Foliar carbohydrates content and invertase activity in vines at São Francisco River Valley - Brazil

Abstract

-The irrigated agriculture at the São Francisco River Valley, Northeast Brazil, shows an increasing production of grapes for winery. Among the wines produced there the one obtained from Vitis vinifera L., cultivar Syrah, stands out due to its adaptation to the climatic conditions of the region. However, little is known about carbohydrates metabolism of vines cultivated in this region. The objective of this work was to evaluate sugar and starch contents and the invertase activity in vines leaves during two consecutive growing seasons. The experiment was carried out at Embrapa Semi-Árido and at Santa Maria Winery, respectively located in Petrolina and Lagoa Grande, Pernambuco-Brazil. Leaves were collected weekly from January to December of 2003 and assessed for reducing sugars, total soluble sugars and starch contents, as well as for acid (AI) and neutral invertases (NI). The results showed that reducing sugars, total soluble sugars and starch contents increased during fruit maturation and are influenced by temperature, radiation and insolation variations. The second growing season showed higher reducing sugars and total soluble sugars content and lower starch content in the leaves than the first one. AI activity was higher than NI activity and these also varied according to weather conditions. During berries ripening, leaves showed higher sugar content and invertase activity, suggesting a higher sugar metabolism and transport during this phase.

Metabolismo da videira ‘syrah’ no semiárido nordestino sob três estratégias hídricas

“…Esse aumento gradual nos açúcares era esperado como já definido por muitos autores (DANTAS et al, 2005;PEREIRA, 2007;DANTAS et al, 2007) em relação ao crescimento e desenvolvimento dos frutos da videira em função do acúmulo de fotoassimilados provenientes das folhas.…”

“…Desta forma, era de se esperar menor acúmulo nas folhas durante esse período. Esses resultados estão de acordo com os obtidos por Dantas et al (2005); Dantas, Ribeiro e Pereira (2007), onde o acúmulo de açúcares nas folhas aumenta durante o início da maturação, porém, é fortemente influenciado pelas variações climáticas.…”

“…Os resultados obtidos no presente estudo concordam com os obtidos por Dantas et al (2005). Além disso, a maior atividade média da IAP na estratégia ID ao final do ciclo em relação à IDC e IP caracteriza maior transporte de sacarose fotossintética pela via apoplástica das células.…”

Relationship Between Acid Invertase Activity and Sugar Content in Grape Species

“…A reversible cleavage of sucrose is catalyzed by sucrose synthesis (EC 2.4.1.13); in contrast, invertases (EC 3.2.1.26) catalyze the irreversible cleavage of sucrose to glucose and fructose. Among the carbohydrate metabolizing enzymes, the invertases are a group of β‐fructosidases eventually classified according to the isoelectric point, pH optimum for activity (acidic, neutral or alkaline), solubility (soluble or insoluble) and cellular localization (Quick 1996; Dantas et al . 2005).…”

Sucrose Metabolism and Transport in Grapevines, with Emphasis on Berries and Leaves, and Insights Gained from a Cross-Species Comparison

“…Grape leaves contain large amounts of AI activity throughout development, and the amount g −1 FW can be comparable to the pericarp (Table 2: [54,103,204]). VAI and CWAI transcripts are present, and AI activity is present in the soluble and insoluble fractions of extracts [54,75,103].…”