Orobanchaceae

OrobancheMinorIreland (2)

Striga bilabiata MS4167

Broomrape (Cistanche tubulosa) Negev

Castilleja purpurea

Pedicularis zeylanica-Silent Valley-2016-08-13-001

Orobanchaceae, commonly known as the broomrape family, is a family of flowering plants that are primarily known for their parasitic lifestyle. The family is large and diverse, encompassing around 90 genera and over 2000 species. Members of this family are found in a variety of habitats across the world, from temperate to tropical regions. The Orobanchaceae family is significant both ecologically and economically, with some species being studied for their unique parasitic mechanisms, while others are considered pests in agriculture.

Characteristics

Plants in the Orobanchaceae family are characterized by their lack of chlorophyll, which is unusual among flowering plants. This lack of chlorophyll means that they are unable to perform photosynthesis, the process by which most plants produce their own food. Instead, Orobanchaceae species are holoparasitic or hemiparasitic, obtaining nutrients and water from the roots of host plants. Holoparasites, such as the genus Orobanche, are completely dependent on their host for all nutrients, while hemiparasites, like those in the genus Striga, can perform some photosynthesis but still rely significantly on their host for survival.

Distribution and Habitat

Orobanchaceae species are distributed globally, from the arctic tundra to tropical forests. They are most commonly found in temperate regions and are especially diverse in the Mediterranean area. These plants typically inhabit areas where their host plants are abundant, which can vary widely from grasslands to forests, depending on the species.

Economic Impact

Several species within the Orobanchaceae family, particularly those in the genera Orobanche and Striga, are known to be significant agricultural pests. Striga, also known as witchweed, affects cereal crops in Africa, Asia, and Australia, causing substantial yield losses each year. Orobanche species target a wide range of legumes and other crops, leading to economic losses in affected regions. Management of these parasitic plants is challenging due to their complex life cycle and close relationship with host plants.

Ecological Role

Despite their reputation as pests, Orobanchaceae species play important roles in their ecosystems. As parasites, they can influence the composition and structure of plant communities by targeting dominant plant species, potentially increasing biodiversity. Some species are also important for pollinators, offering nectar and pollen to a variety of insects.

Taxonomy

The taxonomy of Orobanchaceae has undergone significant changes with the advent of molecular phylogenetics. It was previously classified under the family Scrophulariaceae, but genetic studies have led to its recognition as a distinct family. The family is now divided into several tribes, with Orobancheae and Rhinantheae being among the most well-known.

Conservation

Conservation of Orobanchaceae species is complex due to their parasitic nature and the negative impact some species have on agriculture. However, some species are rare and face threats from habitat loss and climate change. Conservation efforts for these species require a nuanced approach that considers both the ecological importance of parasitic plants and their impact on human activities.