Bituminaria bituminosa C.H. Stirton

Synonyms: Psoralea bituminosa L.

Authors: Daniel Real^1,2,3; Correal, E.⁴; Méndez. P.⁵; Santos, A.⁵; Ríos, S.⁶; Sternberg, M.⁷; Dini-Papanastasi, O.⁸ Pecetti, L.⁹ and Tava, A.⁹

Origin and geographical distribution

Bituminaria bituminosa (L.) C.H. Stirton is widely distributed in the Mediterranean Basin and Macaronesia. A large diversity exists in the Canary Islands with 3 botanical varieties described and other ecotypes under study. They are found in habitats ranging from the coastal semiarid areas on Lanzarote Island with an annual rainfall of 150mm to 300mm (var. albomarginata) to the high elevation subhumid area of Tenerife with up to 500 mm annual rainfall (var. crassiuscula). The third var. bituminosa has a wider adaptation across the Canary Islands with significant differences among biotypes (Méndez et al. 2006) and is also widely distributed in the Mediterranean basin (Méndez and Fernández 1990; Méndez et al. 1991). The fourth var. hulensis is present in the Hula Valley area, Israel, where it grows alongside water courses or springs (Zohary 1972).

Description

Herbaceous perennial; leaves cauline or acauline, pinnately or subdigitately 3-foliolate, linear-lanceolate to broadly-ovate with entire margins, or broadly ovate to orbicular with irregularly denticulate margins gland-dotted, shortly or stiffly pubescent; stipules linear-subulate, persistent; flowers sessile or subsessile, aggregated in 5-16 triplets into long pedunculate axillary capitate-umbellate or compact racemose inflorescences, each triplet subtended by a single variously 3(-5)-cleft bract, becoming smaller, narrower higher up or wanting at the apex, individual flowers ebracteolate; calyx with long setaceous teeth exceeding the tube, upper lobes joined higher or not; corolla scarcely exceeding the sharply subulate-tipped calyx-lobes, blue, violet or creamy-white; standard narrowly obovate with weakly developed auricles, flattish claw and no appendages; wings longer than keel, partially attached, sculptured; vexillarly filament attached for about half its length to the adaxially split sheath which is billowy and constricted at its base; anthers oblong, alternately long-basifixed and short-versatile; ovary substipitate, pubescent; style upcurved and thickened at the point of flexure; stigma somewhat flattened, penicillate; intrastaminal nectary present; fruit indehiscent, with a long sword shaped beak and furnished with glabrous spinulose or soft pubescent processes; pericarp adnate to seed or free; seed dark brown, oblong or obliquely reniform (Stirton 1981).

Season of growth

It is able to grow all-year-round if not limited due to extreme drought during summer or very low temperatures during winter.

Frost tolerance and regrowth

The different botanical varieties of Bituminaria bituminosa have different frost tolerance. The least tolerant is var. albomarginata that is burnt by mild frost of short duration; however the plant is often able to recover. The var. crassiuscula is present at the top of the Cañadas area growing at altitudes over 2000 m above sea level close to Teide Mountain in Tenerife and some populations are under snow for 3 or 4 months. The var. bituminosa from high altitude sites from the Mediterranean basin is the most frost tolerant of all, being able to survive through severe winters with minimum temperatures lower than -10^oC.

Response to photoperiod and light

Bituminaria bituminosa is a long-day plant which flowers and set seeds mainly in the spring. However, low number of flowers can be found all year round.

Drought tolerance

The botanical varieties of Bituminaria bituminosa have different drought tolerance and associated mechanisms to tolerate/avoid it. Var. albomarginata is the most drought tolerant of all. It originates from Lanzarote Island (Canary Islands, Spain) which has 150 mm to 300 mm of annual rainfall with rainfall only during the winter months. However, due to its proximity to the ocean, the relative humidity is high. It is able to remain green during summer with minimal leaf drop. The other botanical varieties are also very drought tolerant but they tend to drop more leaves to reduce evapotranspiration under severe drought conditions (Correal et al. 2003).

