Gary D. Jolliff

Papaver bracteatum, potential commercial source of codeine

Papaver bracteatum, native to Iran and southern Russia, has been grown successfully in many countries. Research in the northwest United States has confirmed the potential for its commercial production as a source of the alkaloid thebaine. Potential for the chemical conversion of thebaine into codeine, one of man’s most widely used alkaloidal medicinal agents, is reviewed. Economic and social advantages of growing this species over opium poppy (Papaver somniferum) are discussed. The value of the seed oil for cooking and industrial use is considered.

Seed germination and dormancy of new meadowfoam (Limnanthes spp.) genotypes

Abstract Reliable information on the germination characteristics of Meadowfoam (Limnanthes spp.), a new oilseed crop, will greatly aid in its full commercialization. Soil temperatures above 15–17°C may be common at planting time in western Oregon, and can severely limit seed germination of the cultivar Mermaid. Information on seed germination and dormancy of the new cultivar Floral and more recently developed genetic lines is not available. Effects of three temperature regimes (constant 9°C; and alternating 15 3 and 18 6 °C on 8 16 h cycles), two levels of KNO3 (0 and 1 g l−1) and two seed pre-conditioning treatments (chilling for 48 h at 1°C, and no chilling) on germination were tested for the older cultivar Mermaid, the new cultivar Floral, and some newer lines developed through selection for high oil yield. Seedling emergence of all entries was also measured in the field. Seed germination varied among genotypes under all temperature treatments; genotype by temperature regime interaction was not significant. Pre-chilling enhanced the initial germination rate of all genotypes, but had little effect on the final number of seeds germinated. The effects of KNO3 on seed germination varied among genotypes and among temperature regimes, suggesting genetic variation for seed dormancy. Results also indicate that primary and secondary seed dormancy have been reduced in Floral and in several of the new lines. Field emergence most closely correlated with germination under the 15 3 °C regime with zero KNO3 and no pre-chilling. Selection from existing elite breeding lines for further reductions in dormancy (primary as well as secondary) and improvements of germination seems readily feasible and should contribute to meadowfoam commercialization.

Nitrogen rate and timing effects on meadowfoam oil yield and oil-yield components

Abstract Unlike earlier meadowfoam ( Limnanthes alba Hartw. ex Benth.) accessions and genetic lines, seed yield of the more recently released cultivar ‘Mermaid’ is increased with low to moderate rates of N-fertilizer. Understanding N-fertilizer effects on oil yield and yield components is useful for improving fertilizer management which is important economically and environmentally. The objective of this experiment was to evaluate effects of 12 combinations of N rate and timing treatments (50, 100 and 200 kg N ha −1 × fall, winter, spring and split fall/spring applications) plus a control (0 kg N ha −1 ) on Mermaid oil yield and oil-yield components. Experiments were conducted in 1982–1983 and 1984–1985 on a Woodburn silt loam (fine-silty, mixed, mesic Aquultic Argixerolls) near Corvallis, OR, USA. Except for the 50 and 100 kg N ha −1 applied in the fall of 1984, all N rates significantly increased oil yield over the control. Combined over years, there was a quadratic relation between N rates and oil yield. Application timings did not interact with rates for their effects on oil yield, or on any of the oil-yield components. Fall N application resulted in smaller oil-yield increase than the other timing treatments. Total flower number was the only oil-yield component significantly affected by treatments in both years. Averaged over years, flower number increased by 38, 72 and 92% when 50, 100 and 200 kg N ha −1 were applied, respectively. However, the relationship between N rates and flower production was also quadratic. Slight reductions in seeds per flower and weight per seed caused by N applications were more than offset by increased flower number. Effects of N application on seed oil content contributed little to oil-yield differences. Regardless of timing or rate, the primary effect of N fertilizer on oil yield was through increased flower number, and consequently, increased seed number.

Soil fertilization and pH effects on meadowfoam growth and flowering 1

Abstract Meadowfoam (Limnanthes alba Hartweg ex. Bentham) is a new oilseed crop. Published information on nutritional requirements and optimum soil pH for growing meadowfoam in controlled environments is currently lacking. This study evaluated the effects of application rates and timing of a modified Hoaglands solution and a range in initial potting medium pH on meadowfoam (L. alba subsp. alba, cv Mermaid) growth and development under controlled environment conditions. Weekly application of 50 mL of nutrient solution at a nitrogen (N) concentration of 840 mg/L (four times higher than the concentration in modified Hoaglands solution) resulted in good Mermaid growth and flower production. Optimum fertilizer application timing is apparently from one week after transplanting (38 days after seeding) until the flowering stems begin to elongate above the rosette leaves. Optimum soil pH seemed to be between 5 and 6, although Mermaid grew relatively well under initial soil pH ranging from 3.8 to 7.3.

Photosynthesis of meadowfoam leaves at various photon fluxes and CO2 concentrations

Abstract Meadowfoam (Limnanthes alba Hartweg ex Benth.) is a new oilseed crop. Information regarding the effects of photosynthetic photon flux (PPF) and carbon dioxide concentration [CO2] on net photosynthesis is important for understanding the potential capacity and the limitations of this crop to assimilate CO2. Such information is useful for further improvement of meadowfoam seed and oil yield, as well as for growing this plant in controlled environments. The steady-state CO2 exchange rates (CER; leaf area basis) of Mermaid meadowfoam (L. alba subsp. alba) leaves were measured in a semi-closed compensating system at various PPF and [CO2]. Measurements were made on rosette leaves of controlled environment-grown plants during vegetative growth, early stem elongation and early flowering. At all stages of development, CER responded hyperbolically to PPF and reached near saturation at a PPF of about 900 μmol m−2 s−1 when [CO2] was 340 μl l−1. At saturating PPF, leaf CER was 18 μmol m−2 s−1 during the vegetative stage, 15 μmol m−2 s−1 at early stem elongation and 8 μmol m−2 s−1 at early flowering. The apparent quantum yield (mole CER per mole PPF at leaf surface) determined at low PPF when the response curve was linear was the same during vegetative and early stem elongation. The 99% confidence intervals for the apparent quantum yield of these plants were 0.038 and 0.046. The 99% confidence intervals for light compensation point during these stages were 63 and 79 μmol m−2 s−1. During both vegetative and early stem elongation stages, the CER increased sharply as [CO2] increased (PPF=1200 μmol m−2 s−1) and reached a plateau near 650 μl l−1 CO2. At this saturating [CO2], the CER was 45 μmol m−2 s−1 during the vegetative stage and 33 μmol m−2 s−1 during early stem elongation. The [CO2] compensation point measured transiently on four plants during vegetative stage was 74±5 μl l−1. The photosynthetic rate and efficiency of L. alba were similar to those for cool-season C3 grasses.