Table 1.
Levels of leaf degeneration in cucumber seedlings.
Fig 1.
Effect of storage duration on morphological changes in cucumber seedlings.
Seedlings were stored at 12°C for 0, 2, 4, or 6 d in the dark (T0) or under a 15, 30, and 45 μmol·m-2·s-1 photosynthetic photon flux density (PPFD; T15, T30, and T45, respectively). Seedlings labeled as normal were grown under 250 μmol·m-2·s-1 PPFD (T250). Data represent the mean ± standard error (SE) of nine replicates. Different lowercase letters indicate significant differences among treatments on a given day according to the Tukey test (P < 0.05). ST, storage time; T, treatment.
Fig 2.
Changes in the chlorophyll concentration and leaf health index of cucumber seedlings during storage under different light conditions at 12°C.
Control seedlings were grown under normal conditions (T250). Data represent the mean ± SE (n = 9). Different lowercase letters indicate significant differences among treatments on a given day according to the Tukey test (NS, non-significant; ***, P < 0.001; **, P < 0.01). ST, storage time; T, treatment.
Fig 3.
Changes in chloroplast ultrastructure in the leaves of cucumber seedlings stored under different light conditions at 12°C.
(A–M) Seedlings were stored for 0 d (A), 2 d (B–E), 4 d (F–I), and 6 d (J–M) in the dark (B, F, J) or under 15 μmol·m-2·s-1 PPFD (C, G, K), 30 μmol·m-2·s-1 PPFD (D, H, L), or 45 μmol·m-2·s-1 PPFD (E, I, M) at 12°C. Scale bar: 1 μm. SG, starch grain; G, grana thylakoid.
Fig 4.
Changes in the soluble sugar content of the leaves of cucumber seedlings during storage under different light conditions at 12°C.
Control seedlings were grown under normal conditions (T250). Data represent the mean ± SE (n = 9). Different lowercase letters indicate significant differences among treatments on a given day according to the Tukey test (NS, non-significant; ***, P < 0.001; **, P < 0.01). ST, storage time; T, treatment.
Fig 5.
Changes in the net photosynthesis rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr) of cucumber leaves during storage under different light conditions at 12°C.
(A–D) Changes in Pn (A), Gs (B), Ci (C), and Tr (D) are shown. Control seedlings were grown under normal conditions (T250). Data represent the mean ± SE (n = 9). Different lowercase letters indicate significant differences among treatments on a given day according to the Tukey test (NS, non-significant; ***, P < 0.001; **, P < 0.01). ST, storage time; T, treatment.
Fig 6.
Recovery of the relative growth rate (RGR) of new leaves of cucumber seedlings after storage under different light conditions at 12°C.
Data represent the mean ± SE (n = 9). Different lowercase letters indicate significant differences among treatments on a given day according to the Tukey test (*, P < 0.05; **, P < 0.01; ***, P < 0.001). ST, storage time; T, treatment.
Fig 7.
Effect of storage duration on morphological changes in cucumber seedlings after transplanting.
Seedlings were stored at 12°C under different light intensities (T0, T15, T30, and T45) for 0, 2, 4, and 6 d. Seedlings labeled as normal were grown under 250 μmol·m-2·s-1 PPFD (T250). Data represent the mean ± SE (n = 9). Different lowercase letters indicate significant differences among treatments on a given day according to the Tukey test (P < 0.05). ST, storage time; T, treatment.
Fig 8.
Recovery of photosynthetic parameters of the leaves of cucumber seedlings stored at 12°C under different light intensities.
(A) Pn; (B) Gs; (C) Ci; Tr (D). Control seedlings were grown under normal conditions (T250). Data represent the mean ± SE (n = 3). Different lowercase letters indicate significant differences among treatments on a given day according to the Tukey test (NS, non-significant; ***, P < 0.001; **, P < 0.01). ST, storage time; T, treatment.