Characteristics of the transport and distribution of photosynthetic products during fruit expansion of Camellia gauchowensis
[Objective]This study endeavors to elucidate the spatiotemporal dynamics of photosynthate transport and allocation in Camellia gauchowensis during fruit expansion in order to discern the relationship between fruit quality and photosynthate partitioning in oil tea cultivars possessing distinctive southern traits.Our ultimate aim is to furnish scientific and technological underpinnings for the advancement of high-quality oil tea production in South China.[Method]The C.gauchowensis were subjected to pulse-chase 13C labeling for 2 h,and the different organs were collected at 0,6,24,48,and 72 h to analyze the 13C levels and examine the transport and distribution of recently synthesized photosynthates in the trees.The sugar components features and the accumulation and distribution characteristics of non-structural carbohydrates(NSC)were simultaneously determined in leaves,seeds,and fruit peel.[Result]1)The rate of photosynthate transport to each sink organ reached the highest point from 0 to 6 h after labeling ended and stabilized from 6 to 48 h.2)After the photosynthates transport stabilized,the distribution of recently synthesized photosynthates in each organ was in order of leaves＞kernels＞peels＞branches.3)The photosynthates were primarily stored in the form of fructose in various organs,with a high sucrose concentration gradient between leaves,seeds,and fruit peel.4)Non-structural carbohydrate(NSC)accumulation in the peel was the highest,followed by the leaf and seed kernel.Furthermore,we observed that the soluble sugar to starch ratio was the most prominent in the seed kernel,followed by the peel,and least in the leaves.[Conclusion]The photosynthetic products generated in the leaves of C.gauchowensis during the period of fruit expansion exhibited rapid translocation to the reservoir organs within a time frame of 24 hours post-synthesis.The distribution ratio of recently synthesized photosynthates in all organs was highest in leaves,which favored nutritional growth but not reproductive growth in C.gauchowensis.The high sucrose concentration in leaves and fruit peel was one of the reasons for the thicker peel in C.gauchowensis.The analysis revealed that the elevated soluble sugar to starch ratio in the seed kernels and peel could be attributed to the concurrent processes of peel development,fatty acid synthesis,and oil accumulation during the phase of rapid fruit expansion.Specifically,these processes were responsible for the marked increase in the soluble sugar to starch ratio observed in the seed kernels and peel.
transport and distribution characteristics of photosynthates13C pulse labellingsugar componentsnon-structural carbohydratesCamellia gauchowensis
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