Tolerance of flooding

Bituminaria bituminosa is a drought tolerant plant with poor tolerance to water-logging, except for var. hulensis that grows alongside water courses.

Rainfall requirements

The botanical varieties are adapted to different rainfall regimes. The var. albomarginata is adapted to low rainfall (<300 mm); the var. crassiuscula is adapted to 500 mm of annual rainfall and the var. bituminosa is the most broadly distributed in the Mediterranean basin and Macaronesia from low annual rainfall (<200 mm) at low altitude to high annual (>1000 mm) rainfall and high altitude.

Soil requirements

It has a broad soil adaptation from deep sandy soils to stony shallow soils; however, in the Mediterranean basin, it is mostly found on alkaline soils. In the Canary Islands, Tederas can be found on soils with pH from 4.7 to 8.5.

Rhizobium relationships

Bituminaria bituminosa nodulates readily in native environments and the root-nodule bacteria species is a meso-rhizobium (Yates et al. 2009).

Ability to spread naturally

This species is not a strong colonizer. However, some recruitment is found near the mother plants enhancing long-term persistence.

Number of seeds per kg.

Thousand seed weight (TSW) of viable seed can vary from 20g (50,000 seeds/kg) to 30g (33,000 seeds/kg) (Correal et al. 2008), however, there is large variability for this character (Dini - Papanastasi et al. 2006).

Seed treatment before sowing

The seed is covered by the fruit and can not be separated for sowing. Scarification of the fruit enables water to penetrate the fruit easily and imbibe the seeds. Approximately 70% of seeds are hard and do not imbibe. For experimental purposes a small scalpel cut that can reach the seed coat will improve imbibition and germination.

Sowing depth and cover

Sowing depths of 3cm have provided a good establishment across several soil types from sand to loam soils in Western Australia.

Sowing time and rate

In Mediterranean environments with mild winters, sowing as early as possible after the first rains is recommended to allow plants to reach their first summer with a deep root system. In regions with cold winters, early spring planting should be appropriate.

Ability to compete with weeds

Once established, the leafy and compact morphological types (mainly of var. albomarginata) are competitive with weeds by shading the area that they occupy. At the seedling stage, some of the var. bituminosa forms that have strong early vigour can be more competitive.

Response to defoliation / grazing

Plants are able to tolerate heavy sheep grazing 3 or 4 times per year depending on growing conditions (Real D., unpublished). There is no experience with continuous grazing, but rotational grazing with cattle seemed to be appropriate for the species (Sternberg et al. 2006). Goat grazing trials are being conducted during 2009 and 2010 at the ICIA, Tenerife, Canary Islands.

Breeding system

Bituminaria bituminosa is a self-pollinated (Juan et al. 2004) diploid species - 2n=20 (Stirton 1981).

Dry matter yields

In Western Australia, in a region with 350 mm of annual rainfall, the dry matter production in experimental stands over 12 months was of 5 t/ha, with half of this production occurring during the summer/autumn dry period (December to April). Under irrigation, 10 t/ha of dry matter has been produced per year. In the ICIA, Tenerife, Canary Islands, var. bituminosa had a production of 7 t DM / ha year and 14 t DM / ha year for first and second year stands respectively, while var. albomarginata had a yearly DM production of 2 and 7 t/ha for first and second year respectively (Méndez and Fernández 1990).

Suitability for hay and silage

The traditional use of the Canary Islands is either direct grazing or as hay for milking goats (Méndez 2000).

Value as a stand-over or deferred feed

This species is able to remain green during long-dry summers in Western Australia without dropping its leaves. The capacity to defer plant production from one season to another (especially spring to summer) is one of the most valuable characteristic of this species.

