Ovule and Embryo Sac Development in Malus pumila L. cv. Cox's Orange Pippin, from Dormancy to Blossom

Ovule and embryo sac development in the flowers of Cox's OrangePippin apple (Malus pumila L.) were studied from dormancy topetal fall using both scanning electron and light microscopy.The relative timing was established between these developmentsand the external development of the flower bud and flower. Malus pumila L. cv. Cox's Orange Pippin, apple, Cox, SEM, ovule development, anatomy, histology     

Concordance between ecotypes and macroinvertebrate assemblages in Mediterranean streams

1. According to the guidelines of the European Water Framework Directive, assessment of the ecological quality of streams and rivers should be based on ecotype-specific reference conditions. Here, we assess two approaches for establishing a typology for Mediterranean streams: a top-down approach using environmental variables and bottom-up approach using macroinvertebrate assemblages.
2. Classification of 162 sites using environmental variables resulted in five ecotypes: (i) temporary streams; (ii) evaporite calcareous streams at medium altitude; (iii) siliceous headwater streams at high altitude; (iv) calcareous headwater streams at medium to high altitude and (v) large watercourses.
3. Macroinvertebrate communities of minimally disturbed sites ( n  = 105), grouped using UPGMA (unweighted pair-group method using arithmetic averages) on Bray–Curtis similarities, were used to validate four of the five ecotypes obtained using environmental variables; ecotype 5, large watercourses, was not included as this group had no reference sites.
4. Analysis of similarities ( anosim ) showed that macroinvertebrate assemblage composition differed among three of the four ecotypes, resulting in differences between the bottom-up and top-down classification approaches. Siliceous streams were clearly different from the other three ecotypes, evaporite and calcareous ecotypes did not show large differences in macroinvertebrate assemblages and temporary streams formed a very heterogeneous group because of large variability in salinity and hydrology.
5. This study showed that stream classification schemes based on environmental variables need to be validated using biological variables. Furthermore, our findings indicate that special attention should be given to the classification of temporary streams.     

Xylem Development in the Gynoecium of the Apple (Malm pumila L.) Cv. Cox's Orange Pippin K. A. D. *J. COSTA TURA{dagger}

Lignification of the xylem within the carpellary bundles ofapple flowers spreads acropetally from a point 900–1400µm below the base of the locules. At the same time, anotherwave of lignification spreads basipetally from a point justbelow the stigma. The acropetal spread at first progresses morequickly, but at later stages the number of lignified xylem elementsjust below the stigma increases rapidly, reaching a peak justas the flower opens. This increase is very localized and thenumber declines greatly within only 25 % of the stylar distancebelow the stigma. Lignification of the xylem in the bundlesserving other flower parts precedes that serving the gynoecium,and spreads basipetally from a point above the base of the locules Malus pumila, L., anatomy, apple, carpel, Cox's Orange Pippin, development, flower, gynoecium, pedicel, pistil, stigma, style, vasculature, xylem regenreation     

Xylem Development in the Gynoecium of the Apple (Malus pumila L.) Cv, Cox's Orange Pippin

Lignification of the xylem within the carpellary bundles ofapple flowers spreads acropetally from a point 900–1400µm below the base of the locules. At the same time, anotherwave of lignification spreads basipetally from a point justbelow the stigma. The acropetal spread at first progresses morequickly, but at later stages the number of lignified xylem elementsjust below the stigma increases rapidly, reaching a peak justas the flower opens. This increase is very localized and thenumber declines greatly within only 25% of the stylar distancebelow the stigma. Lignification of the xylem in the bundlesserving other flower parts precedes that serving the gynoecium,and spreads basipetally from a point above the base of the locules. Malus pumila L, anatomy, apple, carpel, Cox's Orange Pippin, development, flower, gynoecium, pedicel, pistil, stigma, style, vasculature, xylem