Apium prostratum

Abstract: European representatives of Apium sensu lato (Apiaceae), and Apium prostratum and Naufraga baleari ca., were studied with morphological, fruit anatomical, and palynological methods. Morphometric data were compared with phylogenetic results from previous molecular studies. This confirms that most of the European Apium species belong to a separate group corresponding to the previously named genus Helosciadium. All these species had previ ously been formally named as Helosciadium species, except for the new combination Helosciadium bermejoi, which is formally described here. Molecular studies place Apium prostratum and Naufraga balearica close to Apium graveolens, the type species of Apium. Our morphometric results show similarities of Naufraga with H. bermejoi, but fruit anatomy distinguishes it both from Helosciadium and from A. graveolenslprostratum. The placement of Cyclo spermum leptophyllum in a separate genus is confirmed. Diagnostic keys to the genera and Helosciadium species, and an annotated checklist are given.

Abstract: Two Apium accessions were compared with the commercial cultivar ‘Tall Utah’ 52–70R (A. graveolens [L.]) for resistance to Spodoptera exigua (Hubner)(Lepidoptera: Noctuidae). Oviposition rate was not significantly different between the three genotypes. In all accessions, eggs were usually placed on the upper half of the plants. Implications of this oviposition pattern on S. exigua management in celery are discussed. The wild species A. prostratum ssp prostratum var filiform (A230) showed a significantly higher resistance to S. exigua than 52–70R. The levels of carcinogenic and mutagenic linear furanocoumarins in the commercial cultivar 52–70R (1.41 μg/g in the petioles; 5.85 μg/g in the leaves) and in the plant accession A. nodiflorum (5.40 μg/g in the petioles; 2.99 μg/g in the leaves) were far below the concentration reported to produce acute contact dermatitis (18.0 μg/g). The levels of furanocoumarins in A. prostratum petioles (186.14 μg/g) and leaves (326.45 μg/g) were 10 and 18 times higher, respectively, than the concentration known to cause contact dermatitis. However, resistance in A. prostratum was primarily due to non-preference and the linear furanocoumarins did not induce non-preference. Therefore, the resistance shown by this plant accession does not appear to be furanocoumarin-based and may be suitable for transfer to commercial celery for use in S. exigua management.

Abstract: This paper describes the effects of temperature and simple or multiple dormancy-breaking treatments (potassium nitrate, surgical treatment, gibberellic acid (GA3), after-ripening at 45°C and nitrogen dioxide gas) on germination of five endemic and geographically restricted herbaceous perennials (Apium prostratum Vent. subsp. phillipii Keighery ms, Goodenia stenophylla F.Muell., Marianthus granulatus (Turcz.) Benth, Myriocephalus suffruticosus Benth. and Velleia foliosa (Benth.) K.Krause) from the species-rich south-west of Western Australia. Except for seeds of A. prostratum that were non-dormant, seeds were partially dormant or fully dormant when incubated without pre-treatment at three temperatures (15, 20 and 25/10°C). Low germination (≤52%) was detected in M. granulatus under the best identified conditions, and seeds of G. stenophylla showed little to no response to any germination cue. In M. granulatus, M. suffruticosus and V. foliosa combinations of treatments were found that led to enhanced germination and in the case of V. foliosa, germination was not significantly different from a tetrazolium test of viability when seeds were surgically treated and then incubated with KNO3. Although none of the species studied exhibited physical dormancy, surgical excision of the seed coat in the vicinity of the embryo featured in the most successful combination of treatments in every case. Whilst seeds of M. granulatus responded positively to surgical treatment, after-ripening of seeds at 45°C for 2, 4 or 6 weeks did not increase either speed or final germination compared with other treatments. The mean time to germinate (MTG) ranged from 12.6 days (A. prostratum ssp. phillipii) to 46.5 days (G. stenophylla) under the best treatment conditions for each species.