Aloe is really great for cuttings and seedlings - Salicylic Acid, IAA, etc.
The ten main areas of chemical constituents of Aloe vera include: Amino Acids, Anthraquinones, Enzymes, Minerals, Vitamins, Lignins, Monosaccharide, Polysaccharides, Salicylic Acid, Saponins, And Sterols.
Amino acids found in Aloe vera include: Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Valine,And Tryptophan. Some Of The Other Non-Essential Amino Acids Found In Aloe Vera Include Alanine, Arginine, Asparagine, Cysteine, Glutamic Acid, Glycine, Histidine, Proline, Serine, Tyrosine, Glutamine, And Aspartic Acid.
Enzymes include Amylase, Bradykinase, Catalase, Cellulas, Lipase, Oxidase, Alkaline Phosphatase, Proteolytias, Creatine Phosphokinase and Carboxypeptidase.
Aloe vera also contains Vitamins B1, B2, B3, B5, B6, and B12 along with Choline, Calcium, Magnesium, Zinc, Manganese, Chromium, Selenium. Additional elements found in Aloe vera include Copper, Iron, Potassium, Phosphorus, And Sodium.
I also have a belief that seeds are awaiting specific enzymes, pgh's, pgr's, humic acids, etc from the soil, or good vermicompost. If a seed needs water (rain) to wash off the anti rooting hormones encoded on the outer seed, it only makes sense it needs/expects/awaits other factors from nature.
Peace!
P-