The Postclassic to Spanish-Era Transition in Mesoamerica

The Postclassic to Spanish-Era Transition in Mesoamerica . Susan Kepecs and Rani Alexander, eds. Albuquerque: University of New Mexico Press, 2005. 260 pp.     

Simplified heavy metal staining techniques demonstrated with Fast Plant leaf tissue

Fast Plant(Brassica rapa,Cruciferae)leaf tissuefixed in glutaraldehyde-acrolein and post-fixed in os-mium,was examined for response to several easily-prepared heavy metal stains.Lead and uranium,separately and in combination,gave typical resultsacross the spectrum of cell organellets.As a single stainfollowing osmium,bismuth produced images seeminglyequivalent to lead and uranium.Phosphotungstic acidproduced very good membrane delineation but produceda washed-out background image similar to that from leadstaining.Carbohydrate compounds were especiallyresponsive to ruthenium;the cytoplasm and the matrixof all organelles were also stained very well.Theprocedures were no more demanding than traditionalstaining methods and may be easily used in research andteaching.Fast Plant materials are a reliable,quick andeasy source of living material.     

The Cliff Swallow Bug Oeciacus vicarius (Hemiptera: Cimicidae) in Florida: ectoparasite implications for hole-nesting birds

In May 1988, ten juvenile birds, not yet ready to fledge, jumped to their death from a colony of the purple martin, Progne subis near Okeechobee City, Florida. The martin house and nestlings were found to be infested with ectoparasitic Oeciacus vicarius Horvath, the cliff swallow bug, not previously reported from Florida. This ectoparasite infestation apparently led to early abandonment of two houses by the adult martins. Oeciacus vicarius therefore represents a possible threat to all hole-nesting birds.     

IMPACT OF MICROWAVE BLANCHING ON THE FLAVOR OF ROASTED PEANUTS

Microwave blanching of peanuts was proposed as an attractive alternative to traditional techniques of blanching, because of energy and time savings. However, the occurrence of a processing‐related off‐flavor has been reported. This study examined the effect of processing factors during microwave blanching on the MC and sensory characteristics of the peanuts. The peanuts reached a range of internal temperatures during microwave blanching treatments between 4 and 11 min. A total offnote attribute was introduced to the peanut lexicon and was used successfully to differentiate the effects of microwave treatments. The microwave‐associated off‐flavor was related (but not identical) to cardboardy/stale flavor, and was related inversely to the positive flavor attributes roasted peanutty, sweet aromatic and sweet taste. Peanuts reaching the highest internal temperatures and greatest moisture losses during blanching exhibited the most total offnote flavor; however, temperatures as high as 113C did not produce significantly increased total offnote intensity.     

Puccinellia tenuiflora maintains a low Na+ level under salinity by limiting unidirectional Na+ influx resulting in a high selectivity for K+ over Na+

Puccinellia tenuiflora is a useful monocotyledonous halophyte that might be used for improving salt tolerance of cereals. This current work has shown that P. tenuiflora has stronger selectivity for K⁺ over Na⁺ allowing it to maintain significantly lower tissue Na⁺ and higher K⁺ concentration than that of wheat under short- or long-term NaCl treatments. To assess the relative contribution of Na⁺ efflux and influx to net Na⁺ accumulation, unidirectional ²²Na⁺ fluxes in roots were carried out. It was firstly found that unidirectional ²²Na⁺ influx into root of P. tenuiflora was significantly lower (by 31–37%) than in wheat under 100 and 150 m m NaCl. P. tenuiflora had lower unidirectional Na⁺ efflux than wheat; the ratio of efflux to influx was similar between the two species. Leaf secretion of P. tenuiflora was also estimated, and found the loss of Na⁺ content from leaves to account for only 0.0006% of the whole plant Na⁺ content over 33 d of NaCl treatments. Therefore, it is proposed that neither unidirectional Na⁺ efflux of roots nor salt secretion by leaves, but restricting unidirectional Na⁺ influx into roots with a strong selectivity for K⁺ over Na⁺ seems likely to contribute to the salt tolerance of P. tenuiflora .     

Confronting assumptions about spontaneous autogamy in populations of Eulophia alta (Orchidaceae) in south Florida: assessing the effect of pollination treatments on seed formation,seed germination and seedling development

The breeding system of the terrestrial orchid Eulophia alta was investigated in south Florida where it has previously been reported as an auto‐pollinated species. The effect of breeding system on seed viability and germinability and seedling development was also investigated. Incidences of spontaneous autogamy in E. alta were rare at the study site, resulting in only 7.1% of observed flowers forming capsules. In addition, hand pollination resulted in significantly greater capsule formation when flowers were subjected to induced autogamy (46.4%), artificial geitonogamy (64.3%) and xenogamy at both short (pollen source 10–100 m away; 42.9%) and long (pollen source > 10 km away; 67.9%) distances. Pollen source had little effect on seed viability and germinability or seedling growth rates. However, seed resulting from spontaneous autogamy developed more slowly than seed originating from the other treatments. These data indicate that spontaneous autogamy is rare in E. alta and that naturally forming capsules may be the result of unobserved pollination events. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161 , 78–88.     

Water uptake and hydraulic redistribution across large woody root systems to 20 m depth

Deep water uptake and hydraulic redistribution (HR) are important processes in many forests, savannas and shrublands. We investigated HR in a semi‐arid woodland above a unique cave system in central Texas to understand how deep root systems facilitate HR. Sap flow was measured in 9 trunks, 47 shallow roots and 12 deep roots of Quercus, Bumelia and Prosopis trees over 12 months. HR was extensive and continuous, involving every tree and 83% of roots, with the total daily volume of HR over a 1 month period estimated to be approximately 22% of daily transpiration. During drought, deep roots at 20 m depth redistributed water to shallow roots (hydraulic lift), while after rain, shallow roots at 0–0.5 m depth redistributed water among other shallow roots (lateral HR). The main driver of HR appeared to be patchy, dry soil near the surface, although water may also have been redistributed to mid‐level depths via deeper lateral roots. Deep roots contributed up to five times more water to transpiration and HR than shallow roots during drought but dramatically reduced their contribution after rain. Our results suggest that deep‐rooted plants are important drivers of water cycling in dry ecosystems and that HR can significantly influence landscape hydrology.