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GERMINATION OF SEEDS OF WATER PLANTS 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 104 



William Crocker 



Various botanists have noticed peculiarities in the germination of 

 the seeds of water plants. Muller'' found that the seeds of Eich- 

 hornia and Heteranthera do not germinate without first being desic- 

 cated, and LuDWiG^ demonstrated this for the seeds of Mayaca 

 fluviatilis. In commenting upon this Peeffer says:^ ^'Nor is it 

 certain whether Braun and Muller are correct in assuming that 

 previous drying is essential for the further development of Chlamy- 

 domonas or for the germination of the seeds mentioned." Dr. 

 Land, of this laboratory, informed me in the autumn of 1906 that he 

 had made various attempts to secure seedlings of Sagittaria and 

 Alisma for class use, but had always failed except in one trial with 

 ^agittaria. In that case a number of seeds grew after being left for 

 a long period on wet soil in a hot greenhouse. At that time I began 

 looking into the cause for the failure to germinate and had arrived at 

 the main conclusion of this paper when an article by Fischer'^ 

 appeared on the subject. 



The main points of Fischer's paper may be stated briefly: The 

 seeds of Alisma Planiago, Potamogeton lucens, P. pectinaitis, Hip- 

 piirus vulgarisy Polygonum amphibium, Scirpus lacustrls, 5. maritimus, 

 Sagittaria platyphylla, S. sagitti folia, and Sparganium ramosum may be 

 kept for years in water that is free from fermentation without germi- 

 nating. If fermentation is set up in the water, germination soon 

 begins. Germination can also be brought about, especially in 

 Sagittaria, by subjecting the seeds to the action of bases and acids. 

 Fischer holds that the H"^ or OH" ions act as stimulants on the 



I See Ltjdwig's article below. 



Keimfahigkeit 



einiger Wasserpflanzen. Biol. Centralbl. 6:299, 300. 1886. 



3 Pfeffer, W., Physiology of plants (Eng. ed.) 2:210. 1903. 



4 Fischer, Alfred, Wassertoff- unci Hydroxylionen als Keimungsreize, Ber. 



Deutsch. Bot. Gesells. 15:108-122. 1907, 

 375] 



[Botanical Gdizettey vol. 44 



