e diferentes concentrações de Ácido Indol Acético.

Abstract

SUMMARY: The drought resistant Cnidoscolus quercifolius (faveleira) is a rustic fast growing tree that can be used to reforestation and restoration of degraded areas. Its products can be used as animal and human food, medicine and biodiesel. Air-layering is an easy cloning technique, recommended for species with poor rooting capacity, and it does not require specific facilities such as greenhouses for seedling production. Many factors affect seedling production by layering, such as the use of rooting inductors and type of substrates. The utilization of mining wastes can be economically and environmentally advantageous, as it can reduce costs of seedling production and mitigate the impacts resulting from waste deposition in the environment. This study evaluated different concentrations of the rooting inducer Indol Acetic Acid (IAA) and the waste of the vermiculite industry on the production of C. quercifolius seedlings by the air-layering technique. The substrate vermiculite was used as control. Data were collected regarding the time necessary for the seedlings to develop roots; at day 90, air-layered seedlings were observed for the presence of callus with root primordia or roots, root number, longest root length (cm), fresh and dry root weight (g), and percentage of rooted seedlings. Most of the seedlings developed the first adventitious roots at day 35. At day 90, 46% and 30% of the seedlings developed roots in vermiculite and control substrates, respectively. Root weight was affected by substrate. Vermiculite waste resulted in higher root weight. This indicates that Vermiculite waste substrate result in significantly higher root weight, producing almost twice as much root biomass. Indol Acetic Acid showed no significant effect on any variable. However, numerically, increments of fresh and dry matter were higher for 8g of IAA / L, while the number of roots peaked for 4.0 g IAA/ L. Except for root dry weight, the use of vermiculite waste showed no significant effect on the studied variables. However, in general, in absolute values, the best results occurred with the use of vermiculite waste. Even if vermiculite waste resulted in similar values, its use as substrate in seedling production would be of great importance, because it is easy and cheap to buy. Also, its use as the substrate or part of it shows to be a viable ecological alternative to reduce the environmental impact caused by the emission and accumulation of this residue in the environment.