Chlorophyll evaluation on leaves of 'Sauvignon Blanc' during vegetative growth in São Joaquim, Santa Catarina, Brazil

Chlorophylls are the most abundant natural pigments in plants. During leaf ontogeny, variations are observed on pigment concentrations, presenting gradual chlorophyll degradation during senescence period. The aim of this study was to determine chlorophyll levels and Spad index in grapevine leaves of 'Sauvignon Blanc' grown in São Joaquim, Santa Catarina, Brazil. Samples were taken fortnightly during 2011/2012, 2012/2013 and 2013/2014 seasons. Complete and healthy leaves were selected randomly, considering the fifth leaf in the shoot, in a commercial vineyard located at 1,293 m a.s.l. Leaves were colected from the initial phase of shoots development to foliar senescence. Spad index was determined using a portable chlorophyll meter. Chlorophyll a, chlorophyll b and total chlorophyll contents were determined. At the beginning of the cycle, leaves showed chlorophyll accumulation related to leaf expansion. From the flowering, an stabilization of foliar chlorophyll concentrations was observed. At the end of the berry ripening period, a significant reduction started. By the end of the cycle, the chlorophyll content on leaves decreased due to leaf senescence. Chlorophyll content and Spad index showed positive correlation. Total chlorophyll maximum was 2.5 mg g^-1 of fresh leaves, during grape development. Chlorophyll a content was more abundant in all evaluations. Foliar pigment content is variable throughout the growing season. Leaves on initial period of growing season showed accumulation of chlorophyll associated with leaf expansion. Foliar senescence of grapevine 'Sauvignon Blanc' presented a similar pattern in all seasons.