Effect of 2,4-D on fruit sugar accumulation and invertase activity in sweet orange cv. Salustiana
2015; Southern Cross Publishing; Volume: 9; Issue: 2 Linguagem: Inglês
ISSN
1835-2693
AutoresAlexander Rebolledo Roa, Amparo García-Luis, José Luis Guardiola Bárcena, C. Huguet,
Tópico(s)Botanical Research and Applications
ResumoSmall fruit size is a common problem in Salustiana oranges. Many reports exist on the use of synthetic auxins to enhance citrus fruit size. Few of these studies delve on the effect of auxins on carbohydrate metabolism and its relationship with enzyme activity. Sugar balance is an important trait for fruit quality and depends on the enzymatic metabolism at different tissue levels. The effect of 2,4Dichlorophenoxyacetic acid (2,4-D) applications on fruit growth, sugar content, and invertase activity was studied on sweet orange fruit on 20-year-old trees of Citrus sinensis (L.) Osbeck cv. Salustiana. Carbohydrates were quantified via High-Performance Liquid Chromatography (HPLC) and the sugars released by the invertase activity with the Somogy–Nelson method. Then, the growth variables of the fruit were characterized (diameter and fresh and dry weight). The results showed that application of 2,4-D (20 mgL -1 , 3.6 L per tree) increased fruit size at maturity (5 mm). Application of 2,4-D increased sugar levels in the fruit and influenced the activity of the different invertase isoforms. The increased activity of the acid invertase isoform suggests a direct effect of 2,4-D on the increased fruit sink strength; it is also related to increased consumption of sugars during the initial fruit development stage.
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