Studies on the cultivation and uses of evening primrose (Oenothera spp.) in China

Evening primrose originated in North America and became naturalized in the north-east of China about one hundred years ago, where it has been used as famine food and animal feed. New uses for the seed oil, which contains γ-linolenic acid (GLA), that have been developed in China and overseas since 1980 have created a much larger commercial demand for the seed. There are eight species of Oenothera L. growing wild in China, of which Oenothera biennis L. is preferred. The maximum annual production of wild evening primrose seed is estimated to be about 3000 tons but, since 1986, evening primrose has also been cultivated for its seed and oil using O. biennis (primarily in the provinces of Jilin, Liaoning, Hebei, and Shandong) to meet the increasing demand. New production techniques have been developed and disseminated, and reported seed yields range from 750 to 3000 kg ha^-1. Commercial production follows a cyclical pattern, with the largest harvest to date, in 1999, estimated at 16 000-19 000 tons of seed. During 20 years of research on a wide range of wild oilseed plants, Chinese scientists found that evening primrose oil was antiatherosclerotic, lowered hyperlipidemia and was antithrombotic. The oil was developed and licensed as a drug (which required work on processing technology, physicochemical characteristics, pharmacology, formulation, and clinical studies) and it has since been widely used in clinical practice. Further research work has been done on other bioactive properties of evening primrose oil, alternative sources of GLA, the concentration of GLA, the synthesis of prostaglandin E1, and the development of health care drugs and cosmetics containing evening primrose oil. We believe that the prospects for the future development of evening primrose are good.     

The safety of evening primrose oil in epilepsy

The concern that evening primrose oil might cause epilepsy or seizures, or reduce the threshold for seizures, originated from two papers published in the early 1980s. These original reports are re-examined, and the association of evening primrose oil with seizures is shown to be spurious. Not only are linoleic acid and gamma-linolenic acid safe in epilepsy, with prolonged oral administration of linoleic acid and alpha-linolenic acid (in a 4:1 mixture) protecting rats from having seizures in four different epilepsy models, but the evening primrose oil-derived omega-6 fatty acid arachidonic acid inhibits sodium ion currents and synaptic transmission, while the evening primrose oil-derived eicosanoid prostaglandin E(1) appears to have anticonvulsant activity. In light of these findings, it is suggested that formularies should now remove seizures or epilepsy as a side-effect of evening primrose oil, and should remove a history of seizures or epilepsy as a contraindication to taking evening primrose oil.     

High frequency of adventitious shoot regeneration from commercial cultivars of evening primrose (Oenothera spp.) using thidiazuron

Evening primrose (Oenothera spp.) is grown commercially for its seed oil that contains gamma linolenic acid (GLA), a valuable food supplement and pharmaceutical. There is considerable interest in the potential of genetic engineering to improve yields of GLA in evening primrose, and attention has focused on the current state of tissue‐culture knowledge in this species which is a prerequisite for genetic transformation. Published protocols for the regeneration of plants from leaf or cotyledon material of Oenothera spp. are available, but these prove unsatisfactory when applied to commercial cultivars used in this study. An efficient method for regenerating three commercial cultivars of evening primrose Rigel, Merlin and Vulcan was developed using thidiazuron (TDZ) as a growth regulator. Explants from one month old seedlings were cultivated in vitro; a large number of buds were induced directly from strips of leaves, cotyledons and stems when cultured on Murashige and Skoog (MS) basal medium containing TDZ and indole‐butyric acid (IBA). Shoots that were excised and placed onto MS basal medium, supplemented with IBA, rooted with 85–90% efficiency. Plantlets were transferred to soil after 6–8 wk. TDZ stimulated the regeneration process, and its effects were enhanced when combined with IBA or indole‐3‐acetic acid (IAA). The methods developed may be a useful advance toward improvement of this oil seed crop through genetic modification.     

Enzymatic fractionation of evening primrose oil by rape lipase: Enrichment of gamma-linolenic acid

Summary Rape lipase discriminates strongly against -linolenic acid (allcis-6, 9, 12–183; GLA). GLA in the fatty acids from evening primrose oil was concentrated from 9.5% to 62% with a 95% yield during esterification of these fatty acids with butanol catalyzed by rape lipase. Hydrolysis of evening primrose oil catalyzed by the rape lipase raised the GLA content in unhydrolyzed acylglycerols to 28%.     

THE EIGHTY-YEAR PERIOD FOR DR. BEAL'S SEED VIABILITY EXPERIMENT

Darlington , H. T., and G. P. Steinbauer . (Michigan State U., East Lansing.) The eighty-year period for Dr. Beal's seed viability experiment. Amer. Jour. Bot. 48 (4): 321–325. 1961.—Seeds of 20 species of plants were buried 80 years ago on the Michigan State University campus. Bottles have been dug up periodically in the intervening years and the seeds tested for viability. A bottle representing the 80-year period of burial was dug up this spring and the contents distributed uniformly on the surface of sterilized soil in the greenhouse. Of the 20 species whose seeds were buried in 1879, only 3 have survivors as viable seeds. These are the same 3 that had survived the 70-year burial period, namely: curled dock, Rumex crispus; evening primrose, Oenothera biennis; and moth mullein, Verbascum blattaria. The low percentage survival of curled dock (2%) indicates that the longevity of the buried seeds of this species is nearing the end. The situation is more favorable for evening primrose, with 10% survival. The third, moth mullein, has about as many survivors as 10 years ago, a remarkably high figure of 70% viability. Since there has been no significant drop in viability of the buried seeds over the last 30 years, it seems highly probable that longevity of buried seeds of this species may extend over a century. A brief summary is given of the current status of the behavior of buried seeds, based on this and other buried seed experiments.     

