Fluoride injury of wheat roots and calcium nutrition

Wheat roots growing in a saturated atmosphere were treated 5min with various concentrations of calcium sulfate and the growthresponse recorded. Roots treated with optimum calcium followedby a delayed treatment with inorganic fluoride, or the reversesequence of treatments, caused responses very similar to thoseresulting from calcium deficiency. Potassium oxalate, sodiumethylenediaminetetraacetate and sodium monofluoroacetate allcaused responses that corresponded to various states of calciumdeficiency. Results suggest but do not confirm that the majoradverse effects of inorganic fluoride are the result of precipitationand depletion of available calcium in cells. Response of monofluoroacetatemight also in part be attributed to its release of inorganicfluoride in vivo. Results also indicate a depletion of a criticalconcentration of calcium from the elongation zone of roots bya 5-min treatment in any solution low in calcium will initiatechanges which cannot be reversed by treatment of calcium, andwhich will result in tissue damage. The meristematic cells areless sensitive. ¹This research was supported in part by Public Health ServiceGrant AP 00276-01 from the Division of Air Pollution. Journalpaper no. 761. Utah Agricultural Experiment Station. ²Present address: Department of Water Science and Engineering,University of California, Davis. (Received April 19, 1969; )     

Foliar form influences ovipositional behaviour of the onion fly

ABSTRACT. When presented with dishes containing a range of 'foliar' shapes, the onion fly, Delia antiqua (Meigen), laid the most eggs around narrow (4 mm) vertical cylinders. Response to cylinders diminished when their diameter was increased or decreased, when cylinder height was reduced to less than 2 cm, and when cylinder/substrate angle deviated from 90. Differences in egg numbers on stimulatory and non-stimulatory forms reflected primarily differences in post-alighting pre-ovipositional behaviours. Females alighting on narrow vertical cylinders initiated and completed stem runs rapidly and without interruptions, and frequently went on to probe and oviposit. Females alighting on other shapes, or larger, smaller, or non-vertical cylinders, either did not initiate or did not complete stem runs, or did not go on to probe after completing a stem run. Such females rarely oviposited. Possible causes of such examining behaviours are discussed.     

Cellular Mechanisms of Organic Anion Transport in Crustacean Renal Tissue

Decapod Crustacea appear to utilize two overall strategies forexcretion of anionic wasteproducts and xenobiotics. One strategyutilizes a potent renal secretory system; the other utilizesboth modest renal secretion and strong gut secretion (possiblyaided by midgut gland conjugation). In crabs, the level of participationof the renal system in overall excretion is primarily determinedbythe location of an anion pump and a carrier protein. The bladder of Cancer borealis, which strongly secretes themodel organic anion, p-aminohippuric acid (PAH), has a serosalorganic anion pump and a luminal facilitated carrier. The bladderof Cancer trroratus, which reabsorbs PAH from bladder urine,has a luminal organic anion pump and a serosal facilitated carrier.     

Gobies from Rhodes and the systematic features of Zebrus zebrus (Teleostei: Gobiidae)

The gobiid fishes of Rhodes are listed from past records and a recent collection made in 1970. Problems of identification and selected diagnostic features are described and illustrated. Additions to the species-list include Chromogobius quadrivittatus, Ch. zebratus levanticus, Millerigobius macrocephalus, and Zebrus zebrus, although a number of productive habitats remain to be explored. The genus Zebrus is redefined, with osteological characters, and its single species, Z. zebrus, redescribed. A comparison with M. macrocephalus tabulates features which may be used to distinguish the two taxa.     

Swimming in mantids

The initiation, form of leg strokes and minimal requirements for swimming in Sphodromantis lineola are described.