کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5921488 | 1570988 | 2015 | 8 صفحه PDF | دانلود رایگان |
- Springtails survive prolonged exposure to extreme drought in soil.
- Euedaphic springtails remain hyperosmotic and active during drought.
- Accumulation of free amino acids has a significant role in osmoregulation.
- Alanine, proline and arginine are the most important amino acids in osmoregulation.
Springtails are closely related to insects, but they differ from these with respect to water balance, in particular because springtails are small and have high integumental permeability to water. Here we report a series of experiments addressing the dynamics of osmoregulation, water content and accumulation of free amino acids (FAAs) in three springtail species during exposure to a gradually increasing environmental desiccation simulating conditions in drought exposed soil. Folsomia candida and Protaphorura fimata (both living in the deeper soil layers; euedaphic species) were active throughout the 3Â week exposure, with the developing drought regime ending at â3.56Â MPa (the soil water activity at the permanent wilting point of plants is â1.5Â MPa) and remained hyperosmotic (having an body fluid osmolality higher than the corresponding environment) to their surrounding air. Sinella curviseta (living in upper soil/litter layers; hemiedaphic species) also survived this exposure, but remained hypoosmotic throughout (i.e. with lower osmolality than the environment). The body content of most FAAs increased in response to drought in all three species. Alanine, proline and arginine were the most significantly upregulated FAAs. By combining our results with data in the literature, we could account for 82% of the observed osmolality at â3.56Â MPa in F. candida and 92% in P. fimata. The osmolality of S. curviseta was only slightly increased under drought, but here FAAs were considerably more important as osmolytes than in the two other species. We propose that FAAs probably have general importance in drought tolerance of springtails.
Journal: Journal of Insect Physiology - Volume 82, November 2015, Pages 114-121