A general procedure for protoplast recovery,callus and plant regeneration in plants

A portion of this work was supported by NSF grant DCB 8718314 and by the Missouri Agricultural Experiment Station. This research is a joint contribution from the Missouri Agricultural Experiment Station, Journal Series No. 10,789 and from the Massachusetts Agricultural Experiment Station, Amherst, MA 01003; Journal Paper No. MAES 2959. Ousama Zaghmout was supported by the Food for the 21st Century Program, College of Agriculture, University of Missouri, Columbia, MO.     

Some physiological changes in Vinca rosea L. associated with mycoplasma-like disorders

The mycoplasma-like disorders associated with the aster yellowsand peach X-disease decreases the chorophyll and protein constituentsof Vinca rosea L. The reduction in total chlorophyll and proteinsare quantitative for both disorders but there is a preferentialreduction of chlorophyll a with respect to chlorophyll b inthe peach X-disease. ¹ Contribution from the Missouri Agricultural Experiment Station.Journal Series No. 7750, approved by the Director. (Received August 9, 1977; )     

Single locus heterosis

Summary Experimental evidence is reported in favor of superdominance in over-all vigor inArabidopsis thaliana in connection with two x-ray induced mutants. The tests adopted (outcrossing to unrelated tester, repeated recombination for 15 generations) failed to reveal any additional genetic variation. The genetic and physiolgical mechanism of superdominance is discussed in light of recent information on gene structure and function.Contribution from the Missouri Agricultural Experiment Station. Journal Series Number 2388. Approved by the Director.     

Post-harvest residue input to cropland

Summary Total annual input of carbon with crop residues to the soils in Missouri (North Central Region of the USA) was found to be about 3.7 t ha⁻¹ for wheat, 3.4 t ha⁻¹ for soybeans and 9.2 t ha⁻¹ for corn. Root biomass represented 40–50% of total residues and its accumulation appears to be influenced by climatic conditions. Estimates of carbon outflow from the ecosystem in the form of CO₂ were in good agreement with the biomass input. Contribution from the Missouri Agricultural Experiment Station Journal Series Number 9842. Funded in part by the USDA Grant SE 83-CRSR-2-230.     

Polysome formation in Pinus resinosa at initiation of seed germination

Ribonucleic acid systems present in dormant embryos of red pine(Pinus resinosa Ait.) were studied. Sucrose gradient centrifugationwas used to isolate ribosomes of dormant embryos and embryosimbibed for various times in the light. In dormant embryos,ribosomes existed as monomers. After imbibition, a gradual decreasein the monomers was observed, with subunits and polymers ofribosomes detected within 4 hr. When poly U was added to homogenatesof dormant embryos, formation of polysomes was observed aftera 15-min incubation at 25°C. However, artificial polysomeformation required some factors from heavy particles in thehomogenates. ¹ Contribution from the Missouri Agricultural Experiment Station,Journal Series No. 7079. ² Present address: Government Forest Experiment Station, Meguro,Tokyo, Japan. (Received April 20, 1971; )     

The allotetraploidization of maize

Summary Allotetraploidization is the creation of synthetic allotetraploids. The allotetraploidization of maize can be accomplished by concentrating DPA (differential pairing affinity) factors into stocks by a recurrent selection breeding system. Selection is based on pairing configuration frequencies and altered genetic ratios that reflect DPA. Both an observed decline in the quadrivalent frequency per meiocyte from 8.10 to 7.31 and genetic data disclosing a reduction in the average frequency of recessive waxy (wx wx) pollen from Wx Wx wx wx plants from 17.48% to 13.35%, indicate considerable progress has been made toward allotetraploidization. A simple model for the effect of DPA on chromosome pairing and genetic ratios is presented.Contribution from the Agricultural Research Service, U.S. Department of Agriculture, University of Missouri, Missouri Agricultural Experiment Station, Journal Series No. 9806     

Biogenic amine degradation by homogenates of the bulb mite,Rhizoglyphus echinopus (Fumouze and Robin) (Acari: Astigmata: Acaridae)

Whole homogenates of bulb mites rapidly metabolized 2-phenylethylamine (PEA) but were appreciably less active against tryptamine, 5-hydroxytryptamine, and dopamine; no degradation of octopamine was detected. The rate of PEA degradation by bulb mites was dependent upon both substrate and homogenate concentrations. PEA degradation was inhibited by pargyline (pI₅₀, 6.7), tranylcypromine (pI_{50 6.2}), and harmaline (pI_{50 4.1}), but not by 5-chloro-2,4-dimethoxyformanilide. These results suggested that PEA metabolism by bulb mite homogenates was catalyzed mainly by Type B monoamine oxidase.Contribution from the Missouri Agricultural Experiment Station, Columbia, MO. Journal Series No. 9777     

Soybean root respiration assessed from short-term14C-activity changes

During and immediately after labelling of soybeans (Glycine max. L.) in the field by exposure to¹⁴CO₂, its respiratory deposit into the soil atmosphere, and its liberation from the soil were used in conjunction with estimates of below-ground plant biomass to apportion total soil respiration. Root respiration of soybean plants at stage V₆ was estimated at 4 mg CO₂.(g root)^–1.h^–1. Soil biota, during the same time, contributed 35% of total soil respiration.Contribution from the Missouri Agricultural Experiment Station. Journal Series Number 10700. Funded in part by USDA Grant SE 83-CRSR-2-2309.     

