T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Orobanche minor (Broomrape)

Kingdom: Plantae
(Unranked): Angiosperms
(Unranked): Eudicots
(Unranked): Asterids
Order: Lamiales
Family: Orobanchaceae
Genus: Orobanche
Species: O. minor
Binomial name: Orobanche minor
Common names: Broomrape, Hellroot, Common broomrape, Lesser broomrape,small broomrape,clover broomrape.

Orobanche minoris a holoparasitic angiosperm belonging to the genus Orobanche; a genus of about 150 non-photosynthetic plants that parasitise other autotrophic (self feeding) plants by attaching to their roots. It is native to the Middle East and was probably introduced into New Zealand with contaminated seed. 
It is a variable species that occurs on numerous hosts of many different plant families. Some of the common hosts are in the families of Asteraceae, Fabaceae and Amaryllidaceae.

Orobanche minoris is a fleshy, herbaceous, annual, plant that grows up to 50 cm tall. It parasitise plants by feeding on their roots through an appendages called a haustoria. The haustorium penetrates the host plant's cell wall and siphon nutrients from the space between the cell wall and plasma membrane but does not penetrate the plant's cell membrane itself.
Orobanche minoris lacks chlorophyll and hence has no green colouration. The stems that are produced above ground are solely for the purpose of setting seed. The small leaves are alternate, triangular shaped and are vestigial (functionless). Flowers are borne on terminal clusters and are snapdragon-like, 1.3 cm long with purple-tinged petals.
A single plant is capable of producing hundreds of thousands of small dust like seeds. The seeds remain viable for 10 or more years. It is a noxious weed and it may infest crops. Heavy infestations can cause crop failure. Their underground existence and intimate attachment to their hosts makes their control extremely difficult.

The photo below shows the bulb like haustorium of Orobanche minoris attached to the host plant's root. The mass of roots are succulent adventitious roots of the parasite. These roots will attach to other roots of the host forming a secondary haustorium.



Broomrape flowers

The hairy stem.og Orobanche minor