Abstract
Satsuma mandarin fruit (Citrus unshiu Mark.) photosynthesizes as comparable to leaf at about 100 days after full bloom (DAFB). In this study, translocation and accumulation of fruit-fixed photosynthate were investigated by using 14CO2. When fruit at 108 DAFB was exposed to 14CO2 for 48 h under 135 photosynthetic photon flux density (PPFD), 14C-sucrose, 14C-glucose and 14C-fructose were detected not only in flavedo but juice sac; more than 50 % of fruit assimilated 14C-sugars were present in juice sac. Thus, majority of rind-fixed photosynthate are infiltrated into juice sac and accumulated there within 48 h after assimilation. Although 14C-sucrose was predominant at flavedo where high SS (sucrose synthase) activity toward synthesis was present, the amount decreased gradually from the outside (flavedo) to the inside (juice sac) of fruit. In vascular bundle, strong SS toward cleavage and soluble acid invertase activities were involved, and 14C-fructose was predominant in juice sac. Accordingly, rind-fixed photosynthate is once converted to sucrose, the translocated sugar in Citrus, at flavedo by SS toward synthesis, and loaded on vascular bundle through symplastic and/or apoplastic movement in the albedo tissue. In the vascular bundle, sucrose may be degraded by SS toward cleavage and invertase, and resulting hexoses transported symplastically to the juice sac through juice stalk.
Similar content being viewed by others
References
Arakawa O, Uematsu N, Nakajima H (1994) Effect of bagging on fruit quality in apples. Bull Fac Agric Hirosaki Univ 57:25–32 (in Japanese with English summary)
Blanke MM (1995) Regulation of respiration in apple, avocado and citrus orange fruit. Acta Hortic 398:139–146
Blanke MM, Bower JP (1991) Small fruit problem in Citrus trees. Trees 5:239–243
Blanke MM, Lenz F (1989) Fruit photosynthesis. Plant Cell Environ 12:31–46
Bradford MM (1976) A rapid and sensitive method for the quantitation of microgram quantities of protein using the principle of protein-dye binding. Anal Biochem 72:248–254
Coleman HD, Ellis DD, Gilbert M, Mansfield SD (2006) Up-regulation of sucrose synthase and UDP-glucose pyrophosphorylase impacts plant growth and metabolism. Plant Biotech J 4:87–101
Hiratsuka S, Yokoyama Y, Nishimura H, Miyazaki T, Nada K (2012) Fruit photosynthesis and phosphoenolpyruvate carboxylase activity as affected by lightproof fruit bagging in Satsuma mandarin. J Amer Soc Hortic Sci 137:215–220
Hiratsuka S, Suzuki M, Nishimura H, Nada K (2015) Fruit photosynthesis in Satsuma mandarin. Plant Sci 241:65–69
Huang C, Yu B, Teng Y, Su J, Shu Q, Cheng Z, Zeng L (2009) Effects of fruit bagging on coloring and related physiology, and qualities of red Chinese sand pears during fruit maturation. Sci Hortic 121:149–158
Huber SC, Huber JL (1996) Role and regulation of sucrose-phosphate synthase in higher plants. Ann Rev Plant Physiol Plant Mol Biol 47:431–444
Koch KE (1984) The path of photosynthate translocation into citrus fruit. Plant Cell Environ 7:647–653
Koch KE, Avigne WT (1990) Post-phloem, nonvascular transfer in Citrus. Kinetics, metabolism, and sugar gradients. Plant Physiol 93:1405–1416
Kubo T, Maegawa M, Hiratsuka S (1996) Relationship between rind surface morphology and sugar concentration in the juice of Satsuma mandarin fruit. J Japan Soc Hortic Sci 65:447–453 (in Japanese with English summary)
Kubo T, Hohjo I, Hiratsuka S (2001) Sucrose accumulation and its related enzyme activities in the juice sacs of Satsuma mandarin fruit from trees with different crop loads. Sci Hortic 91:215–225
Lopez Y, Riano N, Mosquera P, Cadavid A, Arcila J (2000) Activities of phosphoenolpyruvate carboxylase and ribulose-1, 5-bisphosphate carboxylase/oxygenase in leaves and fruit pericarp tissue of different coffee (Coffea sp.) genotypes. Photosynthetica 38:215–220
Lowell CA, Tomlinson PT, Koch KE (1989) Sucrose-metabolizing enzymes in transport tissues and adjacent sink structures in developing Citrus fruit. Plant Physiol 90:1394–1402
Ryuhan T, Hiratsuka S, Nada K (2013) Effect of lightproof fruit bagging on fruit growth and quality in Japanese pear. Hortic Res 12 (suppl. 2):88 (in Japanese)
Suzuki A, Kanayama Y, Yamaki S (1996) Occurrence of two sucrose synthase isozymes during maturation of Japanese pear fruit. J Amer Soc Hortic Sci 121:943–947
Watanabe M, Oyamada T, Suzuki A, Murakami M, Sugaya S, Komori S, Arakawa O (2011) Comparison of sugar accumulation characteristics in ‘Haruka’ and ‘Fuji’ apple fruits. Hortic Res 10:565–571 (in Japanese with English summary)
Zhao C, Hua LN, Liu XF, Li YZ, Shen YY (2016) Sucrose synthase FaSS1 plays an important role in the regulation of strawberry fruit ripening. Plant Growth Regul. doi:10.1007/s10725-016-0189-4
Acknowledgments
The authors thank to Mr. T. Kurosawa of Mie University for his help in radioisotope operation. This work was supported in part by the Grant-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology of Japan (Nos. 19658013 and 23658029).
Author information
Authors and Affiliations
Corresponding author
Electronic supplementary material
Below is the link to the electronic supplementary material.
10725_2016_204_MOESM2_ESM.pptx
Supplementary Fig. 2. Comparison of 14C-sugar accumulation among juice sacs from developmentally different fruits. Juice sacs were sampled after exposing fruits to 14CO2 under 135 PPFD for 48 h. A: Radioactivity on fresh weight base. B: Radioactivity on fruit base. Vertical bars indicate SE. (PPTX 56 KB)
Rights and permissions
About this article
Cite this article
Hiratsuka, S., Nakayama, S., Tamura, S. et al. Translocation and accumulation of fruit-fixed photosynthate in Satsuma mandarin. Plant Growth Regul 81, 277–282 (2017). https://doi.org/10.1007/s10725-016-0204-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10725-016-0204-9