Abstract: A new vessel for large scale plant tissue culture with a compartmentalized reservoir and corresponding media but without regular closure to close the vessel, so that the plant tissues cultured with the vessel are under a normal ecological air environment. Instead of the regular closure, a layer of sterile powder material is dusted on the top of the media and on a special circumferential fold on the wall of the vessel, until all the media, the fold, and the plant tissues are buried. Thus a continuous powder buried from wall to wall is formed against microbes from getting into the vessel. Since the normal ecological air environment provides a natural light, variable and normal humidity, air current, and enough CO.sub.2, etc., the plantlets cultured from the new vessel harden themselves while they are gradually growing out of the powder layer, just like seedlings gradually growing out of soil in nature.

Abstract: An artificial seed has a powder structure or powder padded layer as a sealing material for anti-contamination purpose. This powder layer, 2-30 mm preferably 5-20 mm in thickness, consists of numerous fine sandy hydrophobic particles. The openings among the particles are small and winding enough to block micro-organisms from penetrating this dry and nutrientless layer into the seed, but not enough to block the needed oxygen. The hydrophobic nature of the particles is also effective to block water permeation and microbes therein, but not effective to block the tissue to grow out of the seed. The powder layer can cover any exposed part of the artificial seed. For the artificial seeds with a water-proof tough shell, the powder layer covers only the mouth or mouths of the shell. But for those with a water-soluble capsule, or water-soluble film, it covers all over the contents of the seeds. In both cases, the powder layer is again covered with the water-soluble film to kept the powder particles in position.