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.     

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; )     

Limnological reconnaissance of waterbodies in central and southern Nepal

Ionic composition of waterbodies in central and southern Nepal sampled in spring 1985 differed from that normally found in freshwater. Distinguishing characteristics were: 1) predominance of bicarbonate among the anions — accounting for > 90% of the negative equivalents in two-thirds of the waterbodies, 2) the near absence of sulfates — accounting for < 1 % of the anions in half the samples so that chloride exceeded sulfate (as meq/L) in three-fourths of the waters tested and 3) calcium was the dominant cation, although in certain waters the relative proportion of either magnesium or the monovalent cations was much higher than the world average. Regional patterns in water chemistry were apparent and are largely explained by differences in local geology, inputs from artesian wells or extensive use by humans. Most ionic salinity values were <400 mg/L. Using conventional criteria to assess trophic state, most water-bodies were eutrophic or hypereutrophic when judged by total phosphorus and chlorophyll content but as a whole the lakes sampled were low in nitrogen. Nitrogen: phosphorus ratios (generally < 10) and a significant empirical relation for chlorophyll-nitrogen provide evidence that nitrogen limited algal biomass. Secchi transparency values indicate light regimes were affected by nonalgal materials. Contribution of the Missouri Agricultural Experiment Station Journal Series No. 10503. Contribution of the Missouri Agricultural Experiment Station Journal Series No. 10503.     

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     

A phylogenetic comparison of mutation spectra

Summary Spectra of induced mutations resulting in obligate organoauxotrophy are compared at different phylogenetic levels from bacteria to higher plants. It appears that the spectra of mutants concerned with basic cell metabolism are more or less the same in bacteria and fungi. In higher, green plants (an alga and an angiosperm) the spectra are qualitatively different. Mutation frequency in certain pathways is common, while in others no mutants have been found. This lack of recovery of many classes of mutants indicates a reduction, by several orders of magnitude, in either mutability or detectability of the mutants in the majority of the biosynthetic systems.Contribution from the Missouri Agricultural Experiment Station. Journal Series No. 5167. Approved by the Director.This work was supported by National Science Foundation Grants GB-3999, GB-4301 and U.S. Atomic Energy Commission Contract AT (11-1)-1609.     

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.     

Effect of soybean plant growth on spore production byGlomus mosseae

Plants of two soybean cultivars infected withGlomus mosseae were physiologically stressed by top removal and were harvested at seven bi-weekly intervals. Removing tops stopped root growth, stimulated branching, delayed plant growth stages by approximately two weeks, but did not affect spore production. Spore numbers were significantly related only to time of harvest. Pot variation in spore number was not significantly correlated with infection percentage or root dry weight. Harvest, cultivar, and cutting effects were highly significant for root and shoot weights and root/shoot ratios.Approved by the Director as a contribution from the Missouri Agricultural Experiment Station (Journal Series No. 8123).     

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; )     

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     

Thiamine mutants of the crucifer,Arabidopsis

In higher plants the only obligate organoauxotrophic mutants available are concerned with the synthesis of thiamine, vitamin B₁. In Arabidopsis 65 mutants, representing four loci controlling four different steps in the thiamine pathway, have been obtained and identified. Heteroalleles were distinguished within two loci by qualitative and quantitative responses to low and high temperatures. The availability of auxotrophs in higher plants makes it possible to employ highly selective genetic techniques in well-differentiated diploid organisms.This work was supported by National Science Foundation Grant GB 6577 and U.S. Atomic Energy Commission Contract AT-(11-1)-1609. This is a contribution from the Missouri Agricultural Experiment Station. Journal Series Number 5477. Approved by the Director.     

Associative nitrogenase activity by some Hawaiian grass roots

Summary Nitrogenase activity by the roots of some tropical grasses was detected by the acetylene reduction technique. In some cases particular plant species, evaluated at different times from different sites, displayed marked variations in nitrogenase activity.Acetylene reduction by root samples which had undergone preincubation under low O₂ displayed an increase of approximately 5-fold when compared to plant-containing soil cores. These increases in nitrogenase activity correspond to an increase in the number of nitrogen-fixing bacteria associated with the roots.Journal Series No. 2066 of the Hawaii Agricultural Experiment Station, Honolulu, Hawaii 96822Journal Series No. 2066 of the Hawaii Agricultural Experiment Station, Honolulu, Hawaii 96822     

Sampling variance of the correlation coefficients estimated from analyses of variance and covariance

Summary A generalized sampling variance of correlation coefficients is derived for phenotypic, genetic and en vironmental correlations estimated from nested analyses of variance and covarianee for the equal number case. A numerical example is presented to estimate the sampling variance for the genetic correlation coefficient based on the relationship among full sibs using unequal subclass numbers.Journal Paper No. 3472 of the Purdue University Agricultural Experiment Station. This research was supported, in part, by NIH Biometry Training Grant, GM-00024.     

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.     

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; )     

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     

The allotetraploidization of maize

Summary Allotetraploidization is the creation of artifical allotetraploids from a normally diploid species. The possible value of allotetraploid maize has been discussed in Section I of this series. Allotetraploidization of maize can be achieved by restructuring a maize genome so that its chromosomes will not pair with those of the standard maize genome. This restructuring can be done by concentrating differential pairing affinity (DPA) factors into a single line by a recurrent selection type of breeding program. Because the divergence of the maize genome is a gradual process, it is necessary to devise a model for chromosome pairing and gene segregation in segmental allotetraploids. This has been done by considering pairing in each arm separately and then combining paired arms to form pairing configurations for whole chromosomes. The chromosome disjunction patterns are hypothesized and genetic ratios in relation to different levels of DPA are suggested.Contribution from the Science and Education Administration, U.S. Department of Agriculture, and the Agronomy Department, University of Missouri, Columbia, Missouri, Agricultural Experiment Station Journal Series No. 8090     

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.     

The dissociation of insect embryos for cell culture

Summary Procedures and solutions were developed for dissociating embryos ofBlattella germanica in preparation for primary cell culture. Trypsin solutions were maximally effective at 0.01% for germ bands but higher concentrations, 0.05 to 0.1% were needed for embryos in later stages. This investigation was supported by U.S. Public Health Service Research Grant No. AI 09914 from the National Institute of Allergy and Infectious Diseases. This is paper No. 8855, Scientific Journal Series, Minnesota Agricultural Experiment Station. The work was selected from the dissertation of T. J. K. presented for the Ph. D. degree at the University of Minnesota.     

Desiccated quiescent somatic embryos of orchardgrass for use assynthetic seeds

Summary Somatic embryos of orchardgrass became quiesent when desiccated to 13% water. Twelve percent germinated after 21 d of desiccated storage at 23° C and 4% developed into green plants. During desiccation, embryos decreased in size, became yellowish and brittle, and their outer walls collapsed. Within 15 min after imbibition, they rapidly enlarged and were indistinguishalbe from nondesiccated embryos. These results suggest that somatic embryos may be engineered to function as synthetic seeds for mass propagation. This research represents a collaborative effort between the Agricultural Experiment Stations of the University of Florida and the University of Tennessee. Research was supported in part by the Competitive Research Grants Office of the U.S. Department of Agriculture, grant 82-CRCR-1-1086, awarded to the University of Tennessee. Florida Agricultural Experiment Station Journal Series No. 7173.