Changes in endogenous hormone content and cellular structure during seed storage of Quercus mongolica

The Quercus mongolica seeds are recalcitrant and not resistant to storage. In order to provided scientific basis and technical reference for the reasonable storage of Q. mongolica seeds, the changes of endogenous hormones and cellular structure characteristics of seeds under different initial moisture content and storage temperatures were explored.

The silica gel drying was used to control the initial seed moisture content to 50% (initial moisture content after harvesting), 40%, 30% and 20%, and stored at low-temperature (4 ℃) and room-temperature (20 ℃) respectively. During the storage, the seed vigor, endogenous hormones, and cell microstructure of Q. mongolica seeds were detected.

1) The germination of newly harvested Q. mongolica seeds could reach 100%, and the seed vigor was not affected after rapid drying by silica gel. 2) During seed storage, the rates of seeds vigor loss were different at different initial moisture content and storage temperatures. The optimal moisture content for storing Q. mongolica seeds was 30%-40%, and low-temperature storage was superior to room-temperature storage. 3) Under room-temperature storage, with the increase of seed initial moisture content, the mold increased seriously, while reducing seed initial moisture content or under low-temperature storage, the seed deterioration was mainly browned or softened. 4) During the storage, the GA₃ content of Q. mongolica seeds was decreased with the decrease of the seed initial moisture content, and it decreased sharply within the first 14 days of storage. The ABA content responded differently to the storage temperature. ABA content was stable under low-temperature storage, while under room-temperature storage conditions, ABA content changed differently with different initial seed moisture contents. 5) Microstructure observation showed that the cotyledon cells of newly harvested Q. mongolica seeds were closely arranged and regular, and had no inclusions, while plumule cells were small and loosely arranged. After 14 days of storage, seed cells produce inclusions. The seed deterioration was accompanied by strong cell shrinkage or damage, unclear cell boundaries, and loss of internal substances.

Reducing the initial moisture content and storage temperature of Q. mongolica seeds is beneficial to improve seed storage tolerance, but seed water content less than 20% is not conducive to seed storage.