Allelopathic interactions between the macrophyte Egeria densa and plankton (alga, Scenedesmus acutus and cladocerans, Simocephalus spp.): a laboratory study
Por:
Espinosa-Rodriguez, Cristian A., Rivera-De la Parra, Ligia, Martinez-Tellez, Aurora, Gomez-Cabral, Gisela C., Sarma, S. S. S., Nandini, Sarma
Publicada:
1 ene 2016
Resumen:
Allelopathic interactions between macrophytes and zooplankton are
important to understand the plankton dynamics in shallow waterbodies.
Egeria densa is a native, perennial, submerged macrophyte in the
tropical and subtropical zones of South America. It has been introduced
to Central and North America and is now common in many Mexican lakes.
This macrophyte produces chemical substances that negatively affect some
phytoplankton species. However, it is not clear how zooplankton species
adapt different life history strategies in the chemical presence of this
macrophyte. Here, we tested the direct and indirect effects of
allelochemicals released by E. densa on the population growth of
Scenedesmus acutus and on the demographic variables of three species of
Simocephalus, S. exspinosus, S. serrulatus and S. mixtus (via alga
exposed to the macrophyte allelochemicals). To quantify the effect of E.
densa on S. acutus we set up four treatments: control, artificial
Egeria, natural Egeria and allelochemicals from Egeria. To test the
allelochemical effects on Simocephalus species, we compared four
treatments: Control, indirect effect (using S. acutus grown on
Egeria-allelochemicals), direct effect (using Egeria-conditioned medium)
and together with direct and indirect effects. Scenedesmus had the
highest cell density in the presence of allelochemicals from Egeria,
followed by controls. The specific algal growth rate (mu) between
control and allelochemicals treatment was not significant (P<0.05).
However, the mu of alga in the presence of artificial or natural Egeria
was significantly lower than in controls or in treatments involving
allelochemicals. The age-specific survivorship of the three cladoceran
species was longer in treatments containing Egeria-conditioned medium.
Cladocerans receiving Egeria conditioned-medium and algae cultured on
macrophyte-allelochemicals also had a longer survivorship. Daily
fecundity of S. serrulatus increased after reaching mid-age while S.
expinosus and S. mixtus showed continuous reproduction starting from the
first week. In general, Egeria-allelochemicals enhanced the age-specific
reproductive output for all the three cladoceran species. The average
lifespan of the three Simocephalus varied from 17 to 46 days, depending
on the cladoceran species and treatment. S. serrulatus had lower
lifespan compared to other two cladoceran species. For the three
species, lifespan significantly increased in treatments containing
macrophyte-conditioned medium + algae grown on the
plant-allelochemicals; also under these conditions, both gross and net
reproductive rates were significantly enhanced. This stimulatory effect
was also evident in generation time (about 50% higher). The rate of
population increase ranged from 0.23 to 0.38 per day for the three
tested Simocephalus species but there were no significant differences
(P>0.05) among treatments. Our results suggest that the biological
activity as well as physical structure of E. densa had negative effects
on S. acutus population growth but had stimulatory effects on the
demography of Simocephalus.
Filiaciones:
Espinosa-Rodriguez, Cristian A.:
Univ Nacl Autonoma Mexico, Postgrad Programme Marine Sci & Limnol, Ciudad Univ,Ave Univ 3000, Mexico City 04510, DF, Mexico
Rivera-De la Parra, Ligia:
Univ Nacl Autonoma Mexico, Postgrad Programme Biol Sci, CU, Postgrad Studies Bldg, Mexico City 04510, DF, Mexico
Martinez-Tellez, Aurora:
Univ Nacl Autonoma Mexico, Postgrad Programme Marine Sci & Limnol, Ciudad Univ,Ave Univ 3000, Mexico City 04510, DF, Mexico
Gomez-Cabral, Gisela C.:
Univ Nacl Autonoma Mexico, Postgrad Programme Marine Sci & Limnol, Ciudad Univ,Ave Univ 3000, Mexico City 04510, DF, Mexico
Sarma, S. S. S.:
Univ Nacl Autonoma Mexico, Div Res & Postgrad Studies, Lab Aquat Zool, Campus Iztacala,Ave Barrios 1, Los Reyes Iztacala 54090, Tlalnepantla, Mexico
Nandini, Sarma:
Univ Nacl Autonoma Mexico, Div Res & Postgrad Studies, Lab Aquat Zool, Campus Iztacala,Ave Barrios 1, Los Reyes Iztacala 54090, Tlalnepantla, Mexico
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