The potato eelworm hatching factor. 1. The preparation of concentrates of the hatching factor and a method of bioassay

The potato eelworm hatching factor. 3. Concentration of the factor by chromatography. Observations on the nature of eclepic acid

“…Production in 1944 was seriously affected by war damage at the station and ceased in the autumn of that year. The total amount of crude solid eluate obtained during the period was 218 g. with an average Relative Activity (R.A.) 9 (Calam, Raistrick & Todd, 1949), batches ranging from R.A. 4-13; under this arrangement then, we could extract about 12 g. crude solid per month, which, although small, was very much more than was available to us in our earlier work. The investigations described in this paper were all done on this material, referred to throughout as 'crude solid'.…”

“…The tomato plants were more easily grown indoors than potatoes, and gave a very active excretion. As work on the chemical nature of the active principle developed (Calam, Raistrick & Todd, 1949;Marrian, Russell, Todd & Waring, 1949), greater demands were made upon production of starting material for the investigation, and necessitated the growing of many thousands of tomato plants during a season. It became clear that if the scale of the work continued to expand a new source of root excretion, which could be easily and cheaply grown out of doors on a large scale, would be welcomed to replace the growing of tomato plants under glass.…”

“…Although the factor evidently had a comparatively low molecular weight, the small amount of it present in tomato root leachings, coupled with its great instability, made chemical investigation extremely difficult. Fortunately, larger supplies became available through the generous help afforded by the Agricultural Research Council, which arranged for the growing and leaching of tomato plants on a large scale by essentially the method described in Part 1 (Calam, Raistrick & Todd, 1949) to be carried out at the Experimental Station, Cheshunt. There a stock ofsome 150,000 tomato plants was maintained under glass during the period May 1943 to September 1944.…”

Production of Potato Cyst Nematode Hatching Stimulus by Hairy Root Cultures of Tomato

“…Large scale production of the hatching stimulus is of interest, because the stimulus can be used as an agricultural drug against the cyst nematode. 6 ) If the hatching stimulus is applied to infected soil in the absence of host plants, the larvae would emerge but soon die in the absence of a suitable host. The biology of these cyst nematodes has been described.…”

Diapause in the nematodeGlobodera pallida

“…Various suggestions have been made to explain why some encysted eggs do not hatch, including the presence of inhibiting substances produced as a result of metabolic activities of the juveniles within the eggs during process of hatching [Ellenby, 1946], oxygen deficiency in the hatching medium [Wallace, 1959], seasonal variation [Calam et al, 1949] and genetic inheritance [E1-Shatoury, 1978]. Shepherd and Cox [1967] and Oostenbrink [1967] considered that G. rostochiensis eggs which failed to hatch under optimum conditions were in diapause, and they compared the phenomenon with that found in insects.…”