Morfoanatomia, perfil químico e atividade alelopática de três espécies de Copaifera L. (Leguminosae Caesalpinioideae) nativas da Amazônia

Abstract

Species belonging lo lhe Copaifera L. genus (Leguminosae) are widely ulilized in lhe Amazonian popular medicine, and ils oils are considered lo be one of lhe more importanl nalural medicines of lhe forest. Despile ils greal importance, lhere are few sludies concerning lhe morphological and analomical characlerislics of lhe genus, especially lhose describing ils reproduclive slruclures. Particularly, lhe laxonomic characlerizalion of lhe Amazonian species of Copaifera deserves more attenlion. This way, lhis sludy aimed lo characlerize lhe morphological aspecls of fruils, seedlings and saplings of Copaifera martii Hayne, C. duckei Dwyer and C. reticu/ata Ducke. The seeds, eophylls and melaphylls morpho-analomy was also sludied, as well as lhe occurrence and dislribulion of melaboliles in lhe seeds of lhese species. Particularly, we aimed lo better describe lhe laxonomic dislinclion between C. duckei and C. reticu/ata, lhe two c10sely relaled Copaifera Amazonian species. The possible allelopalhic effecls of lhe essenlial oil from leaves and slem of lhese species were also verified. The fruil of lhe lhree species are legumes. The exolesla surface, when observed in eleclronic microscopy, showed lo be predominantly punclualed in C. duckei and C. martii, and microreliculale in C. reticu/ata. The colyledons are recovered wilh a Ihin, slightly slrialed culicle in C. duckei, while lhe culicle of lhe olher two species is clearly slrialed. The ouler periclinal wall of lhe epidermis is slightly convex and presenls depressions in C. duckei, being convex in lhe olher two species. The embryonic axis of C. duckei presenls small diameler in relalion lo ils lenglh, while in C. martii and in C. reticu/ata Ihese measures are proportional. C. duckei and C. martii presenls rudimenlary plumule, displaying one and two proluberances in lhe apex, respeclively, bul in C. reticu/ata, lhe plumule is poorly differenlialed, once il presenls leaflels in lhe inilial slages of development. The malure seeds of lhe lhree species presenl phenolic compounds and alkaloids, which are probably lhe main defense subslances of lhe legmen and lhe epidermis of lhe colyledons. Lipids and proleins are lhe main reserve subslances of lhe epidermis and lhe parenchyma of lhe colyledons. The main difference observed among lhe saplings of lhe Ihree species is lhe presence of well-developed, foliaceous slipules in C. reticu/ata, which are absenl in C. duckei and are similar lo Ihose of lhe seedlings in C. martii, being also foliaceous bul less conspicuous. C. martii presenls allernale phyllolaxy, while lhe olher species presenls opposile phyllolaxy. We delecled severa I melaboliles in lhe foliar limb, such as slarch, lipophilic and peclic subslances, and mucilaginous, cryslal and phenolic idioblasls. Eophylls and melaphylls are analomically similar. The Ihree species presenl secrelory cavilies and glands. The allelopalhic aclivily of essenlial oil from slem and leaves of lhe sludied species did nol revealed significanl differences in lhe two species lesled (Mimosa pudica L. e Senna oblusifolia (L.) H.S. Irwin e Barneby). However, essenlial oil from leaves displayed higher polenlial lo inhibil rools (45%) and hypocolyls (74%) development. Addilionally, lhe major consliluenls delecled showed lo be more concenlraled in lhe leaves Ihan in lhe slem, which explains lhe differences observed on lhe effecls' inlensily of lhe oils oblained. Among lhe idenlified consliluenls, only lhe o-candinen and lhe linalol were previously reported lo have allelopalhic aclivi!y, being presenled, in Ihis work, lhe polenlial allelopalhic aclivily of olher compounds. Resulls oblained here conlribule lo lhe characlerizalion of lhe morphological, analomical and hislochemical aspecls of fruils and seeds of Ihree Copaifera species. Also, we described lhe morphological Irails of seedlings and saplings of Ihese species, conlribuling lo lhe laxonomic dislinclion between lhe taxa, especially between C. duckei and C. reticu/ata.