Rootstocks and Plant Water Relations Affect Sugar Accumulation of Citrus Fruit Via Osmotic Adjustment
By G. H. Barry, W. Castle, F. S. Davies. Journal of the American Society for Horticultural Science, 2004
86 citations recorded by the source corpus.
Citrus rootstocks have well-known effects on tree size, crop load, fruit size, and various fruit quality factors. Fruit from trees budded on invigorating rootstocks are generally larger with lower soluble solids concentration (SSC) and titratable acidity compared to fruit from trees budded on less invigorating rootstocks. Although it is unclear how rootstocks exert their influence on juice quality of Citrus L. species, plant water relations are thought to play a central role. In addition, the larger fruit size associated with invigorating rootstocks and the inverse relationship between SSC and fruit size implies that fruit borne on trees on invigorating rootstocks have lower SSC due to dilution effects in larger fruit. To determine how rootstock type affects sugar accumulation in fruit of Citrus species, controlled water-deficit stress was applied to mature `Valencia' sweet orange [C. sinensis (L.) Osb.] trees on Carrizo citrange [C. sinensis × Poncirus trifoliata (L.) Raf.] or rough lemon (C. jambhiri Lush.) rootstocks. Withholding water from the root zone of citrus trees during stage II of fruit development decreased midday stem water potential and increased the concentrations of primary osmotica, fructose and glucose. Sucrose concentration was not affected, suggesting that sucrose hydrolysis took place. Increased concentrations of sugars and SSC in fruit from moderately water-stressed trees occurred independently of fruit size and juice content. Thus, passive dehydration of juice sacs, and concentration of soluble solids, was not the primary cause of differences in sugar accumulation. Controlled water-deficit stress caused active osmotic adjustment in fruit of `Valencia' sweet orange. However, when water-deficit stress was applied later in fruit development (e.g., stage III) there was no increase in sugars or SSC. The evidence presented supports the hypothesis that differential sugar accumulation of citrus fruit from trees on rootstocks of contrasting vigor and, hence, plant water relations, is caused by differences in tree water status and the enhancement of sucrose hydrolysis into component hexose sugars resulting in osmotic adjustment. Therefore, inherent rootstock differences affecting plant water relations are proposed as a primary cause of differences in sugar accumulation and SSC among citrus rootstocks.
Subfields: Plant Science
View Paper: https://www.semanticscholar.org/paper/9212a8295ce825a11be19c25f5394885ad0b645e
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Citations in the corpus
- Some aspects of citrus ecophysiology in subtropical climates: re-visiting photosynthesis under natural conditions (2007, background): “A general model for water management in citrus orchards is not a simple matter since (i) there are various citrus scion and rootstock combinations (Medina et al., 1998, 2005; Machado et al., 2002; Barry et al., 2004; Cerqueira et al., 2004) and (ii) the environmental conditions differ significantly ”
- Deficit irrigation in fruit trees and vines in Spain. (2010, background): “A fact that has been also found in Valencia oranges on Carrizo citrange and rough lemon rootstocks (Barry et al., 2004).”