meiotic process in plants or animals does not necessarily produce the same T:!rcentage of recombinants in male and female germ cells. In maize, the frequency of recombination in a particular chromosomal region is usually higher in microsporogenesis than in megasporogenesis, if a difference exists at all. Chromosomes 2 and 10, according to genetic tests thus far, have similar recombination frequ...

The nucleotide sequence has been determined for a 664-base pair region of maize (Zea mays L.) mtDNA which contains the 3' end of the 18S rRNA gene, the 5S rRNA gene, and an intergenic region of 108 base pairs. Specific regions of the 18S rRNA gene show striking homology with the corresponding gene in Escherichia coli.

Evidence is presented that intracellular ammonium is trapped in vacuoles of maize (Zea mays L.) root tips because of rapid movement of ammonia between cytoplasm and vacuoles. The concentration of cytoplasmic ammonium is estimated to be <15 mum at extracellular ammonium concentrations up to 1 mm. The implications for pathways of ammonium assimilation are discussed.

Spiroplasma kunkelii causes corn stunt disease of Zea mays L. in the Americas. Here, we report the nucleotide sequence of the 1,463,926-bp circular chromosome and four plasmids of strain CR2-3x. This information will facilitate studies of Spiroplasma pathogenicity and evolutionary adaptations to transkingdom parasitism in plants and insect vectors.

Eddy covariance and static chambers are different-scale methods for monitoring agricultural N2O that, when used together on heterogeneous agricultural landscapes, can help identify flux sources and sinks and evaluate the effect of management interventions on landscape-scale N2O emissions. This study compared the N2O flux data obtained by eddy covariance and static chambers during a short-term N...

The first and second leaf sheaths of Zea mays L. cv Golden Jubilee were extracted and the extract centrifuged at 100,000g to yield a supernatant or cytosol fraction. Binding of [(3)H]gibberellin A(1) (GA(1)) to a soluble macromolecular component present in the cytosol was demonstrated at 4 degrees C by Sephadex G-200 chromatography. The binding component was of high molecular weight (HMW) and g...