Oxygen-controlled priming of seed
The present invention relates the methods, compositions and devices for priming of plant seed, preferably seed of crop plants, and seeds obtained with the methods, compositions and devices, wherein the metabolic activity necessary for germination of the seed is not controlled by water but rather by the partial oxygen pressure and/or partial carbon dioxide pressure. In the methods of the invention, the partial oxygen or carbon dioxide pressure may be measured by oxygen/carbon dioxide sensitive fluorescent dye. The invention further relates to processes for producing a primed seed lot of a plant species and to a container comprising primed seed under an atmosphere with a partial oxygen pressure that is below the critical oxygen pressure.
1. A method of priming a seed of a given seed lot comprising:
(a) measuring for the given seed lot at least:
(i) the total amount of oxygen used per seed up to the moment of respiration acceleration; and,
(ii) the critical oxygen pressure;
(b) contacting the seed with a sufficient quantity of water and a sufficient quantity of oxygen to allow metabolic activity necessary for germination of the seed to take place; and,
(c) measuring the partial oxygen pressure for the seed lot;
(d) reducing the partial oxygen pressure to a level below the critical oxygen pressure determined in (a) at a time when the total amount of oxygen used per seed up to the moment of respiration acceleration determined in (a) is reached thereby preventing extension of at least one of root and shoot beyond a point at which the seed cannot be handled without serious risk of damage to the seed.
2. The method according to claim 1 , wherein the partial oxygen pressure is reduced by respiration of the metabolically active seed.
3. The method according to claim 2 , wherein the partial oxygen pressure is reduced in a hermetically sealed space.
4. The method according to claim 1 , wherein the partial oxygen pressure is reduced by chemical or physical removal of oxygen.
5. The method according to claim 1 , comprising measuring the partial oxygen pressure by means of an oxygen sensitive fluorescent dye.
6. The method according to claim 1 , wherein the method further comprises drying the seed to a moisture content which suspends radical development but does not result in loss of viability.
7. The method according to claim 6 , wherein the partial oxygen pressure and/or the partial carbon dioxide pressure is kept at a level that prevents radical emergence during drying.
8. The method according to claim 1 , further comprising storing the seed such that at least one of:
a) the partial oxygen pressure;
b) the moisture content of the seed; and,
c) the partial carbon dioxide pressure;
is kept at a level that prevents radical emergence.
9. The method according to claim 1 , wherein the seed is not tolerant to desiccation and wherein the method further comprises storing the seed at a partial pressure of oxygen and/or carbon dioxide that prevents radical emergence.
10. The method according to claim 9 , wherein the seed is stored under an atmosphere comprising more than 99% of at least one or more of nitrogen, a noble gas, carbon dioxide, CO, NO, NO 2 , N 2 O, ethylene, and ethanol.