Distributional gradients and variability of macroelement concentrations in the crowns of plantation grownPinus resinosa (AIT.)

Summary The vertical distribution of inorganic nutrient concentrations in red pine were dependent on the foliage age. Older foliage did not show an average vertical gradient while younger foliage did show a significant gradient. Horizontal gradients across foliage age classes in a branch whorl were consistent for all branch whorls, but the relative difference between the concentration of the current foliage and foliage three years-old or older was dependent on crown position. Coefficients of variation (CV) did not show a variability gradient in the crown for nitrogen and phosphorus. Variability of potassium tended to decrease as foliage age increased. Contribution of the University of Florida, Soil Science Department, Gainesville, FL and State University of New York, College of Environmental Science and Forestry, Syracuse, New York. Florida Agricultural Experiment Station Journal Series No. 3017.     

Changes in ribosomal patterns and a related membrane fraction during induction of cold hardiness in mimosa epicotyl tissues

Sucrose gradient profiles of polyribosomes from epicotyl tissuesof mimosa seedlings (Albizzia julibrissin Durazzini) were followedthroughout induction of cold hardiness. An unusual fractionappeared in the polyribosome region of sucrose gradients withadvancing stages of cold hardiness. Treatment of this unusualfraction and polyribosome fractions with RNase, Triton X-100and deoxycholate suggests that the unusual fraction consistedof chloroplast or mitochondrial membrane fragments. Free polyribosome patterns were retained throughout inductionof cold hardiness. However, the presence of polyribosomes duringadvancing stages of cold hardiness does not necessarily insureactive protein synthesis. ¹ This investigation was supported in part by National ScienceFoundation Grant GB 8692. ² Contribution from the Missouri Agricultural Experiment Station.Journal Series Number 6253. (Received November 30, 1971; )     

Changes in mimosa epicotyl soluble nucleic acid patterns: Comparisons between changes related to growth rate and changes related to degree of maturation

Soluble nucleic acids from Albizzia julibrissin epicotyl tissueswere extracted and fractionated at different times during lategermination. Seedlings were grown on two different growth regimes,one with a relatively constant growth rate and an increasingpercentage of mature tissues, and a second with an increasinggrowth rate but relatively constant percentage of mature tissues.Consistent changes were observed in distribution of specificsoluble nucleic acid fractions with growth rate and stage ofdevelopment. Stability of terminal groups of soluble nucleicacid also were related to growth and developmental patterns.Finally, degree of amino acid acceptance by total tRNA decreasedwith stage of development, but did not relate to growth ratesor percentage of mature tissues. ¹Contribution from the Missouri Agricultural Experiment Station.Journal Series No. 5586. (Received February 3, 1969; )     

Early flowering in Arabidopsis induced by DNA base analogs

Summary Various isogenic lines of Arabidopsis differing in a single factor controlling flower initiation were cultured aseptically on media containing bromodeoxycytidine and bromodeoxyuridine (10^-5 M). The wild type under short-day illumination (8 hours daily) and the late mutant gi ², in both continuous light and under short day, responded with dramatically earlier flower initiation. Another late mutant (ld) failed to respond. The effect of the DNA base analogs was nullified by the corresponding normal deoxyribonucleosides but not by the corresponding normal ribonucleosides.Contribution from the Missouri Agricultural Experiment Station. Journal Series No 4005. Approved by the Director.Supported by National Science Foundation Grant GB-1174.     

Testcross selection theory

Summary The purpose of this paper is to extend the theoretical basis for testcross selection theory from models assuming two alleles per locus to a model which is general for number and frequency of alleles. The expectations of genetic variances expressed among and within testcross families is presented for both inbred and population testers. Predicted change due to selection in testcross, non-inbred and selfed population performance with testcross selection are derived. Expected changes in testcross heterosis and inbreeding depression in the population are also derived. Approximate confidence intervals for predicted selection response are developed and appropriate sets of progeny to evaluate in order to estimate parameters of interest are identified.Contribution from the Missouri Agricultural Experiment Station. Journal Series No. 10063     

Acceleration of flowering of the long-day plant Arabidopsis by 8-azaadenine

Summary The incorporation of 8-azaadenine (2×10^-5M) to the aseptic culture medium reduced the time required for developing macroscopically visible flower primordia and the number of leaves appearing before the first flower buds to about half under 8 hrs daily illuumination in both wild type and a late monogenic mutant. In the presence of equimolar amount of adenine the flowering was not accelerated by the analog.Supported by National Science Foundation and U.S. Public Health Service grants.Contribution from the Missouri Agricultural Experiment Station. Journal Series Number 3008. Approved by the Director.     

