for January, 1921 



437 



much longer in some sections of the country than in others, and 

 the part which the environment surrounding a seed plays in its 

 germinating power is of much more importance than is generally 

 supposed. 



\Vhile species differ in a decided manner with respect to the 

 length of time in which vitality is maintained under what may 

 be termed artificial conditions, and this is true however ideal these 

 conditions may be, there is no doubt that the life of a seed is 

 dependent upon many factors, but the one of the greatest impor- 

 tance governing the life of seeds artificially kept is dryness. 

 Probably the best method of keeping seeds in small (juantities 

 is to have them perfectly dry and place them in an equally dry 

 fruit jar and screw down the top upon a rubber ring so that 

 the jar remains air-tight. In this way peas, beans, radish, cab- 

 bage, melon, and others allied to these, may be kept over, but it 

 is not worth while doing so with parsnip, carrot, onion, lettuce 

 and herbs generally, as these latter soon lose their vitality. With 

 flowers, new seed is invariably advisable. In all cases a germi- 

 nation test should be made of kept over seeds before sowing 

 time. 



While the entire round of plant life is wonderfully intricate 

 and extremely interesting, there is no phase of that life more so 

 than seed germination, unless we class as still more wonderful 

 the fact of a plant transferring its life to its seed, which seed, 

 while to all appearance dead, contains under normal conditions, 

 a living germ. This small germ, in some cases invisible to the 

 naked eye, contains within it all the characters and potentialities 

 of its parents. While this germ can. under certain possibilities, 

 be easily destroyed, it is at the same time under some possibilities 

 difficult to kill. When perfectly dry it is not killed under a 

 temperature as high as 212° F., and it will also withstand a tem- 

 perature as low as 70° F. below zero. The seed is practically a 

 perfect plant in an embryonic state, and it is so designed that it 

 will survive conditions which would be fatal to the plant itself. 



Generally, seeds which are buried deeply in the ground retain 

 their vitality for a long period, in fact, much longer than under 

 any method at present devised for keeping them artificially. 

 Reliable evidence has proved that both red and white clover 

 seeds, amongst others, will germinate after being buried for 

 thirty years at a depth of three or four feet. 



Neither by the use of the most powerful microscope, nor by 

 the most delicate chemical analysis, can we determine whether 

 the embrj'o of a given seed possesses any vitality or not. The 

 vitality of seeds can only be determined by a germinating test, 

 which test may be made in the natural way by sowing seeds in 

 the soil, which, provided the seeds are sown under proper con- 

 ditions, is the most useful method of testing; or by means of 

 several artificial methods, such as placing the seeds between 

 two pieces of flannel or cloth kept continually moist in a warm 

 atmosphere, or by placing thera in a laboratory seed-tester. If 

 one sends a sample of seed to their State Experimental Station 

 for testing, they will sooner or later receive word that the seed 

 germinated so much per cent, which means that a certain num- 

 ber of seeds were viable inasmuch as the embryos they contained 

 had sufficient life to start into growth, or sprout. Properly con- 

 ducted laboratory tests are carried out under ideal conditions as 

 regards temperature and moisture, and such tests will always 

 give a liigher percentage of germination than is generally possible 

 when the seed is sown in the ordinary way in the soil. Further, 

 in nearly, if not quite, all samples of seeds there are always some 

 in which the embryo, while having sufficient vitality to start into 

 growth by sprouting, is not sufficiently strong to complete the act 

 of germination, in other words, to produce a plant. For this 

 reason, as well as for others which will be apparent as we pro- 

 ceed, we inay calculate that from a sample of seed which under a 

 laboratory test will show a germination of 80 per cent, will not 

 give more than 40 per cent wliich will produce perfect plants 

 when sown in the ground under ordinary conditions. Obviously 

 the better the entire environment surrounding seeds after being 

 placed in the soil the greater will be the number of plants pro- 

 duced. It is possible for even viable seeds to be sown with little 

 or no germination resulting. When this happens, the blame is 

 generally put upon the seedsman, while the chances are that the 

 seeds which failed to come up were perfectly good, and that the 

 reason for their not doing so should be sought for in other 

 directions. 



The germ or embryo of a good seed is in a state which may be 

 likened to deep sleep: its life is, as it were, arrested, suspended, 

 but under the stimulus of a favorable environment, it awakens, 

 comes out from its coverings, gathers strength from the food 

 stored up for it within the seed, and becomes a perfect plant, part 

 of which appears above ground, while the other part ramifies in 

 the soil searching for food. 



