PHYTOTOXIC POTENTIAL OF THE GEOPROPOLIS EXTRACTS OF THE JANDAIRA STINGLESS BEE ( Melipona subnitida ) IN WEEDS

ABSTRACT The objective of the present research is to characterize the phytotoxic activity of geopropolis from the Jandaira bee (Melipona subnitida Ducke) in the state of Ceará in Northeast Brazil and to analyze its effects. Extracts were prepared in 80% v/v grain alcohol at 0.25, 0.5, 0.75, and 1.0%. Their effects were determined on seed germination, radicle elongation, and hypocotyl growth of the pasture weeds malícia (Mimosa pudica) and mata-pasto (Senna obtusifolia). Extract phytotoxicity varied as functions of plant species, application dosage, and plant organ. M. pudica was more sensitive to the inhibitory effects of geopropolis than S. obtusifolia. There was a phytotoxic effect of 50% (PE50) for S. obtusifolia in terms of seed germination and in rootlet development near the maximum applied concentrations. M. pudica had PE50 and PE90 at the minimum concentration (0.25%) and near the maximum (1.00%), respectively. Thus, geopropolis extracts from the Jandaira bee (M. subnitida) are potentially phytotoxic to certain plant species.摘要：本研究旨在表征巴西东北部塞阿拉州詹代拉蜂（Melipona subnitida Ducke）所产地蜂胶（geopropolis）的植物毒性活性，并分析其生物学效应。研究以体积分数80%的谷物乙醇配制了浓度分别为0.25%、0.5%、0.75%及1.0%的提取物。以牧场杂草含羞草（Mimosa pudica）与钝叶决明（Senna obtusifolia）为受试材料，检测该提取物对其种子萌发、胚根伸长及下胚轴生长的影响。地蜂胶提取物的植物毒性随受试植物种类、施用浓度及植物器官的不同而存在差异。相较于钝叶决明，含羞草对地蜂胶提取物的抑制效应更为敏感。在最高施用浓度附近，钝叶决明的种子萌发及幼根发育均达到50%植物毒性效应（PE50）；含羞草的PE50与PE90分别出现在最低施用浓度（0.25%）与接近最高施用浓度（1.00%）的条件下。综上，詹代拉蜂（M. subnitida）所产的地蜂胶提取物对部分植物物种具有潜在植物毒性。