Germination ecology, emergence and host detection in Cuscuta campestris

• Published in: Weed research Vol. 45; no. 4; pp. 270 - 278
• Main Authors: Benvenuti, S, Dinelli, G, Bonetti, A, Catizone, P
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.08.2005; Blackwell Science
• Subjects: Beta vulgaris subsp. vulgaris; Biological and medical sciences; chlorophyll; Cuscuta campestris; developmental stages; dormancy breaking; fallow; Fundamental and applied biological sciences. Psychology; fungal spores; host-parasite relationships; parasitic plants; Parasitic plants. Weeds; parasitic weed; phenology; phototropism; Phytopathology. Animal pests. Plant and forest protection; seed dormancy; seed germination; seed scarification; seedling emergence; sugar beet; sugar crops; temperature; Weeds; Germany; Weed; Germination; Ecology; seed germination; Convolvulaceae; Dormancy; Cuscuta campestris; seed dormancy; parasitic weed; Dicotyledones; Weed science; Seed; Angiospermae; Spermatophyta; phototropism; Detection; Parasitic plant
• ISSN: 0043-1737; 1365-3180
• DOI: 10.1111/j.1365-3180.2005.00460.x

Summary Trials were carried out to study the germination and dormancy of Cuscuta campestris Y. (dodder) seeds and factors influencing the success of early parasitisation of sugarbeet. Primary dormancy can be removed by seed scarification. Germination was negligible at 10°C and optimal at 30°C, while it was not influenced by light. Seed burial induced a cycle of induction and breaking of secondary dormancy. Seedling emergence was inversely proportional to the depth of seed burial and only seed buried within 5 cm of the soil surface emerged. Storage of C. campestris seeds in a laboratory for 12 years resulted in the loss of primary dormancy, enabling the germination of all viable seeds. Host infection (i.e. protrusion of parasite haustoria from host tissue) was heavily influenced by host growth stage. Tropism towards a host was due to the perception of light transmitted by green parts of sugarbeet plants. Insertion of a transparent glass sheet between host leaves and parasite seedlings did not modify this response. This phototropism permitted Cuscuta to identify host plants with high chlorophyll content as a function of the lower red/far red ratio of transmitted light.