A sufficiency of moisture, heat and oxveen are tlie determining 

 causes which bring about the starting of germination, which 

 causes are only eflfectivc when co-operating together. .Ml of the 

 food iTialcrials in seed.; undergo certain changes during germina- 



tion. The chief agents bringing about these changes are ferments, 

 whicn ferments are started into action when hi the embryo, or 

 in other words, at the initial starting point of germination. When 

 seeds germinate the starch is changed into soluble dextrose bodies 

 before it is utilized by the plantlct. This change is brought about 

 by the action of ferments, particularly diastase which is found in 

 all seeds. As germination progresses, some of the starch is 

 oxidized and heat is produced, and under all conditions of soil 

 temperature, the temperature of a germinating seed is higher 

 than it was before germination started. 



In gertnination, the fats are first broken up into fatty acids, 

 and then converted into starch and other soluble carbohydrates, 

 as dextrine and sugars. It is estimated that 887 parts' of fat 

 will produce 1,700 parts of starch simply by the addition of 

 oxygen from the air. In the oil seeds about twice the amount of 

 reserve food is stored up in the same space in the form of fat as 

 in other seeds in the form of starch. 



The proteid compounds of seeds, which are mainly present in 

 insoluble forms, are rendered soluble by ferment action. Some 

 of the soluble proteids are broken down into a condition which 

 enables them to be transported through the plant tissues and used 

 as building material. After passing through the cell walls, these 

 compounds are reconstructed into proteids. 



As a whole, the changes taking place in the seed during germi- 

 nation are the same as those w^hich occur in the digestion of food 

 in the animal stomach. In the germination process, starch, fat and 

 proteids are changed by ferment action into soluble forms. The 

 diastase and peptonizing ferments are aniong the most active in 

 producing the chemical changes in both germination and digestion 

 processes. 



As above mentioned, the co-operative action of moisture, heat 

 aiid oxygen is necessary before germination can begin. The action 

 of moisture to soften the seed, which, when placed in the soil, is 

 in an absolutely dry condition, must take place first, and seeds 

 have to be nearly, or quite, saturated with water and the seed- 

 case soft enough for the sprout to break through, before they 

 will begin to germinate. The unfolding and expansion of the 

 embryo is largely due to the great absorptive power possessed 

 by the protoplasm within the cells. When water is obtainable, 

 this power causes all parts of the embryo to be constantly satu- 

 urated. and the clastic cell-walls are distended until they are 

 like minute inflated bladders. The pressure thus set up aids in 

 unfolding the different parts from their resting place within 

 the seed-case, and enables the plantlet to burst the covering of 

 the seed. Of course, further growth by cell division soon takes 

 place. 



In botanical language the outer coverings of seeds — which may 

 be one or more — are given different names according to their 

 exact part in the seed's make-up, and the word seed-case can be 

 taken to include all the various botanical terms used to designate 

 the outer covering of seeds. Seeds differ considerably in the 

 hardness of their coverings, and some take a very long period 

 before the softening process is complete. Some seeds of this 

 character may lie in the ground for weeks, months, or even years, 

 without swelling, and plant raisers have adopted many methods 

 for hastening the process ; such as, stratification in moist sand kept 

 just above freezing point all the Winter, and then sowing the 

 seed in the Spring; in some cases soaking in hot water has good 

 effect. Seeds with a hard shell, as with nuts, peach stones, and 

 such like, the shells are first broken, or the same thing occurs 

 in X'ature by the action of frost when they are planted in the 

 Fall, in the latter case germination does not take place until the 

 following Spring. The germination of seeds w-ith hard cases, 

 like canna, is hastened by filing a groove through the case. 



While all the ordinary garden seeds will, under the usual soil 

 conditions as regards inoisture, absorb sufficient water, some 

 require a much longer period than others, and with the latter, 

 parsley, for instance, germination can be hastened by soaking 

 the seeds before sowing in warm water not exceeding 100° F. 

 Care should be taken not to soak the seeds too long, they should 

 be taken out of the water as soon as swollen and sown imme- 

 diately. It is usually sufficient to place the .seeds in water over- 

 night and they will have absorbed sufficient water by the fol- 

 lowing morning. It is also neccssarj- to have the soil conditions 

 right, otherwise the sowing of soaked seeds may do more harm 

 than good. 



After seeds have absorbed sufficient moisture, the next step in 

 starting germination is a high enough temperature, and the 

 seeds of some species and varieties of the same species 

 will germinate at a lower temperature than others. It is inter- 

 esting to note that the absorption of water will not alone start the 

 necessary biological and chemical changes in seeds ; these do not 

 begin until the embryo commences its activity. Unless the tem- 

 perature is high enough for this activity to start within a com- 

 paratively short time after the seed is saturated, it rots. 

 (Continued on page 4401 



