Publicação on-line; 18 ref.; 1 table; 22 illus.; Summaries (En, Pt)

RESUMO:

Folhas de Glycine max (L.) Merril, infectadas pelo fungo Phakopsora pachyrhizi H.
Sydow & Sydow e tratadas com extratos vegetais foram avaliadas, visando determinar in vivo as
modificações anatômicas nas diferentes estruturas/tecidos foliares, além de reconhecer prováveis
mecanismos de defesa. Folhas de soja cultivar 181 provenientes do quinto nó foram inoculadas
com fungo e tratadas com diferentes extratos vegetais, água e álcool 70%. Para comparação
foram analisadas a anatomia das folhas sadia e infectada e realizadas medidas nas estruturas/
tecidos foliares. Na folha infectada, observou-se destruição da epiderme e parênquima lacunoso,
visível proliferação de tricomas e cutícula espessada, principalmente na face abaxial. Observouse
a presença de compostos fenólicos nas células da epiderme quando rompida, em função do
crescimento micelial. Nas folhas infectadas e tratadas com os extratos vegetais de Azadirachta
indica, Maytenus ilicifolia e Allium sativum, as estruturas/tecidos vegetais apresentaram aumento
de espessura por alongamento celular.

Palavras-chave: ferrugem da soja, ferrugem asiática, urediósporos, fungos, Glycine max

ABSTRACT.

Leaf anatomy of soybean infected with Phakopsora pachyrhizi H. Sydow &
Sydow and treated with plant extracts. Glycine max (L.) Merril leaves, infected by the fungus
Phakopsora pachyrhizi H. Sydow & Sydow and treated with plant extracts, were evaluated with
the aim of determining in vivo the anatomical modifications in different leaf structures and of
identifying probable defense mechanisms. Leaves from the 181 soybean cultivar originated from
the fifth node were inoculated with the fungus and treated with different plant extracts, water and
alcohol at 70%. For comparison, the anatomy of the healthy and infected leaves was analyzed
and the leaf structures were measured. In the infected leaf, there was destruction of the epidermis
and lacunar parenchyma, apparent trichome proliferation and denser cuticle, especially on the
abaxial surface. There were also phenolic compounds in ruptured epidermis cells, due to mycelium
growth. In the infected leaves treated with Azadirachta indica, Maytenus ilicifolia and Allium sativum
extracts, the plant tissues had an increase in thickness due to cell elongation.

Key words: soybean rust, Asiatic soybean rust, urediniospores, fungi, Glycine max