RELATIONSHIP BETWEEN ABSOLUTE AND RELATIVE CONTENT OF CHLOROPHYLL IN LEAVES OF OSIER

Os m\ue9todos tradicionais para a quantifica\ue7\ue3o de clorofilas implicam na destrui\ue7\ue3o das folhas, al\ue9m de serem demorados e dispendiosos. Uma alternativa aos m\ue9todos destrutivos \ue9 o uso de medidores port\ue1teis, dentre eles o SPAD 502, que mede a intensidade da cor verde das folhas, resultando no \uedndice SPAD (Soil Plant Analysis Development). No entanto, o \uedndice SPAD deve ser ajustado para o teor de clorofilas, conforme a esp\ue9cie de interesse. O objetivo do presente trabalho foi calibrar o \uedndice SPAD para a quantifica\ue7\ue3o de clorofilas em folhas de plantas de vime ( Salix viminalis ). Folhas desta esp\ue9cie, com tonalidade variando de verde-amarelada (clor\uf3tica) a verde-escura, foram avaliadas individualmente com o SPAD-502, seguido de quantifica\ue7\uf5es destrutivas dos teores de clorofilas a, b e totais, expressos em unidade de \ue1rea e massa fresca foliar. Houve elevado coeficiente de determina\ue7\ue3o (R\ub2) entre os valores de \uedndice SPAD e os teores de clorofila a, b e totais nas folhas, expressos em \u3bcg cm-2 de \ue1rea foliar (R\ub2 de 0,86; 0,88 e 0,93, respectivamente) e entre os valores de \uedndice SPAD e os teores de clorofilas b e totais, expressos em \u3bcg g-1 de massa fresca (R\ub2 0,79 e 0,81, respectivamente). Os resultados mostram que existe viabilidade no uso do clorofil\uf4metro SPAD 502, como alternativa aos m\ue9todos destrutivos, para a quantifica\ue7\ue3o de clorofilas (em unidade de \ue1rea; \u3bcg cm-2) em folhas de vimeiro.The traditional methods for chlorophylls quantification in leaves are destructive, time consuming and expensive. One alternative to the destructive methods involve the use portable devices, such as the chlorophyll meter SPAD-502, which measure the green color intensity of the leaves, by providing the SPAD (Soil Plant Analysis Development) index. However, the SPAD index must be adjusted to the chlorophylls content in the leaves of concerned specie. The objective of this work was to calibrate the SPAD index to quantify the chlorophylls content in leaves of osier ( Salix viminalis ). Leaves with colors ranging from yellow-green (chlorotic) to dark green were individually assessed with the SPAD-502 and, thereafter, destructively assessed for contents of chlorophylls a, b and total, expressed in terms of area and fresh mass of the leaves. There was a high determination coefficient (R2) between the SPAD index and the contents of chlorophylls a, b and total in the leaf, expressed in \u3bcg cm-2 of leaf area (R\ub2 of 0.86, 0.88 and 0.93,respectively) and of between the SPAD index and the contents of chlorophylls a and total, expressed in \u3bcg g-1 fresh weight (R\ub2 of 0.81 and 0.79, respectively). The results show the chlorophyll meter SPAD-502 is a suitable alternative to the destructive method to quantify chlorophylls (in area basis; \u3bcg cm-2) in leaves of osier