Feeding value

Chemical analysis: The table below summarises the chemical analyses reported by Pecetti et al. (2007), Real et al. (unpublished) Sternberg et al. (2006), Ventura et al. (1999; 2000) and Álvarez et al. (2004) from studies conducted in Italy, Western Australia, Israel and Spain.

¹ Real et al. (unpublished) from studies in Western Australia
² Pecetti et al. (2007) from studies in Italy
³ Sternberg et al. (2006), from studies in Israel
⁴ Ventura et al. (1999; 2000) and Álvarez et al. (2004) from studies in the Canary Islands, Spain.
NDF, Neutral detergent fiber; ADF, acid detergent fiber; ADL, acid detergent lignin; CP, crude protein; WSC, water-soluble carbohydrates, Digest, digestibility in vitro; ME, metabolizable energy.
In a 24-day study with goats, the in vivo dry matter digestibility of Tedera hay (var. bituminosa from Canary Islands) was reported to be 60% with a metabolizable energy of 8.9 MJ/kg DM (Álvarez et al. 2004).

Acceptability/Palatability

Green feed
Cattle, sheep and goats (after a short period of getting familiar with the new fodder) eagerly graze var. albomarginata, var. crassiuscula and var. bituminosa from Canary Islands (Real, D. data not published 2008) and var. bituminosa from the Mediterranean basin during late spring, summer and autumn in Mediterranean environments (Gutman et al. 2000; Sternberg et al. 2006). During winter while there are many other very palatable options, Bituminaria is not preferentially grazed (Gutman et al. 2000). However, there is variablity within the species for winter palatability.

Dry feed
The consumption of hay from var. bituminosa from the Canary Islands was compared to Lucerne hay and the former was preferred (Méndez 2000). The common name “tedera” in the Canary Islands refers to the tea-like smell of the plants and hay (P. Mendez pers. comm.). The common name “Engraisse mouton” used in some parts of France indicates the high feeding value of the species (G. Gintzburger pers. comm.). However, some accessions of var. bituminosa from the Mediterranean basin are considered unpalatable due to a strong tar-like smell. This characteristic aroma appears to be the result of a combination of several substances such as phenolics, sulphurated compounds, sesquiterpenes and probably short-chain hydrocarbons (Tava et al. 2007).

Anti-quality factors

There are four furanocoumarins (psoralen, angelicin, xanthotoxin and bergapten) present in leaves, stems and/or fruits of this species that vary in proportion with total concentration from 100 ppm to 8000 ppm (Innocenti et al. 1997; Martínez et al. 2009; Méndez et al. 2001; Tava et al. 2007; Zobel et al. 1991) Pterocarpan and chromene derivatives were also found (Pistelli et al. 2003). Furanocoumarins are correlated to photosensitisation in grazing animals (Oertli et al. 1984; Oertli et al. 1983). However, there are no reports in the literature or by farmers that Bituminaria bituminosa has caused photosensitization or any other health problem in grazing animals. Regarding other secondary compounds, a number of accessions were analyzed in the Chemistry Centre of Western Australia and the content of total polyphenols was < 2% and the condensed tannins was <0.8% in a dry weight basis. Similar results were found by Pecetti et al. (2007) where total polyphenols were less than 1.4% in a dry weight basis.

Toxicity

No toxicity has been reported for Bituminaria bituminosa. There are only reports for some accessions from the Mediterranean basin of being unpalatable due to its smell.

Seed yield

Seed production research conducted up to 2009 has mainly involved characterization of the variability in seed production by hand harvesting individual plants. Terenti (2008) reported seed yields of up to 417 kg/ha. However these yields were obtained over a 12-day hand-harvest period. In Spain, Correal et al. (2008) reported hand-harvested mean seed yields of 50g/plant for var. albomarginata, 38 g/plant for var crassiuscula and 43 g/plant for var. bituminosa.

Cultivars

No cultivars are commercially available as at 2009.

