Inheritance of tolerance to leaf iron deficiency chlorosis in tomato

By using two tomato genotypes, "227/1" (Fe chlorosis susceptible) and "Roza" (Fe chlorosis tolerant), and their reciprocal F-1, F-2 and BC1 generations, the inheritance of tolerance to leaf Fe deficiency chlorosis of Roza was studied. Plants were grown in a nutrient solution and subjected to 2.0 x 10(-6) M Fe EDDHA and 10 mM NaHCO3 to induce Fe deficiency stress by stabilization of pH to 7.8-8.2. A rating scale of 1-3 for chlorophyll was used and both monogenic and polygenic inheritance hypotheses were tested. Better responses to Fe deficiency, as measured by SPAD meter values, were obtained from the cross "Roza x 227/1" than from the reciprocal cross. Data from F-2 and BC1 suggest Fe chlorosis tolerance of Roza is to be controlled by polygenic loci with a relatively high additive effect

Asociaciones de quistes de dinoflagelados de agua salobre a dulce de la formacion la colonia (Paleoceno?), Noreste de Patagonia, Argentina

A palynological analysis of the section of La Colonia Formation exposed at Estancia San Miguel yielded conspicuous assemblages of organic-walled dinoflagellate cysts (dinocysts) and green algae. The monotypic palaeoperidinioid dinocyst assemblage of ?Ginginodinium sp. in the basal beds of this section indicates low-salinity water conditions in a restricted shallow marine paleoenvironment. The green-algae-dominated assemblages together with specimens of ?Morkallacysta spp., Dinocysts type P and ?Vesperopsis sp. recorded in the middle and upper part of the San Miguel section indicate brackish to freshwater and freshwater depositional conditions, respectively. The changes in the composition of the palynological assemblages, in agreement with the analysis of the sedimentary facies, reflect a salinity-drop in the water bodies and a progressive upward-shallowing trend. The occurrence of specimens of the neritic open marine Cribroperidinium spp., Apteodinium sp., Circulodinium sp. and Areoligera sp. cf. A. circumsenonensis Fensome et al. is here considered as reflecting contemporaneous transported material from the adjacent shelf. The marine part of the La Colonia Formation is associated to Late Cretaceous and Paleocene ages. Nevertheless, palynomorphs together with a stratigraphical criterion suggest an age non older than Paleocene for the deposits of the unit at the San Miguel section