Seed Structure Characteristics of Orobanche cumana Populations

Abstract

Sunflower broomrape Orobanche cumana WALLR. is a rapidly growing threat to the oil crop production in many countries. Fast adaptation to new environments and increasing host resistance suggests that phenotypically distinctive populations of the weed may have evolved. The classification of the species and the differentiation of such populations on the base of seed micromorphological characters were attempted. Morphometric measurements allowed the distinction of O. cumana from several other Orobanche and Phelipanche species. An irregularly thickened cell wall of the anticlinal testa cells differentiated O. cumana and O. cernua from O. caryophyllacea, O. crenata, O. minor, P. aegyptiaca, P. arenaria and P. ramosa. However, populations of sunflower broomrape from five European countries and China could not be separated from each other on the base of micromorphological seed characters. In contrast, length to width measurements indicated that the Asian samples had a slightly different seed shape which was less elongated than the European samples. However, this seemingly geographic effect may as well be a consequence of sampling which comprised a higher rate of the so-called modern races E-H in the European samples.

Fruit and seed morphology of the tribe Orobancheae (Orobanchaceae) genera in Turkey and its taxonomic significance

“…SEM results indicated the presence of polygonal cells on the seed surface, which gave a reticulate appearance to the seed. This pattern show constancy among the majority of the genera Orobanchaceae, as previously pointed out by Boeshore (), Musselman and Mann (), Teryokhin et al (), Abu Sbaih and Jury (), Plaza et al (), Shavvon and Mehrvarz () and Krupp et al (). This reticulated membranous testa increases the contact surface of the seed, and subsequently increases water absorption, thus enhancing the adherence and germination capacity of seeds (Ryding , Joel et al ).…”

Main drivers of broomrape regulation. A review

“…Seed shape, size, and testa micromorphology are potential traits that can be used to discriminate different species, countries, or populations. However, geographic origin and race have no significant effect on seed phenotypic traits (Krupp et al 2015). After a conditioning period, seeds nearby roots are ready to germinate in response to specific signal molecules released by the host plant in its rhizosphere (Stewart and Press 1990;Penuelas and Llusia 2004).…”