The diversity and abundance of small arthropods in onion, Allium cepa, seed crops, and their potential role in pollination.

Onion, Allium cepa L. (Asparagales: Amaryllidaceae), crop fields grown for seed production require arthropod pollination for adequate seed yield. Although many arthropod species visit A. cepa flowers, for most there is little information on their role as pollinators. Small flower visiting arthropods (body width < 3 mm) in particular are rarely assessed. A survey of eight flowering commercial A. cepa seed fields in the North and South Islands of New Zealand using window traps revealed that small arthropods were highly abundant among all except one field. Insects belonging to the orders Diptera and Thysanoptera were the most abundant and Hymenoptera, Collembola, Psocoptera, Hemiptera, and Coleoptera were also present. To test whether small arthropods might contribute to pollination, seed sets from umbels caged within 3 mm diameter mesh cages were compared with similarly caged, hand-pollinated umbels and uncaged umbels. Caged umbels that were not hand-pollinated set significantly fewer seeds (average eight seeds/umbel, n = 10) than caged hand-pollinated umbels (average 146 seeds/umbel) and uncaged umbels (average 481 seeds/umbel). Moreover, sticky traps placed on umbels within cages captured similar numbers of small arthropods as sticky traps placed on uncaged umbels, suggesting cages did not inhibit the movement of small arthropods to umbels. Therefore, despite the high abundance of small arthropods within fields, evidence to support their role as significant pollinators of commercial A. cepa seed crops was not found.

A novel alliinase from onion roots. Biochemical characterization and cDNA cloning.

We have purified a novel alliinase (EC 4.4.1.4) from roots of onion (Allium cepa L.). Two isoforms with alliinase activity (I and II) were separated by concanavalin A-Sepharose and had molecular masses of 52.7 (I) and 50.5 (II) kD on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and 51 (I) and 57.5 (II) kD by gel filtration fast-protein liquid chromatography. Isoform I had an isoelectric point of 9.3, while isoform II had isoelectric points of 7.6, 7.9, 8.1, and 8.3. The isoforms differed in their glycosylation. Both contained xylose/fucose containing complex-type N-linked glycans, and isoform II also contained terminal mannose structures. Both isoforms had activity with S-alk(en)yl-L-cysteine sulfoxides. Unlike other allium alliinases, A. cepa root isoforms had cystine lyase activity. We cloned a gene from A. cepa root cDNA and show that it codes for A. cepa root alliinase protein. Homology to other reported allium alliinase genes is 50%. The gene coded for a protein of mass 51.2 kD, with two regions of deduced amino acid sequence identical to a 25- and a 40-amino acid region, as determined experimentally. The A. cepa root alliinase cDNA was expressed mainly in A. cepa roots. The structure and function of the alliinase gene family is discussed.

Linkage mapping of quantitative trait loci controlling seed weight in pea (Pisum sativum L.).

Quantitative trait loci (QTLs) affecting seed weight in pea (Pisum sativum L.) were mapped using two populations, a field-grown F2 progeny of a cross between two cultivated types ('Primo' and 'OSU442-15') and glasshouse-grown single-seed-descent recombinant inbred lines (RILs) from a wide cross between a P. sativum ssp. sativum line ('Slow') and a P. sativum ssp. humile accession ('JI1794'). Linkage maps for these crosses consisted of 199 and 235 markers, respectively. QTLs for seed weight in the 'Primo' x 'OSU442-15' cross were identified by interval mapping, bulked segregant analysis, and selective genotyping. Four QTLs were identified in this cross, demonstrating linkage to four intervals on three linkage groups. QTLs for seed weight in the 'JI1794' x 'Slow' cross were identified by single-marker analyses. Linkage were demonstrated to four intervals on three linkage groups plus three unlinked loci. In the two crosses, only one common genomic region was identified as containing seed-weight QTLs. Seed-weight QTLs mapped to the same region of linkage group III in both crosses. Conserved linkage relationships were demonstrated for pea, mungbean (Vigna radiata L.), and cowpea (V. unguiculata L.) genomic regions containing seed-weight QTLs by mapping RFLP loci from the Vigna maps in the 'Primo' x 'OSU442-15' and 'JI1794' x 'Slow' crosses.

Spectrophotometric assay and electrophoretic detection of trans-feruloyl esterase activity.

Wheat bran cell walls were subjected to mild acid hydrolysis and the major phenolic product was purified and identified as 5-O-(trans-feruloyl)-arabinofuranose. Sensitive continuous and stopped, microtiter plate-based spectrophotometric assays for trans-feruloyl esterase activity were developed using this compound as substrate. Procedures were also developed for the detection of trans-feruloyl esterase activities on gels following electrophoresis using this compound. These procedures are applicable to other natural feruloyl esters derived from plant cell walls by enzymatic hydrolysis. The extracellular trans-feruloyl esterases of Aspergillus niger 814 grown on 1% wheat bran were fractionated by anion-exchange chromatography and isoelectric focusing. These studies indicate that there are multiple forms of trans-feruloyl esterase but that most activity is associated with a major isozyme with a pI of 3.2.

Medical services at a music festival.

A three-day open air musical festival attended by approximately 20 000 people was held at Ngaruawahia in January 1973. A medical service was provided and staffed mainly by medical students, nurses and young medical graduates. There were 1998 patient visits to the medical area, the five most common complaints being sunburn, headaches, minor foot trauma, gastroenteritis and lacerations which collectively accounted for 75 percent of the diagnoses. The medical services provided are discussed and recommendations for future festivals made.