Post by bigbella on Sept 22, 2011 18:44:20 GMT
I had heard for some time about the supposed inhibitory effects of PPM (Plant Preservative Mixture) upon seeds and their germination rate; and I have found this not to be the case -- at least in the concentrations that I have used.
I had the opportunity of germinating a large number of Heliamphora seeds this Summer www.terraforums.com/forums/showthread.php?t=127412&highlight=heliamphora and divided the groups into those planted into a traditional 1:1 compost of milled sphagnum to quartz sand; a second group involved 2:3 Knudsen-C with 2 ml/L PPM; another, 2:3 Knudsen-C with 1 ml/L PPM; and a final group, 2:3 Knudsen-C with .75 ml/L PPM. Sterilization of the seed involved the use of either a 1:1 mix of PPM to distilled water or 1:1 PPM to 1:3 MS salts (without pH adjustment) for fifteen to twenty minutes (with equal success); though I now typically use a 4-8% solution of the same for three to four hours (it's far less expensive and just as effective).
Each group germinated after about four weeks like clockwork; and those in TC perfectly mirrored the behavior of those that were germinated in compost. One of the three species, Heliamphora exappendiculata had the lowest germination rate of the entire group; but that was consistent in all four sets (including compost); while another, H. sp. "Angasima" was, by far, the most vigorous across the board; and whose behavior -- so far as I could tell -- was entirely unaffected by the PPM under all three concentrations.
Heliamphora sp. "Angasima" 12 September 2011
10 October
The only conclusion that I could reach was that the freshness of the seed was of primary importance -- and that the various sterilization techniques growers used were of far greater issue than the use of any concentration of PPM (there are, after all, no shortages of bleached seeds out there); and that there exists so many variables among growers and TC adherents alike that that conclusion -- possible germination inhibition -- could not readily be reached, without knowing the age of the seed; the various sterilization techniques; the length of autoclaving of PPM-laden media; or any other number of factors . . .
I had the opportunity of germinating a large number of Heliamphora seeds this Summer www.terraforums.com/forums/showthread.php?t=127412&highlight=heliamphora and divided the groups into those planted into a traditional 1:1 compost of milled sphagnum to quartz sand; a second group involved 2:3 Knudsen-C with 2 ml/L PPM; another, 2:3 Knudsen-C with 1 ml/L PPM; and a final group, 2:3 Knudsen-C with .75 ml/L PPM. Sterilization of the seed involved the use of either a 1:1 mix of PPM to distilled water or 1:1 PPM to 1:3 MS salts (without pH adjustment) for fifteen to twenty minutes (with equal success); though I now typically use a 4-8% solution of the same for three to four hours (it's far less expensive and just as effective).
Each group germinated after about four weeks like clockwork; and those in TC perfectly mirrored the behavior of those that were germinated in compost. One of the three species, Heliamphora exappendiculata had the lowest germination rate of the entire group; but that was consistent in all four sets (including compost); while another, H. sp. "Angasima" was, by far, the most vigorous across the board; and whose behavior -- so far as I could tell -- was entirely unaffected by the PPM under all three concentrations.
Heliamphora sp. "Angasima" 12 September 2011
10 October
The only conclusion that I could reach was that the freshness of the seed was of primary importance -- and that the various sterilization techniques growers used were of far greater issue than the use of any concentration of PPM (there are, after all, no shortages of bleached seeds out there); and that there exists so many variables among growers and TC adherents alike that that conclusion -- possible germination inhibition -- could not readily be reached, without knowing the age of the seed; the various sterilization techniques; the length of autoclaving of PPM-laden media; or any other number of factors . . .
