ALBERT

Notes: A new species of marine interstitial ciliate, Tracheloraphis primitarum sp. n., is described from intertidal sands (160-200-μm medium grain size) along the Northwest Atlantic coast. Living specimens are not transparent under incident light, 0.4-0.9 mm in length, and are characterized by an elongated body, bulbous anterior and rounded posterior regions. Cytostome is simple without a cleft on the lip. Protargol silver impregnation shows 18-29 longitudinal kineties. The glabrous zone is very narrow, 6-7 μm wide, and corresponds to the area occupied by one kinety and two interkinetal spaces. Ten to fifteen kineties terminate against the glabrous zone. Interkinetal extrusomes are present. The nuclear apparatus is a single centrally-placed nuclear group that consists of three large irregular macronuclei and 2-3 micronuclei; these are either clustered or encapsulated.

Notes: The Graph Theorist, GT, is a system that performs mathematical research in graph theory. From the definitions in its input knowledge base, GT constructs examples of mathematical concepts, conjectures and proves mathematical theorems about concepts, and discovers new concepts. Discovery is driven both by examples and by definitional form. The discovery processes construct a semantic net that links all of GT's concepts together.Each definition is an algebraic expression whose semantic interpretation is a stylized algorithm to generate a class of graphs correctly and completely. From a knowledge base of these concept definitions, GT is able to conjecture and prove such theorems as “The set of acyclic, connected graphs is precisely the set of trees” and “There is no odd-regular graph on an odd number of vertices.” GT explores new concepts either to develop an area of knowledge or to link a newly acquired concept into a pre-existing knowledge base. New concepts arise from the specialization of an existing concept, the generalization of an existing concept, and the merger of two or more existing concepts. From an initial knowledge base containing only the definition of “graph,” GT discovers such concepts as acyclic graphs, connected graphs, and bipartite graphs.

Notes: Differences between the mouse Ly5a and Ly5b alleles can be distinguished on the basis of polymerase chain reaction (PCR)-restriction enzyme analysis and differential monoclonal antibody reactivities. To more precisely map the Ly5 gene on the mouse chromosome 1, analytical DNA and protein tests were performed on recombinant inbred strains of mice prepared from SJL/J (Ly5a) and B ALB/cke (Ly5b) progenitor strains. Each recombinant inbred strain was characterized to determine whether it carried the Ly5a or Ly5b allele. Both assays, DNA-PCR and protein-immunofluorescence, yielded identical results for each strain examined. Placement of the Ly5 gene with respect to other characterized markers of mouse chromosome 1 for these recombinant inbred mouse strains shows a gene order of Idh-1.Ity:Pep3:/Ly5, CfhJ.

Notes: Abstract Salt-stressed plants often show Ca deficiency symptoms. The effects of NaCl salinity (1 to 150 mol m-3) and supplemental Ca (10 mol m-3) on Na and Ca transport in barley (Hordeum vulgare L.) and their relationship to growth were investigated. The adjustment of Na and Ca transport was investigated by examining young seedlings exposed to short-term (immediate) and long-term (7 d) exposure to salinity. When the plants were exposed to long-term treatments of salinity, the rate of sodium accumulation in roots was approximately 10 to 15% of short-term treatments. No significant adjustment in the transport to the shoot was observed. Rates of tracer (22Na) transport were compared to calculated rates based on relative growth rates and tissue element concentrations. Comparisons between measured tracer and calculated rates of transport indicate that 22Na transport may underestimate transport to the shoot because of dilution of the tracer in the root cytoplasm. Calcium uptake showed only minor adjustment with time. Measured rates of tracer transport to the shoot correlated well with calculated values. The transport and tissue concentrations of Na were significantly affected by supplemental Ca. Calcium transport and tissue concentrations were markedly inhibited by salinity. Supplemental Ca increased Ca transport and accumulation at all NaCl treatments above that of control plants without supplemental Ca. Salinity inhibited plant growth at 150 mol m -3NaCl, but not at 75 mol m-3.Supplemental Ca significantly improved root length but not fresh weight after 7d of salinity, although differences in fresh weight were detected after 9d. There were significant Na-Ca interactions with ion transport, ion accumulation, and growth. The effects of salinity on Na and Ca transport to the shoot do not appear to play a major role in shoot growth of barley.

