Defesas foliares em resposta à herbivoria em espécies lenhosas de restinga,Ipojuca-PE

Abstract

The leaf, the major photosynthetic plant organ, has the important function to adjust the plants to different habitats through morphological, chemical and physiological changes as a defense against the environmental factors. The chewing insects, the major consumers of leaf tissues, prejudice the behavior of the plants through the consumption of the photosynthetic tissue. Some plants survive developing chemical and structural strategies of defense. This study evaluated the anatomical and chemical characteristics of defense in plants responsible to the acceptability or resistance to the herbivorous chewing insects in leaves, young and mature, in individuals of species occurring in restinga vegetation. The studied species were: Andira fraxinifolia Benth. (Fabaceae), Annona crassiflora Mart. (Annonaceae), Casearia javitensis Kunth (Flacourtiaceae), Guettarda platypoda DC. (Rubiaceae), Hancornia speciosa Gomes (Apocynaceae), Marlierea cf. regeliana (Myrtaceae), Myrcia bergiana O. Berg.(Myrtaceae), Ouratea fieldingiana (Gardner) Engl. (Ochnaceae), Sacoglottis mattogrossensis Malme (Humiriaceae) e Tetracera breyniana Schlechtd (Dilleniaceae). Ten young and ten mature leaves from five indivuals of each species were collected. All leaves were digitized in scanner and after fiexd in FAA 50. The phytochemical tests and the histological slides were made following the respective methods. The anatomical analyses were made using an optical microscope and a program of image analysis. Ouratea fieldingiana showed higher values to thickness of cuticle and epiderm, comparing with other studied species. However, Annona crassiflora exhibit greater leaf thickness and it was the third specie less attacked by herbivores. The species H. speciosa and S. matogrossensis showed smaller leaf lamina taken off by herbivorous, probably as a response to the presence of latex and rutine, indicating a chemical defense. The anatomical characters and the herbivory percentage showed a negative correlation without significance. However, the phytochemical and anatomical analysis exhibited a great variety of defensive strategies, as a positive result to the major secondary compounds classes (alkaloids, phenolic metabolites, and saponosides) and anatomical characters (cuticle and epidermal thickness, presence of trichomes, crystals and schlerenchymatic tissues).