Fig 1.
Effect of ALA pre-treatment on leaf morphology and RWC in fig plants under waterlogging.
A to E: Leaf morphology on the 6th day under different treatments. ALA1: Waterlogging after 5 mg·L1 ALA pretreatment. ALA2: Waterlogging after 10 mg·L-1 ALA pretreatment. ALA3: Waterlogging after 20 mg·L-1 ALA pretreatment. F: Leaf relative water content (RWC) on the 6th day under different treatments. Data indicate mean ± standard deviation (SD) of six replicates (n = 6). The same letters at the top of each bar indicate no significant differences at P<0.05.
Fig 2.
ALA pretreatment reduces leaf production rate, MDA, and proline content under waterlogging.
A to C: Dynamic changes of leaf superoxide anion production rate (, A), malondialdehyde (MDA, B), and proline content (C) under different treatments. ALA1: Waterlogging after 5 mg·L1 ALA pretreatment. ALA2: Waterlogging after 10 mg·L-1 ALA pretreatment. ALA3: Waterlogging after 20 mg·L-1 ALA pretreatment. Data indicate mean ± standard deviation (SD) of six replicates (n = 6). The same letters at the top of each bar indicate no significant differences at P<0.05.
Fig 3.
ALA pretreatment increases chlorophyll content and chlorophyll b/a under waterlogging.
A to D: Dynamic changes of chlorophyll a (Chl a, A), chlorophyll b (Chl b, B), total chlorophyll (Chl a+b, C), and the ratio of chlorophyll b/a (Chl b/a, D) under different treatments. ALA: Waterlogging after 5 mg·L-1 ALA pretreatment. Data indicate mean ± standard deviation (SD) of six replicates (n = 6). Different letters on the same time point indicate significant differences at P<0.05.
Fig 4.
Effect of ALA pre-treatment on leaf chlorophyll fast fluorescence characteristics under waterlogging.
A: Leaf chlorophyll a fast fluorescence transient on the 6th day under different treatments. In the O-K-J-I-P nomenclature, O stands for the origin (minimum), K- I are intermediate inflections, and P is for peak. Different small letters indicate significant differences between I-P phase of different treatments at P<0.05. B to D: Leaf chlorophyll fluorescence parameters on the 6th day under different treatments. ALA: Waterlogging after 5 mg·L-1 ALA pretreatment. Vj: Relative variable fluorescence intensity at the J-step. Wk: Amplitude of the K step as a parameter of the PSII donor side. Mo: Approximated initial slope of the fluorescence transient. φPo: Maximum quantum yield for primary photochemistry. ψo: Probability that a trapped exciton moves an electron into the electron transport chain beyond QA-. φEo: Quantum yield for electron transport. φDo: Quantum yield for heat dissipation. Fi-p: Slow PQ pool reduced ability. Fj-I: Fast PQ pool reduced ability. PItotal: Performance index for energy conservation from excitation to the reduction of PSI end acceptors. PIABS: Performance index on absorption basis. PIcs: (Performance index on cross section basis. δRo: Probability with which an electron from the intersystem electron carriers moves to reduce end electron accepters at the PSI acceptor side. φRo: Quantum yield for reduction of end electron accepters at the PSI acceptor side. ABS/RC: Absorption flux per reaction center (RC). DIo/RC: Dissipated energy flux per RC. TRo/RC: Trapped energy flux per RC. ETo/RC: Electron transport flux per RC. ABS/CSo: Absorption flux per cross section (CS, at t = 0). DIo/CSo: Dissipated energy flux per CS (at t = 0). TRo/CSo: Trapped energy flux per CS (at t = 0). ETo/CSo: Electron transport flux per CS (at t = 0). When t = tFmax, CSo was replaced by CSm. In figure B-D, * near each parameter indicate significant differences at P<0.05 between treatments. Data indicate mean ± standard deviation (SD) of 6 replicates (n = 6).
Fig 5.
ALA pretreatment increases leaf SOD and POD activities under waterlogging.
A, B: Dynamic changes of superoxide dismutase (SOD, A) and perioxidase (POD, B) under different treatments. ALA: Waterlogging after 5 mg·L-1 ALA pretreatment. Data indicate mean ± standard deviation (SD) of six replicates (n = 6). Different letters on the same time point indicate significant differences at P<0.05.
Fig 6.
Effect of ALA pre-treatment on root vigor and root fermentative enzyme activities in fig plants under waterlogging.
A: Root vigor on the 4th and 6th day. B: Alcohol dehydrogenase (ADH) activities on the 4th and 6th day. C: Lactate dehydrogenase (LDH) activities on the 4th and 6th day. Data indicate mean ± standard deviation (SD) of six replicates (n = 6). Different letters on the same time point indicate significant differences at P<0.05.