Notes: Abstract. Maintenance of realistically low solution P concentrations under controlled conditions is a major difficulty in studies of P nutrition. In this report, we describe a relatively simple and economical sand culture system capable of sustaining plant growth to maturity under controlled yet realistic P regimes. The system uses Al2O3 as a solid-phase P buffer, and modern process control technology to control irrigation and addition of other mineral nutrients. Aspects of the design, use and potential applications of automated solid-phase systems are discussed. The system was used to grow Phaseolus vulgaris to matarity at 0.4 mmol m3, 1.0 mmol m3 and 27 mmol m3 P with and without mycorrhizal inoculation. At flowering, low solution P concentrations were associated with reduced leaf concentrations of P in nonmycorrhizal plants, and reduced leaf concentrations of Ca in both mycorrhizal and nonmycorrhizal plants. Mycorrhizal inoculation increased leaf P, K, Mg and Mn concentrations, but reduced leaf N concentration. Low P regimes reduced final seed yield by diminishing both the number of pods per plant and the number of seeds per pod. Mycorrhizal inoculation significantly enhanced seed yield under low P regimes by increasing seed weight, the number of pods per plant, and the number of seeds per pod.

Notes: Abstract Seeds of Lyeopersicon esculentum cv. VF36 (a salt-sensitive cultivar), L. esculentum var. Edkawi (which is fairly salt-resistant), and a wild relative, L. cheesmanii, were exposed to various concentrations of NaCl, up to 460 mol m−3, either directly or following imbibition in non-saline nutrient solution. After 10 d exposure to salt, they were transferred to non-saline solution. All taxa showed some germination at the lowest salinity tested, 92 mol m−3 NaCl, but virtually no germination occurred at 184 mol m−3 NaCl or higher salinities. Within 2 d after removal of the salt stress, however, the seeds of L. esculentum reached control levels of germination, even if they had already been on the verge of germination when the stress was imposed. The seeds of L. cheesmanii were less resistant to NaCl. The physiological basis for the resistance of VF36 seeds is discussed.

Notes: We grew barley (Hordeum vulgare L. CM 72) for a 28-day period and sequentially harvested plants every 3 or 4 days. Plants were salt-stressed with either NaCl or KCl (125 mM) with or without supplemental Ca (10 or 0.4 mM final concentration, respectively). We determined tissue concentrations of Na, Ca, Mg, K. S, P, Fe, Mn, Cu and Zn for each harvest date by inductively coupled plasma spectrometry. Uptake (specific absorption rate) was calculated from the element content and growth rates. Salinity had significant effects on the uptake and concentrations of most elements. Mg and Mn concentrations declined with time. The concentrations of all other elements determined increased over time. Element uptake on a root dry weight basis declined with time. Three variables were significantly affected by salinity and correlated with growth; 1) the Ca concentration, 2) the total sum of the cation concentration (TC), and 3) the Mn concentration of the shoot. Salinity reduced Ca uptake and concentrations. Supplemental Ca increased Ca concentrations and was positively correlated with growth during salt stress. Salinity doubled TC, which was negatively correlated with relative growth rate (RGR). Relative growth rate declined at TC values above 150 mM. Salinity reduced the uptake and concentration of Mn. Manganese concentrations in the shoot were highly correlated with RGR. Relative growth rate declined at Mn concentrations below 50 nmol (g fresh weight)−1.