Diseases and pests

There are some reports of Rhizoctonia can affected root development in sandy soils in Western Australia (M. Gerding, 2008 pers. comm.). Some plants within the species are susceptible to blue-green aphid (Acyrthosiphon kondoi) but they appear to be resistant to spotted alfalfa aphids (Therioaphis trifolii) (R. Nair 2008 pers. comm.) and cowpea aphid (Aphis craccivora). Some plants have been infected by AMV (Alfalfa Mosaic Virus) causing a yellowing of leaves. At the ICIA, Tenerife, Canary Islands, severe infestations have occurred with Icerya purchasi (Homoptera: common name cottony-cushion scale ) pers. comm. P. Méndez.

Main references

Álvarez S, Méndez P, Díaz C, Fresno M (2004) Ingestión, composición química y digestibilidad in vivo de tedera (Bituminaria bituminosa (L.) Stirton). In 'XLIV reunión científica de la S.E.E.P. pastos y ganadería extensiva'. Salamanca pp. 337-340.

Correal E, Hoyos A, Ríos S, Méndez P, Real D, Snowball R, Costa J (2008) Seed production of Bituminaria bituminosa: size, production, retention and germination capacity of the legumes. In 'Options Méditerranéennes'. Elvas, Portugal.

Correal E, Monino I, Méndez P, Ríos S (2003) Valoración agronómica de siete poblaciones de Bituminaria bituminosa: efecto de la sequía estival y siega sobre su persistencia y producción de hoja. In 'Pastos, desarrollo y conservación' pp. 34-40.

Dini - Papanastasi O, Lazaridou MG, Papanastasis VP (2006) Collection and evaluation of genetic material of Bituminaria bituminosa (L.) Stirton from various regions of Greece - Preliminary results. In 'Rangelands of lowlands and semi-mountainous areas: means of rural development. Proceedings of the 4th Panhellenic Rangeland Congress
'. Volos, Greece. (Ed. P.D.Platis) pp. 273-279.

Gutman M, Perevolotsky A, Sternberg M (2000) Grazing effects on a perennial legume, Bituminaria bituminosa (L.) Stirton, in a Mediterranean rangeland. In 'Cahiers Options Mediterraneennes. 2000. 45: 299-303. 3 ref.'. (Ed. L Sulas).

Innocenti G, Piovan A, Filippini R, Caniato R, Cappelletti EM (1997) Quantitative recovery of furanocoumarins from Psoralea bituminosa. Phytochemical Analysis 8, 84-86.

Juan A, Monino I, Correal E, Méndez P, Crespo MB (2004) Comparación de las tasas de fructificación de Bituminaria bituminosa (Leguminosae) bajo condiciones de cultivo en canarias y la península Ibérica. In 'Pastos y ganadería extensiva'. (Eds BG Criado, AG Cuidad, BRVd Aldana, I Zabalgogeazcoa) pp. 111-115.

Martínez S, Correal E, Real D, Ortuño A, Del Río JA (2009) Bituminaria bituminosa: a source of furanocoumarins of pharmaceutical interest. In 'Encyclopedia of Medicinal Plants' pp. 1-29.

Méndez P (2000) El heno de tedera (Bituminaria bituminosa): un forraje apetecible para el caprino. In '3 Reunión Ibérica de Pastos y Forraxes'. Galicia, Spain pp. 412-414.

Méndez P, Díaz E, Rivero R (2001) Contenido en cumarinas del forraje verde de tedera (Bituminaria bituminosa). In 'XLI Reunión científica de la S.E.E.P.' pp. 335-339.

Méndez P, Fernández M (1990) Interés forrajero de las variedades de Bituminaria bituminosa (L.) Stirton ("tedera") de Canarias. In 'XXX Reunión científica de la sociedad Española para el estudio de los pastos'. Donostia-San Sabastian pp. 264-272.

Méndez P, Santos A, Correal E, Ríos S (2006) Agronomic traits as forage crops of nineteen populations of Bituminaria bituminosa. Grassland Science in Europe 11, 300-302.