DEVELOPMENT OF POWDERY MILDEW (ERYSIPHE POLYGONI) ON SUSCEPTIBLE AND RESISTANT RACES OF OENOTHERA BIENNIS

Races of Oenothera biennis (evening primrose) resistant and susceptible to Erysiphe polygoni (a powdery mildew fungus) were artificially inoculated with E. polygoni and the time course and mode of disease development recorded. This study was the initial stage in investigating the host's resistance mechanism(s). On leaves of susceptible and resistant races, spores germinated within 5 hr, appressoria were formed in 8-12 hr, and penetration had been effected and haustoria initiated by 20 hr. There was no further development on resistant plants. On susceptible hosts, secondary penetration occurred by 26 hr after inoculation, secondary haustoria were formed, and sporulating colonies were seen in 4 days. It was concluded that the fungus is unable to establish a feeding relationship with the epidermal cells of resistant Oe. biennis, marking the period between 20 and 26 hr after inoculation as the time frame for the manifestation of the resistance mechanism(s).     

Attempts at dietary alteration of prostaglandin pathways in the management of pre-eclampsia

It has been suggested that dietary supplementation with prostaglandin precursors may enhance the synthesis of PGE which lowers vascular sensitivity to increased levels of angiotensin II in pregnancy. Therefore the effect of dietary supplementation with evening primrose oil (linoleic acid and gamma-linoleic acid) in African primigravidae with established pre-eclampsia was studied. Patients were randomly allocated to one of two groups. Group A (23 patients) received 8 capsules/day of evening primrose oil and group B (24 patients) received 8 capsules of placebo. No significant differences were found between the groups in respect to perinatal outcome, blood pressure lowering effect and haematological indices.     

Phenological stages of willow (Salix)

The practice of uniform recording of biological plant growth stages or events has long been practiced in agricultural production. In this study the BBCH (Biologishe Bundesanstalt, Bundessortenamt and CHemical Industry) code has been applied to four precocious species of willows to define growth stages important to this group. The studied taxa represent varieties of potential importance in the Floral Industry. A new BBCH code is proposed where the annual cycle of willows is divided into clearly recognisable and easily distinguishable developmental phases which include eight principal stages, 30 secondary stages and six mesostages. Photographs illustrate the physical appearance of select stages. This proposed BBCH code shows a unified approach which may be applied to a large number of Salix species.     

Complete nucleotide sequence of the Oenothera elata plastid chromosome, representing plastome I of the five distinguishable euoenothera plastomes

We describe the 159,4443-bp sequence of the plastid chromosome of Oenothera elata (evening primrose). The Oe. elata plastid chromosome represents type I of the five genetically distinguishable basic plastomes found in the subsection Euoenothera. The genus Oenothera provides an ideal system in which to address fundamental questions regarding the functional integration of the compartmentalised genetic system characteristic of the eukaryotic cell. Its highly developed taxonomy and genetics, together with a favourable combination of features in its genetic structure (interspecific fertility, stable heterozygous progeny, biparental transmission of organelles, and the phenomenon of complex heterozygosity), allow facile exchanges of nuclei, plastids and mitochondria, as well as individual chromosome pairs, between species. The resulting hybrids or cybrids are usually viable and fertile, but can display various forms of developmental disturbance. Received: 9 January 2000 / Accepted: 29 January 2000     

Effect of Temperature on the Fatty Acid Composition and Yield of Evening Primrose (Oenothera lamarckiana) Seeds

The oil content and yield of evening primrose (Oenothera lamarckianaL.) seeds decreased significantly at high temperatures (32 ?C)compared with lower ones (25 ?C and below), under controlledgrowing conditions. Moreover, the fatty acid composition ofthe seed oils was also affected by the temperature regime. Higheroleic acid levels and lower linoleic and -linolenic acid (GLA)levels were characteristic of the seeds developed at highertemperatures. The opposite trend was observed at lower temperatures.In field experiments, seeds of O. lamarckiana plants sown inautumn contained lower oleic acid levels, and higher linoleicacid and GLA levels than seeds of spring plantings. This effectwas also demonstrated for seeds developed on the same stem inflorescenceunder increasing temperatures during the season in the field.Changes in fatty acid composition during various stages of seeddevelopment were observed. Key words: Evening primrose, oil, fatty acids, Oenothera spp., gamma linolenic acid     

Evaluation of the anti-<Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp <Emphasis Type="Italic">cicer</Emphasis> and anti-<Emphasis Type="Italic">Alternaria porri</Emphasis> effects of some essential oils

The anti-Fusarium oxysporum f. sp cicer (FOC) and anti-Alternaria porri (A. porri) effects were evaluated for 75 different essential oils. The most active essential oils found were those of lemongrass, clove, cinnamon bark, cinnamon leaf, cassia, fennel, basil and evening primrose. However, the effectiveness of these essential oils with both the tested fungi showed different responses. The level of inhibition was compared with Hexaconazole. GC–MS analysis for five oils amongst the 75 essential oils tested was performed. The potential of these essential oils as an ecofriendly and economic approach as a fungicide for FOC and A. porri is discussed.