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Wheat plants are very sensitive to high temperature stress during grain filling. Effects of heat priming applied to the first generation on tolerance of the successive generation to post-anthesis high temperature stress were investigated. Compared with the progeny of non-heat primed plants (NH), the progeny of heat-primed plants (PH) possessed higher grain yield, leaf photosynthesis and activities of antioxidant enzymes and lower cell membrane damage under high temperature stress. In the transcriptome profile, 1430 probes showed obvious difference in expression between PH and NH. These genes were related to signal transduction, transcription, energy, defense, and protein destination and storage, respectively. The gene encoding the lysine-specific histone demethylase 1 (LSD1) which was involved in histone demethylation related to epigenetic modification was up-regulated in the PH compared with NH. The proteome analysis indicated that the proteins involved in photosynthesis, energy production and protein destination and storage were up-regulated in the PH compared with NH. In short, thermos-tolerance was induced through heritable epigenetic alternation and signaling transduction, both processes further triggered prompt modifications of defense related responses in anti-oxidation, transcription, energy production, and protein destination and storage in the progeny of the primed plants under high temperature stress. It was concluded that trans-generation thermo-tolerance was induced by heat priming in the first generation, and this might be an effective measure to cope with severe high-temperature stresses during key growth stages in wheat production.

Drought is the major abiotic stress that decreases plant water status, inhibits photosynthesis, induces oxidative stress, restricts growth and finally lead to the reduction of wheat yield. It has been proven that drought priming during vegetative growth stage could enhance tolerance to drought stress at grain filling in wheat. However, whether drought priming imposed at grain filling in parental plants could induce drought tolerance in the offspring is not known. In this study, drought priming was successively applied in the first, the second and the third generation of wheat to obtain the plants of T1 (primed for one generation), T2 (primed for two generations), T3 (primed for three generations). The differently primed plants were then subjected to drought stress during grain filling in the fourth generation. Under drought stress, the parentally primed (T1D, T2D, T3D) plants, disregarding the number of generations, showed higher grain yield, leaf photosynthetic rate and antioxidant capacity as well as lower O2•− release rate and contents of H2O2 and MDA than the non-primed (T0D) plants, suggesting that drought priming induced the transgenerational stress tolerance to drought stress. Moreover, the parentally primed plants showed higher leaf water status, which may result from the higher contents of proline and glycine betaine, and higher activities of Δ1-pyrroline-5-carboxylate synthetase (P5CS) and betaine aldehyde dehydrogenase (BADH), compared with the non-primed plants under drought stress. In addition, there was no significant difference among three generations under drought, and the drought priming in parental generations did not affect the grain yield of the offspring plants under control condition. Collectively, the enhanced accumulation of proline and glycine betaine in the parentally primed plants could have played critical roles in parental priming induced tolerance to drought stress. This research provided a potential approach to improve drought tolerance of offspring plants by priming parental plants.

Wheat plants were subjected to combined waterlogging and shading stress (WS) at 0–7, 8–15, 16–23 and 24–31 days after anthesis (DAA), respectively. Compared to the non‐stressed plants, WS significantly decreased the final grain yield. Grain number was dramatically lowered by WS imposed at 0–7 DAA but hardly affected by other WS treatments; while the thousand‐kernel‐weight was unaffected by WS imposed at 0–7 DAA and lowered by other WS treatments. Photosynthate accumulation in the stem was decreased by WS imposed at 0–7 and 8–15 DAA, but was unaffected by WS imposed at later stages. Grain‐filling rate was decreased, although the apparent remobilization of carbohydrate reserves from stem to grain was stimulated under WS. The carbohydrate reserves stored in the lower stem internodes were activated earlier and remobilized much more than those in the upper internodes; however, the proportion of the apparent remobilized reserves among the different stem internodes was consistent for all treatments. WS decreased contents of fructans, fructose and sucrose in the stem, which coincided with increased activity of fructan exohydrolase and decreased activities of sucrose‐1‐fructosyltransferase and fructan‐1‐fructosyltransferse. The results indicate that post‐anthesis WS stimulated carbohydrate reserves remobilization by modifying the activities of the fructans‐catalysing enzymes in the stem.