|De invloed van de fysiologische stress-situaties verbonden aan een wisselend zoutgehalte, op de ontwikkeling en groei van de vrijlevende nematode Panagrellus silusiae (De Man, 1913) Goodey, 1945|
Gysels, H.; Tavernier-Bracke, E. (1975). De invloed van de fysiologische stress-situaties verbonden aan een wisselend zoutgehalte, op de ontwikkeling en groei van de vrijlevende nematode Panagrellus silusiae (De Man, 1913) Goodey, 1945. Natuurwet. Tijdschr. 57(1): 15-37
In: Natuurwetenschappelijk Tijdschrift. L. Walschot/Natuur- en Geneeskundige Vennootschap: Gent. ISSN 0770-1748, more
Animal growth; Biological development; Biological stress; Osmotic pressure; Nematoda [WoRMS]; Panagrellus silusiae (De Man, 1913) Goodey, 1945; Marine; Brackish water
|Authors|| || Top |
- Gysels, H.
- Tavernier-Bracke, E.
Changes in salt content of the culture (barley powder made up with different concentrations of sea-water and brackish water) did not lead to any considerable influence on growth or development, provided that the changes varied between 1 and 15 g NaCl/l. Table I represents the development in mass cultures, indicated in number of days; table II shows the survival; table III the reproduction in micro-cultures, also in days. However, cultures prepared with higher concentrations of sea water (resp. mesohaline, 18 g NaCl/l and polyhaline, 30 g NaCl/l), proved to be unfavourable media : all measures decrease with increasing salt content, except body-length, body-width and oesophageal length of females in brackish water (table IV). The considerable decreases of the eelworms could be demonstrated to be significant, by using the test U =x1-x2/E : the differences are significant on the 95 % level, if the quotient is greater than 1.96. This is the case for all of them, except for the body and oesophagus length of females cultured in fresh and brackish water; among the body width the significance lies on the limit. It is discussed that the variability of all the measurements obtained from eelworms cultured in fresh water, i. e. in normal conditions, is much greater than with measurements obtained under circumstances of a higher osmotic pressure. This is clear for a sample homogeneous in age, but it is still more pronounced when the eelworms, reared under normal fresh water conditions, are sampled from cultures of different age (e.g. 5 and 10 days). As a matter of fact all these phenomena lead to some important consequences with regard to the growth dispersion curves of the populations, the nematological indices, the course of the allometric growth etc.; they will be discussed in a more detailed paper.