Oertli EH, Beier RC, Ivie GW, Rowe LD (1984) Linear furocoumarins and other constituents from Thamnosma texana. Phytochemistry 23, 439-441.

Oertli EH, Rowe LD, Lovering SL, Ivie GW, Bailey EM (1983) Phototoxic effect of Thamnosma texana (Dutchman's breeches) in sheep. American Journal of Veterinary Research 44, 1126-1129.

Pecetti L, Tava A, Pagnotta MA, Russi L (2007) Variation in forage quality and chemical composition among Italian accessions of Bituminaria bituminosa (L.) Stirt. Journal of the Science of Food and Agriculture 87, 985-991.

Pistelli L, Noccioli C, Appendino G, Bianchi F, Sterner O, Ballero. M (2003) Pterocarpans from Bituminaria morisiana and Bituminaria bituminosa. Phytochemistry 64, 595-598.

Sternberg M, Gishri N, Mabjeesh SJ (2006) Effects of grazing on Bituminaria bituminosa (L.) Stirton: a potential forage crop in Mediterranean grasslands. Journal of Agronomy and Crop Science 192, 399-407.

Stirton CH (1981) Tribe 11. Psoraleeae (Benth.) Rydb. (1919). In 'Advances in legume systematics. Part 1.'. (Ed. RMPPH Raven) pp. 337-343.

Tava A, Pecetti L, Ricci M, Pagnotta MA, Russi L (2007) Volatile compounds from leaves and flowers of Bituminaria bituminosa (L.) Stirt. (Fabaceae) from Italy. Flavour and Fragrance Journal 22, 363-370.

Terenti OA (2008) Producción y calidad de semilla según edad cronológica de Bituminaria bituminosa en San Luis. Revista Argentina de Produccion Animal 28, 489-490.

Ventura MR, Flores MP, Castanon JIR (1999) Nutritive value of forage shrubs: Bituminaria bituminosa, Acacia salicina and Medicago arborea. In 'Cahiers Options Mediterraneennes. 1999. 39: 171-173. 6 ref.'. (Ed. M Etienne).

Ventura MR, Méndez P, Flores MP, Rodríguez R, Castanon JIR (2000) Energy and protein content of tedera (Bituminaria bituminosa). In 'Cahiers Options Mediterraneennes. 2000. 45: 219-221. 11 ref.'. (Ed. L Sulas).

Yates RJ, Real D, Revell C, Howieson JG (2009) Developing inoculant quality root-nodule bacteria for Bituminaria bituminosa: a perennial pasture legume with potential for dryland agriculture. In 'THe 16th International Congress on nitrogen fixation'. Montana, USA.

Zobel AM, Brown SA, March RE (1991) Histological localization of psoralens in fruits of Psoralea bituminosa. Canadian Journal of Botany 69, 1673-1678.

Zohary M (1972) 'Flora Palestina. Part 2.' (Israel Academy of Sciences and Humanities: Jerusalem).

[Prepared and edited in March 2009]

1 Department of Agriculture and Food, Western Australia (DAFWA), South Perth, WA 6151, Australia
2 Future Farm Industries Cooperative Research Centre, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
3 School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
4 IMIDA-Murcia, Dep. Recursos Naturales, Estación Sericícola, calle Mayor s/n, 30150 La Alberca (Murcia), Spain
5 Unidad de Producción Animal, Pastos y Forrajes Instituto Canario de Investigaciones Agrarias, Apartado 60, 38200 La Laguna, Tenerife I. Canarias, Spain
6 CIBIO, University of Alicante, Apartado 99, 03080 Alicante, Spain
7 Department of Plant Sciences, Tel Aviv University, Tel Aviv 69978, Israel
8 N.AG.RE.F. - Forest Research Institute, GR - 570 06 Vassilika, Thessaloniki - Greece
9 CRA-FLC Centro di ricerca per le Produzioni Foraggere e Lattiero Casearie viale Piacenza 29, 26900 Lodi, Italy