I want to collect seeds from various farms within the agro-pastoral region of the Western Cape Province of South Africa to determine the quality of the soil seed bank on each of the farms and how different pasture/crop rotation strategies influences not only the quantity of seeds in the soil, but also their vertical distribution within soils. I was also considering trying to determine the natural breakdown of seed coat dormancy on each of the farms by collecting soil samples at various stages after seed formation in order to try and get a rough timeline as to how long this process will take. However, I am not sure how I should go about testing the 'hardness' of the seeds. Would normal petri dish germination trials with the collected seeds be enough to test the ability of seeds to germinate at various time intervals after seed formation?
You seem to be assuming that there is no physiological dormancy in these species. You should check this.
If you want to look at the loss of dormancy in the soil you need to collect seeds from plants and add them to the soil at a known time. You cannot use seeds already in the soil as you do not know in which year they entered the soil seed bank.
Good luck.
Besides the aspects mentioned, most important would be to check the viability of these seeds (tetrazolium test).
Regarding hardness, you can test the rate of imbibition (beyond germination) the seeds collected in the soil and compare them with freshly collected from a representative seed sample of plants of these species. It will be hard work, but it may explain some of their questions.
this species have physical (seed coat), check seed germination % and TTC, TZ test
Dear
First step is to make the diagnosis if the seeds to be tested were feasible. This viability is subject to physiological maturity, ie, if the seeds completed the cycle and become mature. If mature may or may not germinate, since the germination depends on several factors, the most important of water. Another factor may be physical impediment water permeability, which for many legume seeds must use the process of scarification. These tests are easy to be performed. Another factor that leads to lower impediment to germination of legumes to the soil naturally deposited is the residence time in the soil and under varying conditions of temperature and humidity. These climate changes help to scarify the seeds and their germination will occur gradually. For the specific case of alfalfa (Medicago sativa) and clover (Trifolium repens), because they are hard seeds, to solve simple mechanical scarification (lenient friction on rough surface). Important: scarification should be used if found impediment to water permeability.
hug
Depending on your question there are a range of ways you can do this. I have done in situ breakdown studies in the field where we placed a known number of seed in a mesh bag and then sampled at particular intervals. There are several examples of this methodology in the literature - I suggest you look up the following references for some guidelines
Smith FP, Cocks PS, Ewing MA (1996) Aust. J. Agr. Res. 47, 775-785.
Taylor GB (1996) Aust. J. Agr. Res. 47, 575-586.
Taylor GB, Ewing MA (1992) Aust. J. Exp. Agr. 32, 331-337
Bell LW, Lloyd DL, Bell KL, Johnson B, Teasdale KC (2003) Aust. J. Exp. Agr, 43, 1303-1310.
A nice review of the factors that influence the breakdown of seed dormancy (hardseeds) in Trifolium and Medicago was published by Graham Taylor in 2005.
Taylor GB (2005) Hardseededness in Mediterranean annual pasture legumes in Australia: a review. Australian Journal of Agricultural Research 56, 645-661.
The dehydration of seeds is fundamental for the development of seed dormancy in these annual legumes and you need to consider seed moisture content when setting up in-situ studies.
Hello dear sir
I think to breakdown the seed dormancy for medicago and Trifolium you can test your seeds by different temperature along with different times by germinator & petri dish
Best regards, A.Ggaseemi-Arian
Agree with Clinton Revell above, you also may like to read some papers by Lesins and Lesins re the medics and hardseed
regards
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