Karl Arens, German-born Brazilian plant physiologist and ecologist (Munsterschwarzach, Bayern 01 January 1902 – São Carlos, São Paulo State 1981)

ACHIEVEMENTS

Observed that substances loss through cuticle was a generalized phenomenon in plants

Die kutikuläre exkretion der laubblatter. Jahrb. Wiss. Bot. 80:284-300, 1934

Developed a new method for direct determination of osmotic pressure in a plant cell with a gauge

Um novo methodo de determinação directa de pressão osmótica numa cellula vegetal com manômetro (1938)

Proposed the hypothesis of active membrane (1948)

The “active membrane”: an hypothesis to explain the transfer of water and solutes in plants, as depending upon respiration. Rev. Canad. Biol. 8:157-72, 1949

Developed Arens technique or callose test

Prova de calose por meio da microscopia a luz fluorescente com applicações do método. Lilloa 18:71-75, 1949

Uma doença da ervilha (Pisum sativum L.) causada por fatores meteorologicos. Lilloa 21 (1949) 

Proposed oligotrophic scleromorphism in Cerrado plants 

O cerrado como vegetação oligotrófica. Bol. Fac. Cien. Letras Univ. S. Paulo Ser. Bot. 224(15): 59-77, 1958

Ein polaritaets und steurungsmechanismus der Zelle. Protoplasma (1960)