Figure 1.
Respiration rate, ethylene production and pulp firmness of papaya fruit during low temperature storage and ripening at 25°C after exogenous ethylene treatment.
A, respiration rate; B, ethylene production; and C, pulp firmness. 12°C, stored at 12°C; 7°C, stored at 7°C; 0 d 25°C EA, without low temperature-storage and directly treated with exogenous ethylene for ripening at 25°C; low temperature storage, at 12°C or 7°C storage; 25 d EA, treated with exogenous ethylene after 25 days at low temperature-storage; 30 d EA, treated with exogenous ethylene after 30 days at low temperature-storage. The values presented were obtained from three independent biological replicates. Mean values in graph followed by a different lower-case letters are significantly different at P≦0.05 by Duncan's multiple range tests. Different letters were used to indicate the dates of all treatments on the same time, and different time points calculated separately. The LSD was done with all treatments.
Figure 2.
Coloring index and photographs of papaya fruit during low temperature storage and ripening at 25°C after exogenous ethylene treatment.
A, coloring index; B, photographs. 12°C, stored at 12°C; 7°C, stored at 7°C; 0 d 25°C EA,without low temperature storage and directly treated with exogenous ethylene for ripening at 25°C; low temperature storage, at 12°C or 7°C storage; 25 d EA, treated with exogenous ethylene after 25 days at low temperature-storage; 30 d EA, treated with exogenous ethylene after 30 days at low temperature-storage. The values presented were obtained from 3 independent biological replicates.
Figure 3.
Expression levels of CpACSs in papaya fruit during low temperature-storage and ripening at 25°C after treatment with exogenous ethylene.
Sampling details were the same as those labeled in Fig 1. The y axis represents the relative fold difference of mRNA level, which was calculated to the method of 2−ΔΔCt using CpEIF as references gene. The values presented were obtained from 3 independent biological replicates. Samples from Day 0 (assigned an arbitrary quantity of “1”) were used as a calibrator to calculate the relative quantity of the results. Mean values in graph followed by a different lower-case letter are significantly different at P≦0.05 by Duncan's multiple range tests. Different letters were used to indicate the dates of all treatments on the same time, and different time points calculated separately. The LSD was done with all treatments.
Figure 4.
Expression levels of CpACOs in papaya fruit during low temperature-storage and ripening at 25°C after treatment with exogenous ethylene.
Sampling details were the same as those labeled in Fig 1. The details for quantitative real-time PCR details are as described in Fig 2.
Figure 5.
Expression levels of CpERS, CpETR1, CpEIN2 and CpEIL1 in papaya fruit during low temperature-storage and ripening at 25°C after treatment with exogenous ethylene.
Sampling details were the same as those labeled Fig 1. The details for quantitative real-time PCR details are as described in Fig 2.
Figure 6.
Expression levels of CpCTRs genes in papaya fruit during low temperature-storage and ripening at 25°C after ethylene treatment.
Sampling details were the same as those labeled Fig 1. The details for quantitative real-time PCR details are the same as those described in Fig. 2.
Figure 7.
Expression levels of CpEIN3s(CpEIN3a and CpEIN3b)and the EIN3 binding F-box (CpEBF1 and CpEBF2) genes in papaya fruit during low temperature-storage and ripening at 25°C after treatment with exogenous ethylene.
Sampling details were the same as those labeled Fig 1. The details for quantitative real-time PCR were the same as those described in Fig 2.
Figure 8.
Expression levels of CpERFs (ERF1∼4) in papaya fruit during low temperature-storage and ripening at 25°C after treatment with exogenous ethylene.
Sampling details were the same as those labeled Fig 1. Quantitative real-time PCR details are the same as those described in Fig 2.
Table 1.
Correlation between papaya fruit pulp firmness and expression levels of ethylene-related genes.
Table 2.
Correlation between coloring index of papaya fruit coloring index and expression levels of ethylene-related genes.