Comparison of Photosynthetic Characteristics between Diploid Potato and Its Chromosomedoubled Individuals

PurposeThe photosynthetic capacity of plants largely reflects its ability to accumulate dry matter, while the photosynthetic capacity of polyploid plants is generally stronger than that of diploids or haplotypes. This study aimed to analyze the photosynthetic physiological characteristics of diploid potato and artificially induced chromosome doubling individuals.

MethodsDiploid potato line and doubled individuals obtained by colchicine were used as experimental materials. Using a Li-6400 portable photosynthesis system, we measured the photosynthetic parameters at different stages after transplanting, and the light response curves and CO₂ response curves at flowering stage.

ResultsThe net photosynthetic rate (P_n) of the doubled individuals and the diploid showed a trend of increase first and then decrease, and reached a peak at 60 days after transplanting. During the same period, the P_n of the doubled individuals was higher than that of the diploid, and showed a significant difference at 60 days and 75 days after transplanting; the maximum net photosynthetic rate (P_nmax) and light saturation point (LSP) of doubled individuals were higher than those of diploid, which increased by 16.12% and 13.00%, respectively; the light compensation point (LCP) and CO₂ compensation point (CCP) were lower than diploid, but diploid and its doubled individuals had no difference in apparent quantum efficiency and carboxylation efficiency.

ConclusionThe ability of doubled individuals to use weak light is stronger than that of diploid. Doubled individuals have higher photosynthetic capacities than diploid individualsunder both high and low light conditions. They also can use low concentrations of CO₂, and have the ability to fix and convert CO₂. In sum, the photosynthetic capacity of the doubled individuals is higher than that of the diploid.