Gene-dependent flavonoid glucosyltransferase in maize

A direct relationship between a specific gene and a specific enzyme involved in flavonoid biosynthesis is reported for the gene Bz and uridine diphosphoglucose: quercetin glucosyltransferase in maize pollen, seedlings, and seeds. Ratios are presented for specific activities of the glucosyltransferase from pollen, seed, and seedling tissues homozygous and heterozygous for Bz and homozygous for bz.Cooperative Investigations, Agricultural Research Service, United States Department of Agriculture and Missouri Agricultural Experiment Station, Columbia, Missouri 65201. Journal Series No. 7340.     

Biological transformations of phosphorus in soil

Summary Mathematical expressions were developed for calculating (1) the availability of soil phosphorus and nonradioactive inorganic fertilizer phosphorus to soil organisms, the measurements being expressed in terms of a standard source of inorganic phosphorus containing P³² added to the soil prior to incubation, and (2) the amounts of synthesized and mineralized organic phosphorus present in soils after incubation. Analytical procedures for obtaining the necessary data were described.Soil Phosphorus Research Project of the North Central Region. Contribution from the B.P.I.S.A.E., U.S. Department of Agriculture, and the Iowa Agricultural Experiment Station. Journal Paper No. J-2302 of the Iowa Agricultural Experiment Station, Ames, Iowa. Project No. 1183.Formerly Soil Scientist, U.S.D.A., and Collaborator, Iowa Agricultural Experiment Station; now Soil Scientist, Dow Chemical Co., Seal Beach, California. The author is indebted to Dr. L. A. Dean and Dr. C. A. Black for their many helpful suggestions in planning these investigations and preparing the data for publication.     

RFLP mapping of partially sequenced leaf cDNA clones in maize

We report here the results of mapping a set of 92 leaf cDNA clones in maize. The ends of each of these cDNA clones have previously been partially sequenced, and the sequence comparison has revealed the putative function for 28 clones. It is expected that the RFLP map developed using these expressed sequence tags will be of great importance for future maize genome analysis, such as for PCR-based gene mapping or gene function identification.Contribution from the Missouri Agricultural Experiment Station. Journal Series N. 12,019.     

Glucosyltransferase activity in a water extract of maize pollen

Summary Glucosyltransferase activity was extracted from maize pollen in distilled water. The enzymatic reaction required UDP-glucose, mercaptoethanol and Ca⁺⁺, and had a pH optimum at 8.2. Either kampferol or quercetin served as a substrate. Michaelis-Menten constants obtained were 0.6×10^-4 M for quercetin and 0.74×10^-3M for UDP-glucose. Ammonium-sulfate precipitation of the enzyme gave a 4fold purification.Cooperative investigations, Plant Science Research Division, Agricultural Research Service, U. S. Department of Agriculture, and Missouri Agricultural Experiment Station, Columbia. Journal Series No. 6224.     

Use of boreal forested wetlands by Pacific loons (Gavia pacifica Lawrence) and horned grebes (Podiceps auritus L.): relations with limnological characteristics

Our objective was to determine if the occurrence and abundance of Pacific loons (Gavia pacifica Lawrence) and horned grebes (Podiceps auritus L.) on 123 wetlands of Yukon Flats National Wildlife Refuge in east central Alaska were related to the limnological characteristics of those wetlands. Aquatic bird-wetland use surveys were conducted in conjunction with limnological sampling from May through September 1985–87 and May through August 1989. Results from logistic regression analysis demonstrated a significant association between the probability of wetland use by Pacific loons and shoreline length, water color, calcium and total phosphorus. Wetland use by horned grebes was related to shoreline length, pH, and chlorophyll. Aquatic bird abundance was then used as a Poisson response variable and modeled as a function of wetland limnological characteristics. Our results indicate that Pacific loon abundance was adequately modeled by linear and quadratic functions of shoreline length, color, pH, calcium and total phosphorus. Horned grebe abundance could not be modeled with this approach. The statistical techniques known collectively as generalized linear models provided a framework for the development of models for aquatic bird use of wetlands. Our results, however, indicate that while this approach shows promise, a better understanding of how to model aquatic bird abundance is needed. We then identify problems in model development and suggest avenues for future research.Contribution of the Missouri Agricultural Experiment Station Journal Series No. 11604.     

Germination and production ofMacrophomina phaseolina microsclerotia as affected by oxygen and carbon dioxide concentration

Summary Germination of microsclerotia ofMacrophomina phaseolina was observed at O₂ concentrations of 16% or higher in autoclaved soil. Germination was delayed but otherwise unaffected as O₂ decreased from 21 to 16% and was in all cases complete in 32 hours. Laboratory-produced microsclerotia consistently germinated more rapidly and seemed more independent of O₂ concentrations within the range that permitted germination than naturallyproduced microsclerotia.Population changes in soil as measured by microsclerotial counts were inversely correlated with depth of interment and reduced O₂ concentration. Our inability to detect significantly growth responses ofM. phaseolina in non autoclaved soil was apparently related to limited O₂ although other possibilities are discussed.Contribution of the Missouri Agricultural Experiment Station Scientific Journal Series No. 9124.