Title: Seed Dormancy in Rosa as a Function of Climate
Authors: G. J. VonAbrams; M. E. Hand
Published in: American Journal of Botany, Volumn 43, Pages 7-12, (1956).
Abstract: “Germination studies have been made of ten hybrid rose seed populations over a five-year period, and the results compared to variations in climate occurring during the 30-day and 60-day periods preceding harvest. Controlled hand pollinations and subsequent growth of fruit and seed were carried out in the field. Year-to-year environmental or circumstantial variations amenable to control in the field were reduced to a minimum, leaving climate as the major variable. The dormancy of hybrid rose seeds, and the consequent germination pattern in time, may vary widely between years, and low-temperature treatment is not invariably prerequisite to extensive germination. Good correlation is’ indicated ,between germination and preharvest climate, particularly with the mean of, the average daily temperatures for the 30-day period preceding harvest. Aseptic culture of excised embryonic plants provided high uniform germination for all five years of the study, indicating that the embryo itself is generally complete and that its potential germinability was not influenced by the climatic variation encountered. The validity of the relationship between pre-harvest climate and seed dormancy’ is further substantiated by the results of, experiments in which seed-bearing plants were transferred to a green-house cubicle in which they were provided high temperature and light. The subsequent germination of seeds’ from these plants indicates a marked reduction in dormancy as compared to field-grown controls.”
Hi Henry. I noticed in the thread that you recommended sand. I was taught (not for roses) to use small-grained vermiculite except for moisture sensitive plants because of the vermiculites absorbtive properties in “sucking up” parts of the seed coat’s chemicals. Just curious as to how you fell about that. It seems to work but if sand is better then well–sand is better lol.
-Mike
Hi Henry. I noticed in the thread that you recommended sand. I was taught (not for roses) to use small-grained vermiculite except for moisture sensitive plants because of the vermiculites absorbtive properties in “sucking up” parts of the seed coat’s chemicals. Just curious as to how you fell about that. It seems to work but if sand is better then well–sand is better lol.
-Mike
Vermiculite may cause lung problems due to contamination with asbestos.
Http://yosemite.epa.gov/R10/OWCM.NSF/d14dabb756dc1fb3882565000062f164/a269a8b80a6dd40e882568af005b994b?OpenDocument
EPA Quote from link given (Last Updated (mm/dd/yy): 02/28/2003)
"I know there is vermiculite in my potting soil. Is it dangerous?
Vermiculite alone should not cause harmful health effects. However, as with any particulate matter, breathing in large amounts of particles can cause irritation to the nose and throat. Some vermiculite contains asbestos as an impurity. For the asbestos to cause harmful health effects, it must exist as tiny free fibers that could be inhaled or ingested.
A person must generally be exposed to asbestos for a long period of time (10 or more years) before health effects occur.
Vermiculite is used in potting soil for plant generation, where it appears as bright gold or silver colored flakes. The Libby vermiculite should not be confused with the white plastic substance also found in many potting soil mixtures."
Link: yosemite.epa.gov/R10/OWCM.NSF/d14dabb756dc1fb3882565000062f164/a269a8b80a6dd40e882568af005b994b?OpenDocument
Hmmm… maybe I should take my parent plants out of the greenhouse a month before the start of harvest.
Thanks, Henry. You are right. Safety should be in high consideration.