A New Type of Specialized Cell in the Gynoecium of Ornithogalum caudatum (Liliaceae) with Notes on Specialized Cells in Carpels of Other Taxa

Idioblasts differentiate acropetally and centrifugally fromthe base of the ovary and eventually are found throughout thegynoecium Differentiation begins with an increase in cytoplasmicgranularity and culminates with the formation of dense cytoplasmicmasses, arms, and rings which stain for protein, carbohydrateand RNA Idioblastic cell contents eventually are cataboltzedand the cells are emptied of all contents during seed maturationIt is proposed that these cells function as specialized storagecells. Ornithogalum caudatum, carpels, gynoecium, idioblasts, specialized cells     

Evaluation of Accuracy and Precision of Downing Population Reconstruction

ABSTRACT Downing population reconstruction uses harvest-by-age data and backward addition of cohorts to estimate minimum population size over time. Although this technique is currently being used for management of black bear (Ursus americanus) and white-tailed deer (Odocoileus virginianus) populations, it had not undergone a rigorous evaluation of accuracy. We used computer simulations to evaluate the impacts of collapsing age classes and violating the assumptions of this technique on population reconstruction estimates and trends. Changes in harvest rate or survival over time affected accuracy of reconstructed population estimates and trends. The technique was quite robust to collapsing age classes as far as 3+ for bears and deer. This method would be suitable for estimating population growth rate (λ) for populations experiencing no trend in harvest rate or natural mortality rate over time. Our evaluation showed Downing population reconstruction to be a potentially valuable tool for managing harvested species with high harvest rates and low natural mortality, with possible application to black bear and white-tailed deer populations.     

Calcium Oxalate Raphide Crystals and Crystalliferous Idioblasts in the Carpels of Ornithogalum caudatum

Crystalliferous idioblasts commonly are found in groups of twoor three cells in the peripheral region of the carpels Crystals,composed of calcium oxalate, usually are m well-organized bundleswhich develop within a matrix of protein and carbohydrate inthe vacuole of each idioblast The matrix occurs around and betweenindividual crystal chambers and contains spheres and tubules5.4 nm in diameter The matrix changes in character and locationwith age Crystals form within their own individual chambers,each comprised of a series of lamellae The number of lamellaeis variable The innermost lamella is different from the othersin that it is apparently continuous The other lamellae are platelikeand superficially resemble successive periderms. The lamellaemay begin and/or terminate abruptly or they may anastamose Eachlamella is composed of chains of spheres about 6 1 nm in diameterand is separated from adjacent lamellae by tubules 5.4 nm indiameter Both the crystals and slime body are absorbed duringlater stages of carpel maturation. Ornithogalum caudatum Ait carpel, calcium oxalate, idioblasts, ultrastructure