Notes: Indole-3-butyric acid (IBA) was recently identified by GC/MS analysis as an endogenous constituent of various plants. Plant tissues contained 9 ng g−1 fresh weight of free IBA and 37 ng g−1 fresh weight of total IBA, compared to 26 ng g−1 and 52 ng g−1 fresh weight of free and total indole-3-acetic acid (IAA), respectively. IBA level was found to increase during plant development, but never reached the level of IAA. It is generally assumed that the greater ability of IBA as compared with IAA to promote rooting is due to its relatively higher stability. Indeed, the concentrations of IAA and IBA in autoclaved medium were reduced by 40% and 20%, respectively, compared with filter sterilized controls. In liquid medium, IAA was more sensitive than IBA to non-biological degradation. However, in all plant tissues tested, both auxins were found to be metabolized rapidly and conjugated at the same rate with amino acids or sugar.Studies of auxin transport showed that IAA was transported faster than IBA. The velocities of some of the auxins tested were 7. 5 mm h−1 for IAA, 6. 7 mm h−1 for naphthaleneacetic acid (NAA) and only 3. 2 mm h−1 for IBA. Like IAA, IBA was transported predominantly in a basipetal direction (polar transport). After application of 3H-IBA to cuttings of various plants, most of the label remained in the bases of the cuttings. Easy-to-root cultivars were found to absorb more of the auxin and transport more of it to the leaves.It has been postulated that easy-to-root, as opposed to the difficult-to-root cultivars, have the ability to hydrolyze auxin conjugates at the appropriate time to release free auxin which may promote root initiation. This theory is supported by reports on increased levels of free auxin in the bases of cuttings prior to rooting. The auxin conjugate probably acts as a ‘slow-release’ hormone in the tissues. Easy-to-root cultivars were also able to convert IBA to IAA which accumulated in the cutting bases prior to rooting. IAA conjugates, but not IBA conjugates, were subject to oxidation, and thus deactivation. The efficiency of the two auxins in root induction therefore seems to depend on the stability of their conjugates. The higher rooting promotion of IBA was also ascribed to the fact that its level remained elevated longer than that of IAA, even though IBA was metabolized in the tissue.IAA was converted to IBA by seedlings of corn and Arabidopsis. The Km value for IBA formation was low (approximately 20 μM), indicating high affinity for the substrate. That means that small amounts of IAA (only a fraction of the total IAA in the plant tissues) can be converted to IBA. It was suggested that IBA is formed by the acetylation of IAA with acetyl-CoA in the carboxyl position via a biosynthetic pathway analogous to the primary steps of fatty acid biosynthesis, where acetyl moieties are transferred to an acceptor molecule. Incubation of the soluble enzyme fraction from Arabidopsis with 3H-IBA, IBA and UDP-glucose resulted in a product that was identified tentatively as IBA glucose (IBGIc). IBGIc was detected only during the first 30 min of incubation, showing that it might be converted rapidly to another conjugate.

Notes: Barley (Hordeum vulgare L. cv. CM 72) was grown for a 28-day period and stressed with treatments of 125 mol m−3 NaCl or KC1 with low Ca2+ (0.4 mol m−3 Ca2+) or high Ca2+ (10 mol m−3 Ca2+). Plants were harvested periodically so that relative growth rate (RGR), net assimilation rate (NAR) and leaf area ratio (LAR) could be calculated using the functional approach to plant growth analysis. Relative growth rate declined with time for all treatments, including controls. Salinity inhibited RGR relative to control values by day 10. High Ca2+ improved the growth of salt-stressed plants in both NaCl-salinity and KCl-salinity. KC1 proved more toxic than NaCl, especially for KCI-salinity plants with low Ca2+, which died by day 28. Net assimilation rate, but not LAR, was highly correlated with RGR for all treatments. This indicates that the photosynthetic-assimilatory machinery was limiting RGR and not the leaf area of the plant.

Notes: Indole-3-butyric acid (IBA) was much more effective than indole-3-acetic acid (IAA) in inducing adventitious root formation in mung bean (Vigna radiata L.) cuttings. Prolonging the duration of treatment with both auxins from 24 to 96 h significantly increased the number of roots formed. Labelled IAA and IBA applied to the basal cut surface of the cuttings were transported acropetally. With both auxins, most radioactivity was detected in the hypocotyl, where roots were formed, but relatively more IBA was found in the upper sections of the cuttings. The rate of metabolism of IAA and IBA in these cuttings was similar. Both auxins were metabolized very rapidly and 24 h after application only a small fraction of the radioactivity corresponded to the free auxins. Hydrolysis with 7 M NaOH indicates that conjugation is the major pathway of IAA and IBA metabolism in mung bean tissues. The major conjugate of IAA was identified tentatively as indole-3-acetylaspartic acid, whereas IBA formed at least two major conjugates. The data indicate that the higher root-promoting activity of IBA was not due to a different transport pattern and/or a different rate of conjugation. It is suggested that the IBA conjugates may be a better source of free auxin than those of IAA and this may explain the higher activity of IBA.